2005-04-17 02:20:36 +04:00
/*
* linux / kernel / compat . c
*
* Kernel compatibililty routines for e . g . 32 bit syscall support
* on 64 bit kernels .
*
* Copyright ( C ) 2002 - 2003 Stephen Rothwell , IBM Corporation
*
* This program is free software ; you can redistribute it and / or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation .
*/
# include <linux/linkage.h>
# include <linux/compat.h>
# include <linux/errno.h>
# include <linux/time.h>
# include <linux/signal.h>
# include <linux/sched.h> /* for MAX_SCHEDULE_TIMEOUT */
# include <linux/syscalls.h>
# include <linux/unistd.h>
# include <linux/security.h>
2006-03-26 13:37:29 +04:00
# include <linux/timex.h>
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# include <linux/export.h>
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# include <linux/migrate.h>
2006-09-29 13:00:28 +04:00
# include <linux/posix-timers.h>
timers: fix itimer/many thread hang
Overview
This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together
with the help of Roland McGrath, the owner and original writer of this code.
The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads. It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.
This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."
Code Changes
This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine. (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.) To do this, at each tick we now update fields in
signal_struct as well as task_struct. The run_posix_cpu_timers() function
uses those fields to make its decisions.
We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:
struct thread_group_cputime {
struct task_cputime totals;
};
struct thread_group_cputime {
struct task_cputime *totals;
};
We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers). The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends. In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention). For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu(). The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().
We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel. The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields. The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures. The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated. The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU. Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.
Non-SMP operation is trivial and will not be mentioned further.
The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().
All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.
Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away. All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline. When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.
Performance
The fix appears not to add significant overhead to existing operations. It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below). Overall it's a wash except in those
two cases.
I've since done somewhat more involved testing on a dual-core Opteron system.
Case 1: With no itimer running, for a test with 100,000 threads, the fixed
kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
all of which was spent in the system. There were twice as many
voluntary context switches with the fix as without it.
Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
an unmodified kernel can handle), the fixed kernel ran the test in
eight percent of the time (5.8 seconds as opposed to 70 seconds) and
had better tick accuracy (.012 seconds per tick as opposed to .023
seconds per tick).
Case 3: A 4000-thread test with an initial timer tick of .01 second and an
interval of 10,000 seconds (i.e. a timer that ticks only once) had
very nearly the same performance in both cases: 6.3 seconds elapsed
for the fixed kernel versus 5.5 seconds for the unfixed kernel.
With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.
Since the fix affected the rlimit code, I also tested soft and hard CPU limits.
Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
running), the modified kernel was very slightly favored in that while
it killed the process in 19.997 seconds of CPU time (5.002 seconds of
wall time), only .003 seconds of that was system time, the rest was
user time. The unmodified kernel killed the process in 20.001 seconds
of CPU (5.014 seconds of wall time) of which .016 seconds was system
time. Really, though, the results were too close to call. The results
were essentially the same with no itimer running.
Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
(where the hard limit would never be reached) and an itimer running,
the modified kernel exhibited worse tick accuracy than the unmodified
kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise,
performance was almost indistinguishable. With no itimer running this
test exhibited virtually identical behavior and times in both cases.
In times past I did some limited performance testing. those results are below.
On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds. Performance with eight, four and one
thread were comparable. Interestingly, the timer ticks with the fix seemed
more accurate: The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick. Both cases were configured for an interval of
0.01 seconds. Again, the other tests were comparable. Each thread in this
test computed the primes up to 25,000,000.
I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix. In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable). System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite
accurate. There is obviously no comparable test without the fix.
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-12 20:54:39 +04:00
# include <linux/times.h>
2009-01-07 01:41:02 +03:00
# include <linux/ptrace.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 11:04:11 +03:00
# include <linux/gfp.h>
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# include <asm/uaccess.h>
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static int compat_get_timex ( struct timex * txc , struct compat_timex __user * utp )
{
memset ( txc , 0 , sizeof ( struct timex ) ) ;
if ( ! access_ok ( VERIFY_READ , utp , sizeof ( struct compat_timex ) ) | |
__get_user ( txc - > modes , & utp - > modes ) | |
__get_user ( txc - > offset , & utp - > offset ) | |
__get_user ( txc - > freq , & utp - > freq ) | |
__get_user ( txc - > maxerror , & utp - > maxerror ) | |
__get_user ( txc - > esterror , & utp - > esterror ) | |
__get_user ( txc - > status , & utp - > status ) | |
__get_user ( txc - > constant , & utp - > constant ) | |
__get_user ( txc - > precision , & utp - > precision ) | |
__get_user ( txc - > tolerance , & utp - > tolerance ) | |
__get_user ( txc - > time . tv_sec , & utp - > time . tv_sec ) | |
__get_user ( txc - > time . tv_usec , & utp - > time . tv_usec ) | |
__get_user ( txc - > tick , & utp - > tick ) | |
__get_user ( txc - > ppsfreq , & utp - > ppsfreq ) | |
__get_user ( txc - > jitter , & utp - > jitter ) | |
__get_user ( txc - > shift , & utp - > shift ) | |
__get_user ( txc - > stabil , & utp - > stabil ) | |
__get_user ( txc - > jitcnt , & utp - > jitcnt ) | |
__get_user ( txc - > calcnt , & utp - > calcnt ) | |
__get_user ( txc - > errcnt , & utp - > errcnt ) | |
__get_user ( txc - > stbcnt , & utp - > stbcnt ) )
return - EFAULT ;
return 0 ;
}
static int compat_put_timex ( struct compat_timex __user * utp , struct timex * txc )
{
if ( ! access_ok ( VERIFY_WRITE , utp , sizeof ( struct compat_timex ) ) | |
__put_user ( txc - > modes , & utp - > modes ) | |
__put_user ( txc - > offset , & utp - > offset ) | |
__put_user ( txc - > freq , & utp - > freq ) | |
__put_user ( txc - > maxerror , & utp - > maxerror ) | |
__put_user ( txc - > esterror , & utp - > esterror ) | |
__put_user ( txc - > status , & utp - > status ) | |
__put_user ( txc - > constant , & utp - > constant ) | |
__put_user ( txc - > precision , & utp - > precision ) | |
__put_user ( txc - > tolerance , & utp - > tolerance ) | |
__put_user ( txc - > time . tv_sec , & utp - > time . tv_sec ) | |
__put_user ( txc - > time . tv_usec , & utp - > time . tv_usec ) | |
__put_user ( txc - > tick , & utp - > tick ) | |
__put_user ( txc - > ppsfreq , & utp - > ppsfreq ) | |
__put_user ( txc - > jitter , & utp - > jitter ) | |
__put_user ( txc - > shift , & utp - > shift ) | |
__put_user ( txc - > stabil , & utp - > stabil ) | |
__put_user ( txc - > jitcnt , & utp - > jitcnt ) | |
__put_user ( txc - > calcnt , & utp - > calcnt ) | |
__put_user ( txc - > errcnt , & utp - > errcnt ) | |
__put_user ( txc - > stbcnt , & utp - > stbcnt ) | |
__put_user ( txc - > tai , & utp - > tai ) )
return - EFAULT ;
