52b37ae8aa
768 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
David Hildenbrand
|
42b2af2c9b |
mm/userfaultfd: propagate uffd-wp bit when PTE-mapping the huge zeropage
Currently, we'd lose the userfaultfd-wp marker when PTE-mapping a huge
zeropage, resulting in the next write faults in the PMD range not
triggering uffd-wp events.
Various actions (partial MADV_DONTNEED, partial mremap, partial munmap,
partial mprotect) could trigger this. However, most importantly,
un-protecting a single sub-page from the userfaultfd-wp handler when
processing a uffd-wp event will PTE-map the shared huge zeropage and lose
the uffd-wp bit for the remainder of the PMD.
Let's properly propagate the uffd-wp bit to the PMDs.
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <inttypes.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <poll.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <linux/userfaultfd.h>
static size_t pagesize;
static int uffd;
static volatile bool uffd_triggered;
#define barrier() __asm__ __volatile__("": : :"memory")
static void uffd_wp_range(char *start, size_t size, bool wp)
{
struct uffdio_writeprotect uffd_writeprotect;
uffd_writeprotect.range.start = (unsigned long) start;
uffd_writeprotect.range.len = size;
if (wp) {
uffd_writeprotect.mode = UFFDIO_WRITEPROTECT_MODE_WP;
} else {
uffd_writeprotect.mode = 0;
}
if (ioctl(uffd, UFFDIO_WRITEPROTECT, &uffd_writeprotect)) {
fprintf(stderr, "UFFDIO_WRITEPROTECT failed: %d\n", errno);
exit(1);
}
}
static void *uffd_thread_fn(void *arg)
{
static struct uffd_msg msg;
ssize_t nread;
while (1) {
struct pollfd pollfd;
int nready;
pollfd.fd = uffd;
pollfd.events = POLLIN;
nready = poll(&pollfd, 1, -1);
if (nready == -1) {
fprintf(stderr, "poll() failed: %d\n", errno);
exit(1);
}
nread = read(uffd, &msg, sizeof(msg));
if (nread <= 0)
continue;
if (msg.event != UFFD_EVENT_PAGEFAULT ||
!(msg.arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP)) {
printf("FAIL: wrong uffd-wp event fired\n");
exit(1);
}
/* un-protect the single page. */
uffd_triggered = true;
uffd_wp_range((char *)(uintptr_t)msg.arg.pagefault.address,
pagesize, false);
}
return arg;
}
static int setup_uffd(char *map, size_t size)
{
struct uffdio_api uffdio_api;
struct uffdio_register uffdio_register;
pthread_t thread;
uffd = syscall(__NR_userfaultfd,
O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY);
if (uffd < 0) {
fprintf(stderr, "syscall() failed: %d\n", errno);
return -errno;
}
uffdio_api.api = UFFD_API;
uffdio_api.features = UFFD_FEATURE_PAGEFAULT_FLAG_WP;
if (ioctl(uffd, UFFDIO_API, &uffdio_api) < 0) {
fprintf(stderr, "UFFDIO_API failed: %d\n", errno);
return -errno;
}
if (!(uffdio_api.features & UFFD_FEATURE_PAGEFAULT_FLAG_WP)) {
fprintf(stderr, "UFFD_FEATURE_WRITEPROTECT missing\n");
return -ENOSYS;
}
uffdio_register.range.start = (unsigned long) map;
uffdio_register.range.len = size;
uffdio_register.mode = UFFDIO_REGISTER_MODE_WP;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) < 0) {
fprintf(stderr, "UFFDIO_REGISTER failed: %d\n", errno);
return -errno;
}
pthread_create(&thread, NULL, uffd_thread_fn, NULL);
return 0;
}
int main(void)
{
const size_t size = 4 * 1024 * 1024ull;
char *map, *cur;
pagesize = getpagesize();
map = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "mmap() failed\n");
return -errno;
}
if (madvise(map, size, MADV_HUGEPAGE)) {
fprintf(stderr, "MADV_HUGEPAGE failed\n");
return -errno;
}
if (setup_uffd(map, size))
return 1;
/* Read the whole range, populating zeropages. */
madvise(map, size, MADV_POPULATE_READ);
/* Write-protect the whole range. */
uffd_wp_range(map, size, true);
/* Make sure uffd-wp triggers on each page. */
for (cur = map; cur < map + size; cur += pagesize) {
uffd_triggered = false;
barrier();
/* Trigger a write fault. */
*cur = 1;
barrier();
if (!uffd_triggered) {
printf("FAIL: uffd-wp did not trigger\n");
return 1;
}
}
printf("PASS: uffd-wp triggered\n");
return 0;
}
Link: https://lkml.kernel.org/r/20230302175423.589164-1-david@redhat.com
Fixes:
|
||
Linus Torvalds
|
3822a7c409 |
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter". These filters provide users
with finer-grained control over DAMOS's actions. SeongJae has also done
