linux/lib
Mikulas Patocka 3fa6c50731 mm: optimize copy_page_to/from_iter_iovec
copy_page_to_iter_iovec() and copy_page_from_iter_iovec() copy some data
to userspace or from userspace.  These functions have a fast path where
they map a page using kmap_atomic and a slow path where they use kmap.

kmap is slower than kmap_atomic, so the fast path is preferred.

However, on kernels without highmem support, kmap just calls
page_address, so there is no need to avoid kmap.  On kernels without
highmem support, the fast path just increases code size (and cache
footprint) and it doesn't improve copy performance in any way.

This patch enables the fast path only if CONFIG_HIGHMEM is defined.

Code size reduced by this patch:
  x86 (without highmem)	  928
  x86-64		  960
  sparc64		  848
  alpha			 1136
  pa-risc		 1200

[akpm@linux-foundation.org: use IS_ENABLED(), per Andi]
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1607221711410.4818@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
..
842 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2016-03-17 21:38:27 -07:00
fonts fonts: Add 6x10 font 2014-10-09 11:35:48 +03:00
lz4 lib: lz4: cleanup unaligned access efficiency detection 2016-04-13 09:22:49 -07:00
lzo lzo: check for length overrun in variable length encoding. 2014-09-28 11:08:01 +02:00
mpi lib/mpi: Do not do sg_virt 2016-07-01 23:45:18 +08:00
raid6 powerpc: Create disable_kernel_{fp,altivec,vsx,spe}() 2015-12-01 13:52:25 +11:00
reed_solomon
xz lib/xz: enable all filters by default in Kconfig 2014-06-04 16:54:18 -07:00
zlib_deflate zlib_deflate/deftree: remove bi_reverse() 2015-09-10 13:29:01 -07:00
zlib_inflate zlib: clean up some dead code 2014-08-06 18:01:24 -07:00
.gitignore
argv_split.c
asn1_decoder.c Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-05-17 09:33:39 -07:00
assoc_array.c assoc_array: don't call compare_object() on a node 2016-04-06 14:06:48 +01:00
atomic64_test.c locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() 2016-06-16 10:48:32 +02:00
atomic64.c locking/atomic: Implement atomic{,64,_long}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}() 2016-06-16 10:48:32 +02:00
audit.c syscalls: implement execveat() system call 2014-12-13 12:42:51 -08:00
bcd.c
bch.c
bitmap.c x86/uaccess: Move thread_info::addr_limit to thread_struct 2016-07-15 10:26:30 +02:00
bitrev.c ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction 2014-12-22 16:43:06 +00:00
bsearch.c
btree.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
bug.c lib/bug.c: use common WARN helper 2016-03-17 15:09:34 -07:00
build_OID_registry
bust_spinlocks.c
chacha20.c random: replace non-blocking pool with a Chacha20-based CRNG 2016-07-03 00:57:23 -04:00
check_signature.c
checksum.c ipv4: Update parameters for csum_tcpudp_magic to their original types 2016-03-13 23:55:13 -04:00
clz_ctz.c lib/clz_ctz.c: add prototype declarations in lib/clz_ctz.c 2014-04-03 16:21:12 -07:00
clz_tab.c
cmdline.c lib: Add a generic cmdline parse function parse_option_str 2014-10-03 18:40:58 +01:00
compat_audit.c audit: Add generic compat syscall support 2014-03-20 10:11:35 -04:00
cordic.c
cpu_rmap.c sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask() 2015-05-27 15:22:15 +02:00
cpu-notifier-error-inject.c
cpumask.c cpumask: Export cpumask_any_but() 2016-02-29 09:35:20 +01:00
crc7.c lib/crc7: Shift crc7() output left 1 bit 2014-05-16 14:26:52 -04:00
crc8.c
crc16.c
crc32.c lib: crc32: Add some additional __pure annotations 2014-06-25 16:04:00 -07:00
crc32defs.h
crc-ccitt.c
crc-itu-t.c lib: crc-itu-t.[ch] fix 0x0x prefix in integer constants 2015-05-26 15:26:43 +02:00