return 0 ;
}
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COMPAT_SYSCALL_DEFINE2 ( gettimeofday , struct compat_timeval __user * , tv ,
struct timezone __user * , tz )
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{
if ( tv ) {
struct timeval ktv ;
do_gettimeofday ( & ktv ) ;
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if ( compat_put_timeval ( & ktv , tv ) )
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return - EFAULT ;
}
if ( tz ) {
if ( copy_to_user ( tz , & sys_tz , sizeof ( sys_tz ) ) )
return - EFAULT ;
}
return 0 ;
}
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COMPAT_SYSCALL_DEFINE2 ( settimeofday , struct compat_timeval __user * , tv ,
struct timezone __user * , tz )
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{
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struct timeval user_tv ;
struct timespec new_ts ;
struct timezone new_tz ;
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if ( tv ) {
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if ( compat_get_timeval ( & user_tv , tv ) )
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return - EFAULT ;
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new_ts . tv_sec = user_tv . tv_sec ;
new_ts . tv_nsec = user_tv . tv_usec * NSEC_PER_USEC ;
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}
if ( tz ) {
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if ( copy_from_user ( & new_tz , tz , sizeof ( * tz ) ) )
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return - EFAULT ;
}
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return do_sys_settimeofday ( tv ? & new_ts : NULL , tz ? & new_tz : NULL ) ;
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}
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static int __compat_get_timeval ( struct timeval * tv , const struct compat_timeval __user * ctv )
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{
return ( ! access_ok ( VERIFY_READ , ctv , sizeof ( * ctv ) ) | |
__get_user ( tv - > tv_sec , & ctv - > tv_sec ) | |
__get_user ( tv - > tv_usec , & ctv - > tv_usec ) ) ? - EFAULT : 0 ;
}
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static int __compat_put_timeval ( const struct timeval * tv , struct compat_timeval __user * ctv )
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{
return ( ! access_ok ( VERIFY_WRITE , ctv , sizeof ( * ctv ) ) | |
__put_user ( tv - > tv_sec , & ctv - > tv_sec ) | |
__put_user ( tv - > tv_usec , & ctv - > tv_usec ) ) ? - EFAULT : 0 ;
}
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static int __compat_get_timespec ( struct timespec * ts , const struct compat_timespec __user * cts )
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{
return ( ! access_ok ( VERIFY_READ , cts , sizeof ( * cts ) ) | |
__get_user ( ts - > tv_sec , & cts - > tv_sec ) | |
__get_user ( ts - > tv_nsec , & cts - > tv_nsec ) ) ? - EFAULT : 0 ;
}
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static int __compat_put_timespec ( const struct timespec * ts , struct compat_timespec __user * cts )
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{
return ( ! access_ok ( VERIFY_WRITE , cts , sizeof ( * cts ) ) | |
__put_user ( ts - > tv_sec , & cts - > tv_sec ) | |
__put_user ( ts - > tv_nsec , & cts - > tv_nsec ) ) ? - EFAULT : 0 ;
}
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int compat_get_timeval ( struct timeval * tv , const void __user * utv )
{
if ( COMPAT_USE_64BIT_TIME )
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return copy_from_user ( tv , utv , sizeof ( * tv ) ) ? - EFAULT : 0 ;
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else
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return __compat_get_timeval ( tv , utv ) ;
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}
EXPORT_SYMBOL_GPL ( compat_get_timeval ) ;
int compat_put_timeval ( const struct timeval * tv , void __user * utv )
{
if ( COMPAT_USE_64BIT_TIME )
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return copy_to_user ( utv , tv , sizeof ( * tv ) ) ? - EFAULT : 0 ;
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else
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return __compat_put_timeval ( tv , utv ) ;
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}
EXPORT_SYMBOL_GPL ( compat_put_timeval ) ;
int compat_get_timespec ( struct timespec * ts , const void __user * uts )
{
if ( COMPAT_USE_64BIT_TIME )
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return copy_from_user ( ts , uts , sizeof ( * ts ) ) ? - EFAULT : 0 ;
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else
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return __compat_get_timespec ( ts , uts ) ;
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}
EXPORT_SYMBOL_GPL ( compat_get_timespec ) ;
int compat_put_timespec ( const struct timespec * ts , void __user * uts )
{
if ( COMPAT_USE_64BIT_TIME )
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return copy_to_user ( uts , ts , sizeof ( * ts ) ) ? - EFAULT : 0 ;
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else
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return __compat_put_timespec ( ts , uts ) ;
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}
EXPORT_SYMBOL_GPL ( compat_put_timespec ) ;
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int compat_convert_timespec ( struct timespec __user * * kts ,
const void __user * cts )
{
struct timespec ts ;
struct timespec __user * uts ;
if ( ! cts | | COMPAT_USE_64BIT_TIME ) {
* kts = ( struct timespec __user * ) cts ;
return 0 ;
}
uts = compat_alloc_user_space ( sizeof ( ts ) ) ;
if ( ! uts )
return - EFAULT ;
if ( compat_get_timespec ( & ts , cts ) )
return - EFAULT ;
if ( copy_to_user ( uts , & ts , sizeof ( ts ) ) )
return - EFAULT ;
* kts = uts ;
return 0 ;
}
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static long compat_nanosleep_restart ( struct restart_block * restart )
{
struct compat_timespec __user * rmtp ;
struct timespec rmt ;
mm_segment_t oldfs ;
long ret ;
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restart - > nanosleep . rmtp = ( struct timespec __user * ) & rmt ;
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oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
ret = hrtimer_nanosleep_restart ( restart ) ;
set_fs ( oldfs ) ;
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if ( ret = = - ERESTART_RESTARTBLOCK ) {
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rmtp = restart - > nanosleep . compat_rmtp ;
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if ( rmtp & & compat_put_timespec ( & rmt , rmtp ) )
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return - EFAULT ;
}
return ret ;
}
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COMPAT_SYSCALL_DEFINE2 ( nanosleep , struct compat_timespec __user * , rqtp ,
struct compat_timespec __user * , rmtp )
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{
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struct timespec tu , rmt ;
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mm_segment_t oldfs ;
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long ret ;
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if ( compat_get_timespec ( & tu , rqtp ) )
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return - EFAULT ;
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if ( ! timespec_valid ( & tu ) )
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return - EINVAL ;
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oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
ret = hrtimer_nanosleep ( & tu ,
rmtp ? ( struct timespec __user * ) & rmt : NULL ,
HRTIMER_MODE_REL , CLOCK_MONOTONIC ) ;
set_fs ( oldfs ) ;
2014-09-06 14:18:07 +04:00
/*
* hrtimer_nanosleep ( ) can only return 0 or
* - ERESTART_RESTARTBLOCK here because :
*
* - we call it with HRTIMER_MODE_REL and therefor exclude the
* - ERESTARTNOHAND return path .
*
* - we supply the rmtp argument from the task stack ( due to
* the necessary compat conversion . So the update cannot
* fail , which excludes the - EFAULT return path as well . If
* it fails nevertheless we have a bigger problem and wont
* reach this place anymore .
*
* - if the return value is 0 , we do not have to update rmtp
* because there is no remaining time .
*
* We check for - ERESTART_RESTARTBLOCK nevertheless if the
* core implementation decides to return random nonsense .