some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series "mm:
support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with his
series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings. The previous BPF-based approach had
shortcomings. See "mm: In-kernel support for memory-deny-write-execute
(MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a per-node
basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage during
compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in ths
series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's series
"mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
"fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest of
the kernel in the series "Simplify the external interface for GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the series
"mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
|
||
Peter Xu
|
96a9c287e2 |
mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
Nick Bowler reported another sparc64 breakage after the young/dirty
persistent work for page migration (per "Link:" below). That's after a
similar report [2].
It turns out page migration was overlooked, and it wasn't failing before
because page migration was not enabled in the initial report test
environment.
David proposed another way [2] to fix this from sparc64 side, but that
patch didn't land somehow. Neither did I check whether there's any other
arch that has similar issues.
Let's fix it for now as simple as moving the write bit handling to be
after dirty, like what we did before.
Note: this is based on mm-unstable, because the breakage was since 6.1 and
we're at a very late stage of 6.2 (-rc8), so I assume for this specific
case we should target this at 6.3.
[1] https://lore.kernel.org/all/20221021160603.GA23307@u164.east.ru/
[2] https://lore.kernel.org/all/20221212130213.136267-1-david@redhat.com/
Link: https://lkml.kernel.org/r/20230216153059.256739-1-peterx@redhat.com
Fixes:
|
||
Jason Gunthorpe
|
d64e2dbc33 |
mm/gup: simplify the external interface functions and consolidate invariants
The GUP family of functions have a complex, but fairly well defined, set of invariants for their arguments. Currently these are sprinkled about, sometimes in duplicate through many functions. Internally we don't follow all the invariants that the external interface has to follow, so place these checks directly at the exported interface. This ensures the internal functions never reach a violated invariant. Remove the duplicated invariant checks. The end result is to make these functions fully internal: __get_user_pages_locked() internal_get_user_pages_fast() __gup_longterm_locked() And all the other functions call directly into one of these. Link: https://lkml.kernel.org/r/5-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
David Stevens
|
2cf1338454 |
mm: fix khugepaged with shmem_enabled=advise
Pass vm_flags as a parameter to shmem_is_huge, rather than reading the flags from the vm_area_struct in question. This allows the updated flags from hugepage_madvise to be passed to the check, which is necessary because madvise does not update the vm_area_struct's flags until after hugepage_madvise returns. This fixes an issue when shmem_enabled=madvise, where MADV_HUGEPAGE on shmem was not able to register the mm_struct with khugepaged. Prior to |
||
Matthew Wilcox (Oracle)
|
f158ed6195 |
mm: convert deferred_split_huge_page() to deferred_split_folio()
Now that both callers use a folio, pass the folio in and save a call to compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-28-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
f8baa6be03 |
mm/huge_memory: convert get_deferred_split_queue() to take a folio
Removes a few calls to compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-27-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
8991de90e9 |
mm/huge_memory: remove page_deferred_list()
Use folio->_deferred_list directly. Link: https://lkml.kernel.org/r/20230111142915.1001531-26-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
4375a553f4 |
mm: move page->deferred_list to folio->_deferred_list