crc-t10dif.c lib: introduce crc_t10dif_update() 2015-05-30 22:42:24 -07:00
ctype.c
debug_info.c kbuild: include core debug info when DEBUG_INFO_REDUCED 2015-06-11 15:08:32 +02:00
debug_locks.c
debugobjects.c debugobjects: insulate non-fixup logic related to static obj from fixup callbacks 2016-05-19 19:12:14 -07:00
dec_and_lock.c
decompress_bunzip2.c lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
decompress_inflate.c lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
decompress_unlz4.c lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
decompress_unlzma.c lib/decompress_unlzma: Do a NULL check for pointer 2015-09-10 13:29:01 -07:00
decompress_unlzo.c lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
decompress_unxz.c lib/decompressors: use real out buf size for gunzip with kernel 2015-09-10 13:29:01 -07:00
decompress.c lib/decompress: set the compressor name to NULL on error 2015-07-17 16:39:54 -07:00
devres.c devres: use to_pci_dev() 2016-02-07 23:17:59 -08:00
digsig.c lib/digsig: digsig_verify_rsa(): return -EINVAL if modulo length is zero 2016-05-31 16:42:00 +08:00
div64.c __div64_32(): make it overridable at compile time 2015-11-16 14:42:12 -05:00
dma-debug.c dma-debug: track bucket lock state for static checkers 2016-07-26 16:19:19 -07:00
dma-noop.c dma: Provide simple noop dma ops 2016-03-02 17:01:55 +02:00
dump_stack.c dump_stack: avoid potential deadlocks 2016-02-05 18:10:40 -08:00
dynamic_debug.c convert a bunch of open-coded instances of memdup_user_nul() 2016-01-04 10:26:58 -05:00
dynamic_queue_limits.c lib/dynamic_queue_limits.c: simplify includes 2015-02-12 18:54:15 -08:00
earlycpio.c
extable.c extable: add support for relative extables to search and sort routines 2016-02-24 14:57:26 +00:00
fault-inject.c fault-inject: fix inverted interval/probability values in printk 2015-10-23 17:55:10 +09:00
fdt_empty_tree.c lib: add fdt_empty_tree.c 2014-04-30 19:49:37 +01:00
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
fdt.c
find_bit.c lib: rename lib/find_next_bit.c to lib/find_bit.c 2015-04-17 09:03:54 -04:00
flex_array.c reciprocal_divide: update/correction of the algorithm 2014-01-21 23:17:20 -08:00
flex_proportions.c lib+mm: fix few spelling mistakes 2016-02-15 11:18:23 +01:00
gcd.c lib/GCD.c: use binary GCD algorithm instead of Euclidean 2016-05-20 17:58:30 -07:00
gen_crc32table.c lib: crc32: constify crc32 lookup table 2015-02-13 21:21:35 -08:00
genalloc.c CPM/QE: use genalloc to manage CPM/QE muram 2015-12-22 17:10:18 -06:00
glob.c lib/glob.c: add CONFIG_GLOB_SELFTEST 2014-08-06 18:01:25 -07:00
halfmd4.c lib/halfmd4.c: use rol32 inline function in the ROUND macro 2015-11-06 17:50:42 -08:00
hexdump.c lib/hexdump.c: truncate output in case of overflow 2015-11-06 17:50:42 -08:00
hweight.c x86/hweight: Get rid of the special calling convention 2016-06-08 15:01:02 +02:00
idr.c mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd 2015-11-06 17:50:42 -08:00
inflate.c
int_sqrt.c
interval_tree_test.c lib: Export interval_tree 2014-05-05 09:09:14 +02:00
interval_tree.c lib/interval_tree.c: simplify includes 2015-02-12 18:54:15 -08:00
iomap_copy.c lib/iomap_copy.c: add __ioread32_copy() 2016-01-20 17:09:18 -08:00
iomap.c Kconfig: rename HAS_IOPORT to HAS_IOPORT_MAP 2014-04-07 16:36:11 -07:00
iommu-common.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2015-11-05 16:34:48 -08:00
iommu-helper.c
ioremap.c x86, mm: support huge KVA mappings on x86 2015-04-14 16:49:04 -07:00
iov_iter.c mm: optimize copy_page_to/from_iter_iovec 2016-07-28 16:07:41 -07:00
irq_poll.c irq_poll: Fix irq_poll_sched() 2016-01-19 15:26:55 -05:00
irq_regs.c