*/
if ( ret = = - ERESTART_RESTARTBLOCK ) {
2008-02-01 20:35:31 +03:00
struct restart_block * restart
= & current_thread_info ( ) - > restart_block ;
restart - > fn = compat_nanosleep_restart ;
2008-02-10 11:17:43 +03:00
restart - > nanosleep . compat_rmtp = rmtp ;
2005-04-17 02:20:36 +04:00
2014-02-02 06:54:11 +04:00
if ( rmtp & & compat_put_timespec ( & rmt , rmtp ) )
2005-04-17 02:20:36 +04:00
return - EFAULT ;
}
2007-10-16 01:13:56 +04:00
return ret ;
2005-04-17 02:20:36 +04:00
}
static inline long get_compat_itimerval ( struct itimerval * o ,
struct compat_itimerval __user * i )
{
return ( ! access_ok ( VERIFY_READ , i , sizeof ( * i ) ) | |
( __get_user ( o - > it_interval . tv_sec , & i - > it_interval . tv_sec ) |
__get_user ( o - > it_interval . tv_usec , & i - > it_interval . tv_usec ) |
__get_user ( o - > it_value . tv_sec , & i - > it_value . tv_sec ) |
__get_user ( o - > it_value . tv_usec , & i - > it_value . tv_usec ) ) ) ;
}
static inline long put_compat_itimerval ( struct compat_itimerval __user * o ,
struct itimerval * i )
{
return ( ! access_ok ( VERIFY_WRITE , o , sizeof ( * o ) ) | |
( __put_user ( i - > it_interval . tv_sec , & o - > it_interval . tv_sec ) |
__put_user ( i - > it_interval . tv_usec , & o - > it_interval . tv_usec ) |
__put_user ( i - > it_value . tv_sec , & o - > it_value . tv_sec ) |
__put_user ( i - > it_value . tv_usec , & o - > it_value . tv_usec ) ) ) ;
}
2012-12-25 02:28:40 +04:00
COMPAT_SYSCALL_DEFINE2 ( getitimer , int , which ,
struct compat_itimerval __user * , it )
2005-04-17 02:20:36 +04:00
{
struct itimerval kit ;
int error ;
error = do_getitimer ( which , & kit ) ;
if ( ! error & & put_compat_itimerval ( it , & kit ) )
error = - EFAULT ;
return error ;
}
2012-12-25 02:28:40 +04:00
COMPAT_SYSCALL_DEFINE3 ( setitimer , int , which ,
struct compat_itimerval __user * , in ,
struct compat_itimerval __user * , out )
2005-04-17 02:20:36 +04:00
{
struct itimerval kin , kout ;
int error ;
if ( in ) {
if ( get_compat_itimerval ( & kin , in ) )
return - EFAULT ;
} else
memset ( & kin , 0 , sizeof ( kin ) ) ;
error = do_setitimer ( which , & kin , out ? & kout : NULL ) ;
if ( error | | ! out )
return error ;
if ( put_compat_itimerval ( out , & kout ) )
return - EFAULT ;
return 0 ;
}
timers: fix itimer/many thread hang
Overview
This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together
with the help of Roland McGrath, the owner and original writer of this code.
The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads. It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.
This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."
Code Changes
This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine. (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.) To do this, at each tick we now update fields in
signal_struct as well as task_struct. The run_posix_cpu_timers() function
uses those fields to make its decisions.
We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:
struct thread_group_cputime {
struct task_cputime totals;
};
struct thread_group_cputime {
struct task_cputime *totals;
};
We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers). The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends. In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention). For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu(). The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().
We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel. The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields. The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures. The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated. The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU. Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.
Non-SMP operation is trivial and will not be mentioned further.
The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().
All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.
Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away. All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline. When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.
Performance
The fix appears not to add significant overhead to existing operations. It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below). Overall it's a wash except in those
two cases.
I've since done somewhat more involved testing on a dual-core Opteron system.
Case 1: With no itimer running, for a test with 100,000 threads, the fixed
kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
all of which was spent in the system. There were twice as many
voluntary context switches with the fix as without it.
Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
an unmodified kernel can handle), the fixed kernel ran the test in
eight percent of the time (5.8 seconds as opposed to 70 seconds) and
had better tick accuracy (.012 seconds per tick as opposed to .023
seconds per tick).
Case 3: A 4000-thread test with an initial timer tick of .01 second and an
interval of 10,000 seconds (i.e. a timer that ticks only once) had
very nearly the same performance in both cases: 6.3 seconds elapsed
for the fixed kernel versus 5.5 seconds for the unfixed kernel.
With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.
Since the fix affected the rlimit code, I also tested soft and hard CPU limits.
Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
running), the modified kernel was very slightly favored in that while
it killed the process in 19.997 seconds of CPU time (5.002 seconds of
wall time), only .003 seconds of that was system time, the rest was
user time. The unmodified kernel killed the process in 20.001 seconds
of CPU (5.014 seconds of wall time) of which .016 seconds was system
time. Really, though, the results were too close to call. The results
were essentially the same with no itimer running.
Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
(where the hard limit would never be reached) and an itimer running,
the modified kernel exhibited worse tick accuracy than the unmodified
kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise,
performance was almost indistinguishable. With no itimer running this
test exhibited virtually identical behavior and times in both cases.
In times past I did some limited performance testing. those results are below.
On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds. Performance with eight, four and one
thread were comparable. Interestingly, the timer ticks with the fix seemed
more accurate: The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick. Both cases were configured for an interval of
0.01 seconds. Again, the other tests were comparable. Each thread in this
test computed the primes up to 25,000,000.
I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix. In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable). System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite
accurate. There is obviously no comparable test without the fix.
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-12 20:54:39 +04:00
static compat_clock_t clock_t_to_compat_clock_t ( clock_t x )
{
return compat_jiffies_to_clock_t ( clock_t_to_jiffies ( x ) ) ;
}
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE1 ( times , struct compat_tms __user * , tbuf )
2005-04-17 02:20:36 +04:00
{
if ( tbuf ) {
timers: fix itimer/many thread hang
Overview
This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together
with the help of Roland McGrath, the owner and original writer of this code.
The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads. It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.
This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."
Code Changes
This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine. (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.) To do this, at each tick we now update fields in
signal_struct as well as task_struct. The run_posix_cpu_timers() function
uses those fields to make its decisions.
We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:
struct thread_group_cputime {
struct task_cputime totals;
};
struct thread_group_cputime {
struct task_cputime *totals;
};
We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers). The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends. In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention). For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu(). The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().
We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel. The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields. The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures. The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated. The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU. Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.
Non-SMP operation is trivial and will not be mentioned further.
The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().
All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.
Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away. All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline. When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.
Performance
The fix appears not to add significant overhead to existing operations. It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below). Overall it's a wash except in those
two cases.
I've since done somewhat more involved testing on a dual-core Opteron system.
Case 1: With no itimer running, for a test with 100,000 threads, the fixed
kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
all of which was spent in the system. There were twice as many
voluntary context switches with the fix as without it.
Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
an unmodified kernel can handle), the fixed kernel ran the test in
eight percent of the time (5.8 seconds as opposed to 70 seconds) and
had better tick accuracy (.012 seconds per tick as opposed to .023
seconds per tick).
Case 3: A 4000-thread test with an initial timer tick of .01 second and an
interval of 10,000 seconds (i.e. a timer that ticks only once) had
very nearly the same performance in both cases: 6.3 seconds elapsed
for the fixed kernel versus 5.5 seconds for the unfixed kernel.
With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.
Since the fix affected the rlimit code, I also tested soft and hard CPU limits.
Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
running), the modified kernel was very slightly favored in that while
it killed the process in 19.997 seconds of CPU time (5.002 seconds of
wall time), only .003 seconds of that was system time, the rest was
user time. The unmodified kernel killed the process in 20.001 seconds
of CPU (5.014 seconds of wall time) of which .016 seconds was system
time. Really, though, the results were too close to call. The results
were essentially the same with no itimer running.
Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
(where the hard limit would never be reached) and an itimer running,
the modified kernel exhibited worse tick accuracy than the unmodified
kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise,
performance was almost indistinguishable. With no itimer running this
test exhibited virtually identical behavior and times in both cases.
In times past I did some limited performance testing. those results are below.
On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds. Performance with eight, four and one
thread were comparable. Interestingly, the timer ticks with the fix seemed
more accurate: The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick. Both cases were configured for an interval of
0.01 seconds. Again, the other tests were comparable. Each thread in this
test computed the primes up to 25,000,000.
I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix. In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable). System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite
accurate. There is obviously no comparable test without the fix.
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-12 20:54:39 +04:00
struct tms tms ;
2005-04-17 02:20:36 +04:00
struct compat_tms tmp ;
timers: fix itimer/many thread hang
Overview
This patch reworks the handling of POSIX CPU timers, including the
ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together
with the help of Roland McGrath, the owner and original writer of this code.
The problem we ran into, and the reason for this rework, has to do with using
a profiling timer in a process with a large number of threads. It appears
that the performance of the old implementation of run_posix_cpu_timers() was
at least O(n*3) (where "n" is the number of threads in a process) or worse.
Everything is fine with an increasing number of threads until the time taken
for that routine to run becomes the same as or greater than the tick time, at
which point things degrade rather quickly.
This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF."
Code Changes
This rework corrects the implementation of run_posix_cpu_timers() to make it
run in constant time for a particular machine. (Performance may vary between
one machine and another depending upon whether the kernel is built as single-
or multiprocessor and, in the latter case, depending upon the number of
running processors.) To do this, at each tick we now update fields in
signal_struct as well as task_struct. The run_posix_cpu_timers() function
uses those fields to make its decisions.
We define a new structure, "task_cputime," to contain user, system and
scheduler times and use these in appropriate places:
struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
};
This is included in the structure "thread_group_cputime," which is a new
substructure of signal_struct and which varies for uniprocessor versus
multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as
a simple substructure, while for multiprocessor kernels it is a pointer:
struct thread_group_cputime {
struct task_cputime totals;
};
struct thread_group_cputime {
struct task_cputime *totals;
};
We also add a new task_cputime substructure directly to signal_struct, to
cache the earliest expiration of process-wide timers, and task_cputime also
replaces the it_*_expires fields of task_struct (used for earliest expiration
of thread timers). The "thread_group_cputime" structure contains process-wide
timers that are updated via account_user_time() and friends. In the non-SMP
case the structure is a simple aggregator; unfortunately in the SMP case that
simplicity was not achievable due to cache-line contention between CPUs (in
one measured case performance was actually _worse_ on a 16-cpu system than
the same test on a 4-cpu system, due to this contention). For SMP, the
thread_group_cputime counters are maintained as a per-cpu structure allocated
using alloc_percpu(). The timer functions update only the timer field in
the structure corresponding to the running CPU, obtained using per_cpu_ptr().
We define a set of inline functions in sched.h that we use to maintain the
thread_group_cputime structure and hide the differences between UP and SMP
implementations from the rest of the kernel. The thread_group_cputime_init()
function initializes the thread_group_cputime structure for the given task.
The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the
out-of-line function thread_group_cputime_alloc_smp() to allocate and fill
in the per-cpu structures and fields. The thread_group_cputime_free()
function, also a no-op for UP, in SMP frees the per-cpu structures. The
thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls
thread_group_cputime_alloc() if the per-cpu structures haven't yet been
allocated. The thread_group_cputime() function fills the task_cputime
structure it is passed with the contents of the thread_group_cputime fields;
in UP it's that simple but in SMP it must also safely check that tsk->signal
is non-NULL (if it is it just uses the appropriate fields of task_struct) and,
if so, sums the per-cpu values for each online CPU. Finally, the three
functions account_group_user_time(), account_group_system_time() and
account_group_exec_runtime() are used by timer functions to update the
respective fields of the thread_group_cputime structure.
Non-SMP operation is trivial and will not be mentioned further.
The per-cpu structure is always allocated when a task creates its first new
thread, via a call to thread_group_cputime_clone_thread() from copy_signal().
It is freed at process exit via a call to thread_group_cputime_free() from
cleanup_signal().
All functions that formerly summed utime/stime/sum_sched_runtime values from
from all threads in the thread group now use thread_group_cputime() to
snapshot the values in the thread_group_cputime structure or the values in
the task structure itself if the per-cpu structure hasn't been allocated.
Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit.
The run_posix_cpu_timers() function has been split into a fast path and a
slow path; the former safely checks whether there are any expired thread
timers and, if not, just returns, while the slow path does the heavy lifting.
With the dedicated thread group fields, timers are no longer "rebalanced" and
the process_timer_rebalance() function and related code has gone away. All
summing loops are gone and all code that used them now uses the
thread_group_cputime() inline. When process-wide timers are set, the new
task_cputime structure in signal_struct is used to cache the earliest
expiration; this is checked in the fast path.
Performance
The fix appears not to add significant overhead to existing operations. It
generally performs the same as the current code except in two cases, one in
which it performs slightly worse (Case 5 below) and one in which it performs
very significantly better (Case 2 below). Overall it's a wash except in those
two cases.
I've since done somewhat more involved testing on a dual-core Opteron system.
Case 1: With no itimer running, for a test with 100,000 threads, the fixed
kernel took 1428.5 seconds, 513 seconds more than the unfixed system,
all of which was spent in the system. There were twice as many
voluntary context switches with the fix as without it.
Case 2: With an itimer running at .01 second ticks and 4000 threads (the most
an unmodified kernel can handle), the fixed kernel ran the test in
eight percent of the time (5.8 seconds as opposed to 70 seconds) and
had better tick accuracy (.012 seconds per tick as opposed to .023
seconds per tick).
Case 3: A 4000-thread test with an initial timer tick of .01 second and an
interval of 10,000 seconds (i.e. a timer that ticks only once) had
very nearly the same performance in both cases: 6.3 seconds elapsed
for the fixed kernel versus 5.5 seconds for the unfixed kernel.
With fewer threads (eight in these tests), the Case 1 test ran in essentially
the same time on both the modified and unmodified kernels (5.2 seconds versus
5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds
versus 5.4 seconds but again with much better tick accuracy, .013 seconds per
tick versus .025 seconds per tick for the unmodified kernel.
Since the fix affected the rlimit code, I also tested soft and hard CPU limits.
Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer
running), the modified kernel was very slightly favored in that while
it killed the process in 19.997 seconds of CPU time (5.002 seconds of
wall time), only .003 seconds of that was system time, the rest was
user time. The unmodified kernel killed the process in 20.001 seconds
of CPU (5.014 seconds of wall time) of which .016 seconds was system
time. Really, though, the results were too close to call. The results
were essentially the same with no itimer running.
Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds
(where the hard limit would never be reached) and an itimer running,
the modified kernel exhibited worse tick accuracy than the unmodified
kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise,
performance was almost indistinguishable. With no itimer running this
test exhibited virtually identical behavior and times in both cases.
In times past I did some limited performance testing. those results are below.
On a four-cpu Opteron system without this fix, a sixteen-thread test executed
in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On
the same system with the fix, user and elapsed time were about the same, but
system time dropped to 0.007 seconds. Performance with eight, four and one
thread were comparable. Interestingly, the timer ticks with the fix seemed
more accurate: The sixteen-thread test with the fix received 149543 ticks
for 0.024 seconds per tick, while the same test without the fix received 58720
for 0.061 seconds per tick. Both cases were configured for an interval of
0.01 seconds. Again, the other tests were comparable. Each thread in this
test computed the primes up to 25,000,000.
I also did a test with a large number of threads, 100,000 threads, which is
impossible without the fix. In this case each thread computed the primes only
up to 10,000 (to make the runtime manageable). System time dominated, at
1546.968 seconds out of a total 2176.906 seconds (giving a user time of
629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite
accurate. There is obviously no comparable test without the fix.
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-12 20:54:39 +04:00
do_sys_times ( & tms ) ;
/* Convert our struct tms to the compat version. */
tmp . tms_utime = clock_t_to_compat_clock_t ( tms . tms_utime ) ;
tmp . tms_stime = clock_t_to_compat_clock_t ( tms . tms_stime ) ;
tmp . tms_cutime = clock_t_to_compat_clock_t ( tms . tms_cutime ) ;
tmp . tms_cstime = clock_t_to_compat_clock_t ( tms . tms_cstime ) ;
2005-04-17 02:20:36 +04:00
if ( copy_to_user ( tbuf , & tmp , sizeof ( tmp ) ) )
return - EFAULT ;
}
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force_successful_syscall_return ( ) ;
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return compat_jiffies_to_clock_t ( jiffies ) ;
}
2011-05-09 21:12:30 +04:00
# ifdef __ARCH_WANT_SYS_SIGPENDING
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/*
* Assumption : old_sigset_t and compat_old_sigset_t are both
* types that can be passed to put_user ( ) / get_user ( ) .