is_single_threaded.c lib/is_single_threaded.c: change current_is_single_threaded() to use for_each_thread() 2015-11-06 17:50:42 -08:00
jedec_ddr_data.c
kasprintf.c lib/kasprintf.c: add sanity check to kvasprintf 2016-01-16 11:17:27 -08:00
Kconfig raxix-tree: introduce CONFIG_RADIX_TREE_MULTIORDER 2016-05-20 17:58:30 -07:00
Kconfig.debug mm/page_owner: use stackdepot to store stacktrace 2016-07-26 16:19:19 -07:00
Kconfig.kasan mm, kasan: stackdepot implementation. Enable stackdepot for SLAB 2016-03-25 16:37:42 -07:00
Kconfig.kgdb kgdb: depends on VT 2016-05-23 17:04:14 -07:00
Kconfig.kmemcheck
Kconfig.ubsan ubsan: fix tree-wide -Wmaybe-uninitialized false positives 2016-03-22 15:36:02 -07:00
kfifo.c kfifo: use BUG_ON 2014-08-08 15:57:25 -07:00
klist.c klist: fix starting point removed bug in klist iterators 2016-02-07 22:18:47 -08:00
kobject_uevent.c lib/kobject_uevent.c: remove redundant include 2015-02-12 18:54:15 -08:00
kobject.c kobject: export kset_find_obj() for module use 2016-02-09 17:36:34 -08:00
kstrtox.c lib: add "on"/"off" support to kstrtobool 2016-03-17 15:09:34 -07:00
kstrtox.h
lcm.c block: fix blk_stack_limits() regression due to lcm() change 2015-03-31 09:45:50 -06:00
libcrc32c.c Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2016-01-22 11:58:43 -08:00
list_debug.c list: kill list_force_poison() 2016-03-09 15:43:42 -08:00
list_sort.c lib/list_sort: use late_initcall to hook in self tests 2015-06-16 14:12:35 -04:00
llist.c lib/llist.c: fix data race in llist_del_first 2015-11-06 17:50:42 -08:00
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c locking/lockdep: Revert qrwlock recusive stuff 2014-10-03 06:09:30 +02:00
lockref.c locking/lockref: Remove homebrew cmpxchg64_relaxed() macro definition 2015-08-12 11:59:04 +02:00
lru_cache.c lru_cache: Converted lc_seq_printf_status to return void 2015-11-25 09:22:02 -07:00
Makefile A number of improvements for the /dev/random driver; the most 2016-07-27 15:11:55 -07:00
md5.c lib/md5.c: simplify include 2015-02-12 18:54:15 -08:00
memory-notifier-error-inject.c
memweight.c
net_utils.c mac_pton: Use bool not int return 2014-06-25 17:45:43 -07:00
netdev-notifier-error-inject.c net: Add support for CHANGEUPPER notifier error injection 2015-12-03 11:49:23 -05:00
nlattr.c libnl: fix help of _64bit functions 2016-04-23 20:13:24 -04:00
nmi_backtrace.c printk/nmi: generic solution for safe printk in NMI 2016-05-20 17:58:30 -07:00
nodemask.c include/linux/nodemask.h: create next_node_in() helper 2016-05-19 19:12:14 -07:00
notifier-error-inject.c
notifier-error-inject.h
of-reconfig-notifier-error-inject.c
oid_registry.c
once.c once: make helper generic for calling functions once 2015-10-08 05:26:36 -07:00
parser.c lib/parser.c: put EXPORT_SYMBOLs in the conventional place 2014-01-23 16:36:55 -08:00
pci_iomap.c libnvdimm for 4.3: 2015-09-08 14:35:59 -07:00
percpu_counter.c percpu_counter: update debugobjects fixup callbacks return type 2016-05-19 19:12:14 -07:00
percpu_ida.c mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM 2015-11-06 17:50:42 -08:00
percpu_test.c
percpu-refcount.c lib+mm: fix few spelling mistakes 2016-02-15 11:18:23 +01:00
plist.c lib/plist.c: remove redundant include 2015-02-12 18:54:16 -08:00
pm-notifier-error-inject.c
radix-tree.c radix-tree: implement radix_tree_maybe_preload_order() 2016-07-26 16:19:19 -07:00
random32.c timers: Remove set_timer_slack() leftovers 2016-07-07 10:35:09 +02:00
ratelimit.c ratelimit: fix bug in time interval by resetting right begin time 2016-01-21 17:20:51 -08:00
rational.c
rbtree_test.c rbtree/test: test rbtree_postorder_for_each_entry_safe() 2014-01-23 16:37:03 -08:00
rbtree.c Introduce rb_replace_node_rcu() 2016-07-06 10:51:14 +01:00