*/
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE1 ( sigpending , compat_old_sigset_t __user * , set )
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{
old_sigset_t s ;
long ret ;
mm_segment_t old_fs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
ret = sys_sigpending ( ( old_sigset_t __user * ) & s ) ;
set_fs ( old_fs ) ;
if ( ret = = 0 )
ret = put_user ( s , set ) ;
return ret ;
}
2011-05-09 21:12:30 +04:00
# endif
# ifdef __ARCH_WANT_SYS_SIGPROCMASK
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/*
* sys_sigprocmask SIG_SETMASK sets the first ( compat ) word of the
* blocked set of signals to the supplied signal set
*/
static inline void compat_sig_setmask ( sigset_t * blocked , compat_sigset_word set )
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{
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memcpy ( blocked - > sig , & set , sizeof ( set ) ) ;
}
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2012-11-26 04:41:01 +04:00
COMPAT_SYSCALL_DEFINE3 ( sigprocmask , int , how ,
compat_old_sigset_t __user * , nset ,
compat_old_sigset_t __user * , oset )
2012-05-10 17:04:36 +04:00
{
old_sigset_t old_set , new_set ;
sigset_t new_blocked ;
old_set = current - > blocked . sig [ 0 ] ;
if ( nset ) {
if ( get_user ( new_set , nset ) )
return - EFAULT ;
new_set & = ~ ( sigmask ( SIGKILL ) | sigmask ( SIGSTOP ) ) ;
new_blocked = current - > blocked ;
switch ( how ) {
case SIG_BLOCK :
sigaddsetmask ( & new_blocked , new_set ) ;
break ;
case SIG_UNBLOCK :
sigdelsetmask ( & new_blocked , new_set ) ;
break ;
case SIG_SETMASK :
compat_sig_setmask ( & new_blocked , new_set ) ;
break ;
default :
return - EINVAL ;
}
set_current_blocked ( & new_blocked ) ;
}
if ( oset ) {
if ( put_user ( old_set , oset ) )
return - EFAULT ;
}
return 0 ;
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}
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# endif
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COMPAT_SYSCALL_DEFINE2 ( setrlimit , unsigned int , resource ,
struct compat_rlimit __user * , rlim )
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{
struct rlimit r ;
if ( ! access_ok ( VERIFY_READ , rlim , sizeof ( * rlim ) ) | |
__get_user ( r . rlim_cur , & rlim - > rlim_cur ) | |
__get_user ( r . rlim_max , & rlim - > rlim_max ) )
return - EFAULT ;
if ( r . rlim_cur = = COMPAT_RLIM_INFINITY )
r . rlim_cur = RLIM_INFINITY ;
if ( r . rlim_max = = COMPAT_RLIM_INFINITY )
r . rlim_max = RLIM_INFINITY ;
2010-05-04 13:28:25 +04:00
return do_prlimit ( current , resource , & r , NULL ) ;
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}
# ifdef COMPAT_RLIM_OLD_INFINITY
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COMPAT_SYSCALL_DEFINE2 ( old_getrlimit , unsigned int , resource ,
struct compat_rlimit __user * , rlim )
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{
struct rlimit r ;
int ret ;
mm_segment_t old_fs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
2014-02-03 05:57:28 +04:00
ret = sys_old_getrlimit ( resource , ( struct rlimit __user * ) & r ) ;
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set_fs ( old_fs ) ;
if ( ! ret ) {
if ( r . rlim_cur > COMPAT_RLIM_OLD_INFINITY )
r . rlim_cur = COMPAT_RLIM_INFINITY ;
if ( r . rlim_max > COMPAT_RLIM_OLD_INFINITY )
r . rlim_max = COMPAT_RLIM_INFINITY ;
if ( ! access_ok ( VERIFY_WRITE , rlim , sizeof ( * rlim ) ) | |
__put_user ( r . rlim_cur , & rlim - > rlim_cur ) | |
__put_user ( r . rlim_max , & rlim - > rlim_max ) )
return - EFAULT ;
}
return ret ;
}
# endif
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COMPAT_SYSCALL_DEFINE2 ( getrlimit , unsigned int , resource ,
struct compat_rlimit __user * , rlim )
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{
struct rlimit r ;
int ret ;
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ret = do_prlimit ( current , resource , NULL , & r ) ;
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if ( ! ret ) {
if ( r . rlim_cur > COMPAT_RLIM_INFINITY )
r . rlim_cur = COMPAT_RLIM_INFINITY ;
if ( r . rlim_max > COMPAT_RLIM_INFINITY )
r . rlim_max = COMPAT_RLIM_INFINITY ;
if ( ! access_ok ( VERIFY_WRITE , rlim , sizeof ( * rlim ) ) | |
__put_user ( r . rlim_cur , & rlim - > rlim_cur ) | |
__put_user ( r . rlim_max , & rlim - > rlim_max ) )
return - EFAULT ;
}
return ret ;
}
int put_compat_rusage ( const struct rusage * r , struct compat_rusage __user * ru )
{
if ( ! access_ok ( VERIFY_WRITE , ru , sizeof ( * ru ) ) | |
__put_user ( r - > ru_utime . tv_sec , & ru - > ru_utime . tv_sec ) | |
__put_user ( r - > ru_utime . tv_usec , & ru - > ru_utime . tv_usec ) | |
__put_user ( r - > ru_stime . tv_sec , & ru - > ru_stime . tv_sec ) | |
__put_user ( r - > ru_stime . tv_usec , & ru - > ru_stime . tv_usec ) | |
__put_user ( r - > ru_maxrss , & ru - > ru_maxrss ) | |
__put_user ( r - > ru_ixrss , & ru - > ru_ixrss ) | |
__put_user ( r - > ru_idrss , & ru - > ru_idrss ) | |
__put_user ( r - > ru_isrss , & ru - > ru_isrss ) | |
__put_user ( r - > ru_minflt , & ru - > ru_minflt ) | |
__put_user ( r - > ru_majflt , & ru - > ru_majflt ) | |
__put_user ( r - > ru_nswap , & ru - > ru_nswap ) | |
__put_user ( r - > ru_inblock , & ru - > ru_inblock ) | |
__put_user ( r - > ru_oublock , & ru - > ru_oublock ) | |
__put_user ( r - > ru_msgsnd , & ru - > ru_msgsnd ) | |
__put_user ( r - > ru_msgrcv , & ru - > ru_msgrcv ) | |
__put_user ( r - > ru_nsignals , & ru - > ru_nsignals ) | |
__put_user ( r - > ru_nvcsw , & ru - > ru_nvcsw ) | |
__put_user ( r - > ru_nivcsw , & ru - > ru_nivcsw ) )
return - EFAULT ;
return 0 ;
}
2012-12-23 23:56:40 +04:00
COMPAT_SYSCALL_DEFINE4 ( wait4 ,
compat_pid_t , pid ,
compat_uint_t __user * , stat_addr ,
int , options ,
struct compat_rusage __user * , ru )
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{
if ( ! ru ) {
return sys_wait4 ( pid , stat_addr , options , NULL ) ;
} else {
struct rusage r ;
int ret ;
unsigned int status ;
mm_segment_t old_fs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
ret = sys_wait4 ( pid ,
( stat_addr ?
( unsigned int __user * ) & status : NULL ) ,
options , ( struct rusage __user * ) & r ) ;
set_fs ( old_fs ) ;
if ( ret > 0 ) {
if ( put_compat_rusage ( & r , ru ) )
return - EFAULT ;
if ( stat_addr & & put_user ( status , stat_addr ) )
return - EFAULT ;
}
return ret ;
}
}
2012-12-23 23:56:40 +04:00
COMPAT_SYSCALL_DEFINE5 ( waitid ,
int , which , compat_pid_t , pid ,
struct compat_siginfo __user * , uinfo , int , options ,
struct compat_rusage __user * , uru )
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{
siginfo_t info ;
struct rusage ru ;
long ret ;
mm_segment_t old_fs = get_fs ( ) ;
memset ( & info , 0 , sizeof ( info ) ) ;
set_fs ( KERNEL_DS ) ;
ret = sys_waitid ( which , pid , ( siginfo_t __user * ) & info , options ,
uru ? ( struct rusage __user * ) & ru : NULL ) ;
set_fs ( old_fs ) ;
if ( ( ret < 0 ) | | ( info . si_signo = = 0 ) )
return ret ;
if ( uru ) {
2012-12-24 08:14:49 +04:00
/* sys_waitid() overwrites everything in ru */
if ( COMPAT_USE_64BIT_TIME )
ret = copy_to_user ( uru , & ru , sizeof ( ru ) ) ;
else
ret = put_compat_rusage ( & ru , uru ) ;
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if ( ret )
2013-02-22 04:41:57 +04:00
return - EFAULT ;
2005-04-17 02:20:36 +04:00
}
BUG_ON ( info . si_code & __SI_MASK ) ;
info . si_code | = __SI_CHLD ;
return copy_siginfo_to_user32 ( uinfo , & info ) ;
}
static int compat_get_user_cpu_mask ( compat_ulong_t __user * user_mask_ptr ,
2009-01-01 02:42:24 +03:00
unsigned len , struct cpumask * new_mask )
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{
unsigned long * k ;
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if ( len < cpumask_size ( ) )
memset ( new_mask , 0 , cpumask_size ( ) ) ;
else if ( len > cpumask_size ( ) )
len = cpumask_size ( ) ;
2005-04-17 02:20:36 +04:00
2009-01-01 02:42:24 +03:00
k = cpumask_bits ( new_mask ) ;
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return compat_get_bitmap ( k , user_mask_ptr , len * 8 ) ;
}
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE3 ( sched_setaffinity , compat_pid_t , pid ,
unsigned int , len ,
compat_ulong_t __user * , user_mask_ptr )
2005-04-17 02:20:36 +04:00
{
2009-01-01 02:42:24 +03:00
cpumask_var_t new_mask ;
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int retval ;
2009-01-01 02:42:24 +03:00
if ( ! alloc_cpumask_var ( & new_mask , GFP_KERNEL ) )
return - ENOMEM ;
retval = compat_get_user_cpu_mask ( user_mask_ptr , len , new_mask ) ;
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if ( retval )
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goto out ;
2005-04-17 02:20:36 +04:00
2009-01-01 02:42:24 +03:00
retval = sched_setaffinity ( pid , new_mask ) ;
out :
free_cpumask_var ( new_mask ) ;
return retval ;
2005-04-17 02:20:36 +04:00
}
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE3 ( sched_getaffinity , compat_pid_t , pid , unsigned int , len ,
compat_ulong_t __user * , user_mask_ptr )
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{
int ret ;
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cpumask_var_t mask ;
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2010-05-19 04:37:41 +04:00
if ( ( len * BITS_PER_BYTE ) < nr_cpu_ids )
return - EINVAL ;
if ( len & ( sizeof ( compat_ulong_t ) - 1 ) )
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return - EINVAL ;
2009-01-01 02:42:24 +03:00
if ( ! alloc_cpumask_var ( & mask , GFP_KERNEL ) )
return - ENOMEM ;
ret = sched_getaffinity ( pid , mask ) ;
2010-05-19 04:37:41 +04:00
if ( ret = = 0 ) {
size_t retlen = min_t ( size_t , len , cpumask_size ( ) ) ;
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2010-05-19 04:37:41 +04:00
if ( compat_put_bitmap ( user_mask_ptr , cpumask_bits ( mask ) , retlen * 8 ) )
ret = - EFAULT ;
else
ret = retlen ;
}
2009-01-01 02:42:24 +03:00
free_cpumask_var ( mask ) ;
2010-05-19 04:37:41 +04:00
2009-01-01 02:42:24 +03:00
return ret ;
2005-04-17 02:20:36 +04:00
}
2007-05-11 09:23:18 +04:00
int get_compat_itimerspec ( struct itimerspec * dst ,
const struct compat_itimerspec __user * src )
2007-10-18 14:06:09 +04:00
{
2014-02-02 06:54:11 +04:00
if ( __compat_get_timespec ( & dst - > it_interval , & src - > it_interval ) | |
__compat_get_timespec ( & dst - > it_value , & src - > it_value ) )
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return - EFAULT ;
return 0 ;
2007-10-18 14:06:09 +04:00
}
2005-04-17 02:20:36 +04:00
2007-05-11 09:23:18 +04:00
int put_compat_itimerspec ( struct compat_itimerspec __user * dst ,
const struct itimerspec * src )
2007-10-18 14:06:09 +04:00
{
2014-02-02 06:54:11 +04:00
if ( __compat_put_timespec ( & src - > it_interval , & dst - > it_interval ) | |
__compat_put_timespec ( & src - > it_value , & dst - > it_value ) )
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return - EFAULT ;
return 0 ;
2007-10-18 14:06:09 +04:00
}
2005-04-17 02:20:36 +04:00
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE3 ( timer_create , clockid_t , which_clock ,
struct compat_sigevent __user * , timer_event_spec ,
timer_t __user * , created_timer_id )
2006-01-10 07:52:08 +03:00
{
struct sigevent __user * event = NULL ;
if ( timer_event_spec ) {
struct sigevent kevent ;
event = compat_alloc_user_space ( sizeof ( * event ) ) ;
if ( get_compat_sigevent ( & kevent , timer_event_spec ) | |
copy_to_user ( event , & kevent , sizeof ( * event ) ) )
return - EFAULT ;
}
return sys_timer_create ( which_clock , event , created_timer_id ) ;
}
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE4 ( timer_settime , timer_t , timer_id , int , flags ,
struct compat_itimerspec __user * , new ,
struct compat_itimerspec __user * , old )
2007-10-18 14:06:09 +04:00
{
2005-04-17 02:20:36 +04:00
long err ;
mm_segment_t oldfs ;
struct itimerspec newts , oldts ;
if ( ! new )
return - EINVAL ;
if ( get_compat_itimerspec ( & newts , new ) )
2007-10-18 14:06:09 +04:00
return - EFAULT ;
2005-04-17 02:20:36 +04:00
oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
err = sys_timer_settime ( timer_id , flags ,
( struct itimerspec __user * ) & newts ,
( struct itimerspec __user * ) & oldts ) ;
2007-10-18 14:06:09 +04:00
set_fs ( oldfs ) ;
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if ( ! err & & old & & put_compat_itimerspec ( old , & oldts ) )
return - EFAULT ;
return err ;
2007-10-18 14:06:09 +04:00
}
2005-04-17 02:20:36 +04:00
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE2 ( timer_gettime , timer_t , timer_id ,
struct compat_itimerspec __user * , setting )
2007-10-18 14:06:09 +04:00
{
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long err ;
mm_segment_t oldfs ;
2007-10-18 14:06:09 +04:00
struct itimerspec ts ;
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oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
err = sys_timer_gettime ( timer_id ,
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( struct itimerspec __user * ) & ts ) ;
set_fs ( oldfs ) ;
2005-04-17 02:20:36 +04:00
if ( ! err & & put_compat_itimerspec ( setting , & ts ) )
return - EFAULT ;
return err ;
2007-10-18 14:06:09 +04:00
}
2005-04-17 02:20:36 +04:00
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE2 ( clock_settime , clockid_t , which_clock ,
struct compat_timespec __user * , tp )
2005-04-17 02:20:36 +04:00
{
long err ;
mm_segment_t oldfs ;
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struct timespec ts ;
2005-04-17 02:20:36 +04:00
2014-02-02 06:54:11 +04:00
if ( compat_get_timespec ( & ts , tp ) )
2007-10-18 14:06:09 +04:00
return - EFAULT ;
2005-04-17 02:20:36 +04:00
oldfs = get_fs ( ) ;
2007-10-18 14:06:09 +04:00