reciprocal_div.c reciprocal_divide: update/correction of the algorithm 2014-01-21 23:17:20 -08:00
rhashtable.c rhashtable: accept GFP flags in rhashtable_walk_init 2016-04-05 10:56:32 +02:00
scatterlist.c scatterlist: fix a typo in comment block of sg_miter_stop() 2016-02-08 10:15:17 -08:00
seq_buf.c tracing: Use seq_buf_used() in seq_buf_to_user() instead of len 2015-12-23 14:27:20 -05:00
sg_pool.c lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c 2016-04-15 16:53:14 -04:00
sg_split.c lib: scatterlist: add sg splitting function 2015-08-24 14:28:01 -06:00
sha1.c lib: EXPORT_SYMBOL sha_init 2015-03-23 22:12:08 -04:00
show_mem.c lib/show_mem.c: correct reserved memory calculation 2015-09-08 15:35:28 -07:00
smp_processor_id.c percpu: add preemption checks to __this_cpu ops 2014-04-07 16:36:14 -07:00
sort.c lib/sort: Add 64 bit swap function 2015-06-25 17:00:40 -07:00
stackdepot.c lib/stackdepot: avoid to return 0 handle 2016-05-05 17:38:53 -07:00
stmp_device.c lib/stmp_device.c: replace module.h include 2015-02-12 18:54:16 -08:00
string_helpers.c string_helpers: add kstrdup_quotable_file 2016-04-21 10:47:26 +10:00
string.c lib: move strtobool() to kstrtobool() 2016-03-17 15:09:34 -07:00
strncpy_from_user.c x86/kasan: instrument user memory access API 2016-05-20 17:58:30 -07:00
strnlen_user.c Use the new batched user accesses in generic user string handling 2015-12-17 10:05:19 -08:00
swiotlb.c Merge branch 'for-4.2/sg' of git://git.kernel.dk/linux-block 2015-06-25 15:22:36 -07:00
syscall.c lib/syscall.c: unexport task_current_syscall() 2014-04-03 16:21:06 -07:00
test_bitmap.c test_bitmap: unit tests for lib/bitmap.c 2016-02-19 22:54:09 -05:00
test_bpf.c bpf: prepare bpf_int_jit_compile/bpf_prog_select_runtime apis 2016-05-16 13:49:32 -04:00
test_firmware.c test: firmware_class: add asynchronous request trigger 2016-01-07 13:44:22 -07:00
test_hash.c <linux/hash.h>: Add support for architecture-specific functions 2016-05-28 15:48:31 -04:00
test_hexdump.c test_hexdump: print statistics at the end 2016-01-20 17:09:18 -08:00
test_kasan.c kasan/tests: add tests for user memory access functions 2016-05-20 17:58:30 -07:00
test_module.c test: add minimal module for verification testing 2014-01-23 16:36:57 -08:00
test_printf.c mm, printk: introduce new format string for flags 2016-03-15 16:55:16 -07:00
test_rhashtable.c rhashtable: accept GFP flags in rhashtable_walk_init 2016-04-05 10:56:32 +02:00
test_static_key_base.c locking/static_keys: Provide a selftest 2015-08-03 11:51:12 +02:00
test_static_keys.c locking/static_keys: Avoid nested functions 2016-02-09 10:27:29 +01:00
test_user_copy.c test: check copy_to/from_user boundary validation 2014-01-23 16:36:57 -08:00
test_uuid.c lib/uuid: add a test module 2016-05-30 15:26:57 -07:00
test-kstrtox.c kstrto*: accept "-0" for signed conversion 2015-09-10 13:29:01 -07:00
test-string_helpers.c lib/test-string_helpers.c: fix and improve string_get_size() tests 2016-02-03 08:28:43 -08:00
textsearch.c lib/textsearch.c: remove textsearch_put reference from comments 2014-10-14 02:18:14 +02:00
timerqueue.c timerqueue: Let timerqueue_add/del return information 2015-04-22 17:06:49 +02:00
ts_bm.c
ts_fsm.c
ts_kmp.c
ubsan.c UBSAN: run-time undefined behavior sanity checker 2016-01-20 17:09:18 -08:00
ubsan.h UBSAN: run-time undefined behavior sanity checker 2016-01-20 17:09:18 -08:00
ucs2_string.c lib/ucs2_string: Correct ucs2 -> utf8 conversion 2016-02-16 12:49:05 +00:00
usercopy.c
uuid.c lib/uuid.c: use correct offset in uuid parser 2016-05-30 15:26:57 -07:00
vsprintf.c lib/uuid.c: introduce a few more generic helpers 2016-05-20 17:58:30 -07:00