set_fs ( KERNEL_DS ) ;
2005-04-17 02:20:36 +04:00
err = sys_clock_settime ( which_clock ,
( struct timespec __user * ) & ts ) ;
set_fs ( oldfs ) ;
return err ;
2007-10-18 14:06:09 +04:00
}
2005-04-17 02:20:36 +04:00
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE2 ( clock_gettime , clockid_t , which_clock ,
struct compat_timespec __user * , tp )
2005-04-17 02:20:36 +04:00
{
long err ;
mm_segment_t oldfs ;
2007-10-18 14:06:09 +04:00
struct timespec ts ;
2005-04-17 02:20:36 +04:00
oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
err = sys_clock_gettime ( which_clock ,
( struct timespec __user * ) & ts ) ;
set_fs ( oldfs ) ;
2014-02-02 06:54:11 +04:00
if ( ! err & & compat_put_timespec ( & ts , tp ) )
2007-10-18 14:06:09 +04:00
return - EFAULT ;
2005-04-17 02:20:36 +04:00
return err ;
2007-10-18 14:06:09 +04:00
}
2005-04-17 02:20:36 +04:00
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE2 ( clock_adjtime , clockid_t , which_clock ,
struct compat_timex __user * , utp )
2011-02-01 16:52:26 +03:00
{
struct timex txc ;
mm_segment_t oldfs ;
int err , ret ;
err = compat_get_timex ( & txc , utp ) ;
if ( err )
return err ;
oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
ret = sys_clock_adjtime ( which_clock , ( struct timex __user * ) & txc ) ;
set_fs ( oldfs ) ;
err = compat_put_timex ( utp , & txc ) ;
if ( err )
return err ;
return ret ;
}
2014-03-03 19:11:13 +04:00
COMPAT_SYSCALL_DEFINE2 ( clock_getres , clockid_t , which_clock ,
struct compat_timespec __user * , tp )
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{
long err ;
mm_segment_t oldfs ;
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struct timespec ts ;
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oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
err = sys_clock_getres ( which_clock ,
( struct timespec __user * ) & ts ) ;
set_fs ( oldfs ) ;
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if ( ! err & & tp & & compat_put_timespec ( & ts , tp ) )
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return - EFAULT ;
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return err ;
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}
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static long compat_clock_nanosleep_restart ( struct restart_block * restart )
{
long err ;
mm_segment_t oldfs ;
struct timespec tu ;
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struct compat_timespec __user * rmtp = restart - > nanosleep . compat_rmtp ;
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restart - > nanosleep . rmtp = ( struct timespec __user * ) & tu ;
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oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
err = clock_nanosleep_restart ( restart ) ;
set_fs ( oldfs ) ;
if ( ( err = = - ERESTART_RESTARTBLOCK ) & & rmtp & &
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compat_put_timespec ( & tu , rmtp ) )
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return - EFAULT ;
if ( err = = - ERESTART_RESTARTBLOCK ) {
restart - > fn = compat_clock_nanosleep_restart ;
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restart - > nanosleep . compat_rmtp = rmtp ;
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}
return err ;
}
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COMPAT_SYSCALL_DEFINE4 ( clock_nanosleep , clockid_t , which_clock , int , flags ,
struct compat_timespec __user * , rqtp ,
struct compat_timespec __user * , rmtp )
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{
long err ;
mm_segment_t oldfs ;
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struct timespec in , out ;
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struct restart_block * restart ;
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if ( compat_get_timespec ( & in , rqtp ) )
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return - EFAULT ;
oldfs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
err = sys_clock_nanosleep ( which_clock , flags ,
( struct timespec __user * ) & in ,
( struct timespec __user * ) & out ) ;
set_fs ( oldfs ) ;
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if ( ( err = = - ERESTART_RESTARTBLOCK ) & & rmtp & &
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compat_put_timespec ( & out , rmtp ) )
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return - EFAULT ;
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if ( err = = - ERESTART_RESTARTBLOCK ) {
restart = & current_thread_info ( ) - > restart_block ;
restart - > fn = compat_clock_nanosleep_restart ;
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restart - > nanosleep . compat_rmtp = rmtp ;
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}
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return err ;
}
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/*
* We currently only need the following fields from the sigevent
* structure : sigev_value , sigev_signo , sig_notify and ( sometimes
* sigev_notify_thread_id ) . The others are handled in user mode .
* We also assume that copying sigev_value . sival_int is sufficient
* to keep all the bits of sigev_value . sival_ptr intact .
*/
int get_compat_sigevent ( struct sigevent * event ,
const struct compat_sigevent __user * u_event )
{
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memset ( event , 0 , sizeof ( * event ) ) ;
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return ( ! access_ok ( VERIFY_READ , u_event , sizeof ( * u_event ) ) | |
__get_user ( event - > sigev_value . sival_int ,
& u_event - > sigev_value . sival_int ) | |
__get_user ( event - > sigev_signo , & u_event - > sigev_signo ) | |
__get_user ( event - > sigev_notify , & u_event - > sigev_notify ) | |
__get_user ( event - > sigev_notify_thread_id ,
& u_event - > sigev_notify_thread_id ) )
? - EFAULT : 0 ;
}
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long compat_get_bitmap ( unsigned long * mask , const compat_ulong_t __user * umask ,
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unsigned long bitmap_size )
{
int i , j ;
unsigned long m ;
compat_ulong_t um ;
unsigned long nr_compat_longs ;
/* align bitmap up to nearest compat_long_t boundary */
bitmap_size = ALIGN ( bitmap_size , BITS_PER_COMPAT_LONG ) ;
if ( ! access_ok ( VERIFY_READ , umask , bitmap_size / 8 ) )
return - EFAULT ;
nr_compat_longs = BITS_TO_COMPAT_LONGS ( bitmap_size ) ;
for ( i = 0 ; i < BITS_TO_LONGS ( bitmap_size ) ; i + + ) {
m = 0 ;
for ( j = 0 ; j < sizeof ( m ) / sizeof ( um ) ; j + + ) {
/*
* We dont want to read past the end of the userspace
* bitmap . We must however ensure the end of the
* kernel bitmap is zeroed .
*/
if ( nr_compat_longs - - > 0 ) {
if ( __get_user ( um , umask ) )
return - EFAULT ;
} else {
um = 0 ;
}
umask + + ;
m | = ( long ) um < < ( j * BITS_PER_COMPAT_LONG ) ;
}
* mask + + = m ;
}
return 0 ;
}
long compat_put_bitmap ( compat_ulong_t __user * umask , unsigned long * mask ,
unsigned long bitmap_size )
{
int i , j ;
unsigned long m ;
compat_ulong_t um ;
unsigned long nr_compat_longs ;
/* align bitmap up to nearest compat_long_t boundary */
bitmap_size = ALIGN ( bitmap_size , BITS_PER_COMPAT_LONG ) ;
if ( ! access_ok ( VERIFY_WRITE , umask , bitmap_size / 8 ) )
return - EFAULT ;
nr_compat_longs = BITS_TO_COMPAT_LONGS ( bitmap_size ) ;
for ( i = 0 ; i < BITS_TO_LONGS ( bitmap_size ) ; i + + ) {
m = * mask + + ;
for ( j = 0 ; j < sizeof ( m ) / sizeof ( um ) ; j + + ) {
um = m ;
/*
* We dont want to write past the end of the userspace
* bitmap .
*/
if ( nr_compat_longs - - > 0 ) {
if ( __put_user ( um , umask ) )
return - EFAULT ;
}
umask + + ;
m > > = 4 * sizeof ( um ) ;
m > > = 4 * sizeof ( um ) ;
}
}
return 0 ;
}
void
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sigset_from_compat ( sigset_t * set , const compat_sigset_t * compat )
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{
switch ( _NSIG_WORDS ) {
case 4 : set - > sig [ 3 ] = compat - > sig [ 6 ] | ( ( ( long ) compat - > sig [ 7 ] ) < < 32 ) ;
case 3 : set - > sig [ 2 ] = compat - > sig [ 4 ] | ( ( ( long ) compat - > sig [ 5 ] ) < < 32 ) ;
case 2 : set - > sig [ 1 ] = compat - > sig [ 2 ] | ( ( ( long ) compat - > sig [ 3 ] ) < < 32 ) ;
case 1 : set - > sig [ 0 ] = compat - > sig [ 0 ] | ( ( ( long ) compat - > sig [ 1 ] ) < < 32 ) ;
}
}
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EXPORT_SYMBOL_GPL ( sigset_from_compat ) ;
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void
sigset_to_compat ( compat_sigset_t * compat , const sigset_t * set )
{
switch ( _NSIG_WORDS ) {
case 4 : compat - > sig [ 7 ] = ( set - > sig [ 3 ] > > 32 ) ; compat - > sig [ 6 ] = set - > sig [ 3 ] ;
case 3 : compat - > sig [ 5 ] = ( set - > sig [ 2 ] > > 32 ) ; compat - > sig [ 4 ] = set - > sig [ 2 ] ;
case 2 : compat - > sig [ 3 ] = ( set - > sig [ 1 ] > > 32 ) ; compat - > sig [ 2 ] = set - > sig [ 1 ] ;
case 1 : compat - > sig [ 1 ] = ( set - > sig [ 0 ] > > 32 ) ; compat - > sig [ 0 ] = set - > sig [ 0 ] ;
}
}
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COMPAT_SYSCALL_DEFINE4 ( rt_sigtimedwait , compat_sigset_t __user * , uthese ,
struct compat_siginfo __user * , uinfo ,
struct compat_timespec __user * , uts , compat_size_t , sigsetsize )
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{
compat_sigset_t s32 ;
sigset_t s ;
struct timespec t ;
siginfo_t info ;
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long ret ;
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if ( sigsetsize ! = sizeof ( sigset_t ) )
return - EINVAL ;
if ( copy_from_user ( & s32 , uthese , sizeof ( compat_sigset_t ) ) )
return - EFAULT ;
sigset_from_compat ( & s , & s32 ) ;
if ( uts ) {
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if ( compat_get_timespec ( & t , uts ) )
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return - EFAULT ;
}
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ret = do_sigtimedwait ( & s , & info , uts ? & t : NULL ) ;
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if ( ret > 0 & & uinfo ) {
if ( copy_siginfo_to_user32 ( uinfo , & info ) )
ret = - EFAULT ;
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}
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return ret ;
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}
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# ifdef __ARCH_WANT_COMPAT_SYS_TIME
/* compat_time_t is a 32 bit "long" and needs to get converted. */
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COMPAT_SYSCALL_DEFINE1 ( time , compat_time_t __user * , tloc )
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{
compat_time_t i ;
struct timeval tv ;
do_gettimeofday ( & tv ) ;
i = tv . tv_sec ;
if ( tloc ) {
if ( put_user ( i , tloc ) )
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return - EFAULT ;
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}
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force_successful_syscall_return ( ) ;
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return i ;
}
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COMPAT_SYSCALL_DEFINE1 ( stime , compat_time_t __user * , tptr )
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{
struct timespec tv ;
int err ;
if ( get_user ( tv . tv_sec , tptr ) )
return - EFAULT ;
tv . tv_nsec = 0 ;
err = security_settime ( & tv , NULL ) ;
if ( err )
return err ;
do_settimeofday ( & tv ) ;
return 0 ;
}
# endif /* __ARCH_WANT_COMPAT_SYS_TIME */
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COMPAT_SYSCALL_DEFINE1 ( adjtimex , struct compat_timex __user * , utp )
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{
struct timex txc ;
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int err , ret ;
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err = compat_get_timex ( & txc , utp ) ;
if ( err )
return err ;
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ret = do_adjtimex ( & txc ) ;
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err = compat_put_timex ( utp , & txc ) ;
if ( err )
return err ;
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return ret ;
}
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# ifdef CONFIG_NUMA
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COMPAT_SYSCALL_DEFINE6 ( move_pages , pid_t , pid , compat_ulong_t , nr_pages ,
compat_uptr_t __user * , pages32 ,
const int __user * , nodes ,
int __user * , status ,
int , flags )
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{
const void __user * __user * pages ;
int i ;
pages = compat_alloc_user_space ( nr_pages * sizeof ( void * ) ) ;
for ( i = 0 ; i < nr_pages ; i + + ) {
compat_uptr_t p ;
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if ( get_user ( p , pages32 + i ) | |
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put_user ( compat_ptr ( p ) , pages + i ) )
return - EFAULT ;
}
return sys_move_pages ( pid , nr_pages , pages , nodes , status , flags ) ;
}
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COMPAT_SYSCALL_DEFINE4 ( migrate_pages , compat_pid_t , pid ,
compat_ulong_t , maxnode ,
const compat_ulong_t __user * , old_nodes ,
const compat_ulong_t __user * , new_nodes )
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{
unsigned long __user * old = NULL ;
unsigned long __user * new = NULL ;
nodemask_t tmp_mask ;
unsigned long nr_bits ;
unsigned long size ;
nr_bits = min_t ( unsigned long , maxnode - 1 , MAX_NUMNODES ) ;
size = ALIGN ( nr_bits , BITS_PER_LONG ) / 8 ;
if ( old_nodes ) {
if ( compat_get_bitmap ( nodes_addr ( tmp_mask ) , old_nodes , nr_bits ) )
return - EFAULT ;
old = compat_alloc_user_space ( new_nodes ? size * 2 : size ) ;
if ( new_nodes )
new = old + size / sizeof ( unsigned long ) ;
if ( copy_to_user ( old , nodes_addr ( tmp_mask ) , size ) )
return - EFAULT ;
}
if ( new_nodes ) {
if ( compat_get_bitmap ( nodes_addr ( tmp_mask ) , new_nodes , nr_bits ) )
return - EFAULT ;
if ( new = = NULL )
new = compat_alloc_user_space ( size ) ;
if ( copy_to_user ( new , nodes_addr ( tmp_mask ) , size ) )
return - EFAULT ;
}
return sys_migrate_pages ( pid , nr_bits + 1 , old , new ) ;
}
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# endif
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COMPAT_SYSCALL_DEFINE2 ( sched_rr_get_interval ,
compat_pid_t , pid ,
struct compat_timespec __user * , interval )
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{
struct timespec t ;
int ret ;
mm_segment_t old_fs = get_fs ( ) ;
set_fs ( KERNEL_DS ) ;
ret = sys_sched_rr_get_interval ( pid , ( struct timespec __user * ) & t ) ;
set_fs ( old_fs ) ;
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if ( compat_put_timespec ( & t , interval ) )
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return - EFAULT ;
return ret ;
}
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/*
* Allocate user - space memory for the duration of a single system call ,
* in order to marshall parameters inside a compat thunk .
*/
void __user * compat_alloc_user_space ( unsigned long len )
{
void __user * ptr ;
/* If len would occupy more than half of the entire compat space... */
if ( unlikely ( len > ( ( ( compat_uptr_t ) ~ 0 ) > > 1 ) ) )
return NULL ;
ptr = arch_compat_alloc_user_space ( len ) ;
if ( unlikely ( ! access_ok ( VERIFY_WRITE , ptr , len ) ) )
return NULL ;
return ptr ;
}
EXPORT_SYMBOL_GPL ( compat_alloc_user_space ) ;