Remove the entire block of definitions for the second tail page, and add the deferred list to the struct folio. This actually moves _deferred_list to a different offset in struct folio because I don't see a need to include the padding. This lets us use list_for_each_entry_safe() in deferred_split_scan() and avoid a number of calls to compound_head(). Link: https://lkml.kernel.org/r/20230111142915.1001531-25-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
f04029f34e |
mm: convert is_transparent_hugepage() to use a folio
Replace a use of page->compound_dtor with its folio equivalent. Link: https://lkml.kernel.org/r/20230111142915.1001531-20-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
94688e8eb4 |
mm: remove folio_pincount_ptr() and head_compound_pincount()
We can use folio->_pincount directly, since all users are guarded by tests of compound/large. Link: https://lkml.kernel.org/r/20230111142915.1001531-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Alistair Popple
|
7d4a8be0c4 |
mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export
mmu_notifier_range_update_to_read_only() was originally introduced in
commit
|
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Kefeng Wang
|
630e7c5ee3 |
mm: huge_memory: convert split_huge_pages_all() to use a folio
Straightforwardly convert split_huge_pages_all() to use a folio. Link: https://lkml.kernel.org/r/20221229122503.149083-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Yin Fengwei
|
81e506bec9 |
mm/thp: check and bail out if page in deferred queue already
Kernel build regression with LLVM was reported here: https://lore.kernel.org/all/Y1GCYXGtEVZbcv%2F5@dev-arch.thelio-3990X/ with commit |
||
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Kefeng Wang
|
6a6fe9ebd5 |
mm: swap: convert mark_page_lazyfree() to folio_mark_lazyfree()
mark_page_lazyfree() and the callers are converted to use folio, this rename and make it to take in a folio argument instead of calling page_folio(). Link: https://lkml.kernel.org/r/20221209020618.190306-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
fc986a38b6 |
mm: huge_memory: convert madvise_free_huge_pmd to use a folio
Using folios instead of pages removes several calls to compound_head(), Link: https://lkml.kernel.org/r/20221207023431.151008-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
f1eb1bacfb |
mm/uffd: always wr-protect pte in pte|pmd_mkuffd_wp()
This patch is a cleanup to always wr-protect pte/pmd in mkuffd_wp paths.
The reasons I still think this patch is worthwhile, are:
(1) It is a cleanup already; diffstat tells.
(2) It just feels natural after I thought about this, if the pte is uffd
protected, let's remove the write bit no matter what it was.
(2) Since x86 is the only arch that supports uffd-wp, it also redefines
pte|pmd_mkuffd_wp() in that it should always contain removals of
write bits. It means any future arch that want to implement uffd-wp
should naturally follow this rule too. It's good to make it a
default, even if with vm_page_prot changes on VM_UFFD_WP.
(3) It covers more than vm_page_prot. So no chance of any potential
future "accident" (like pte_mkdirty() sparc64 or loongarch, even
though it just got its pte_mkdirty fixed <1 month ago). It'll be
fairly clear when reading the code too that we don't worry anything
before a pte_mkuffd_wp() on uncertainty of the write bit.
We may call pte_wrprotect() one more time in some paths (e.g. thp split),
but that should be fully local bitop instruction so the overhead should be
negligible.
Although this patch should logically also fix all the known issues on
uffd-wp too recently on page migration (not for numa hint recovery - that
may need another explcit pte_wrprotect), but this is not the plan for that
fix. So no fixes, and stable doesn't need this.
Link: https://lkml.kernel.org/r/20221214201533.1774616-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ives van Hoorne <ives@codesandbox.io>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Linus Torvalds
|
8fa590bf34 |
ARM64:
* Enable the per-vcpu dirty-ring tracking mechanism, together with an option to keep the good old dirty log around for pages that are dirtied by something other than a vcpu. * Switch to the relaxed parallel fault handling, using RCU to delay page table reclaim and giving better performance under load. * Relax the MTE ABI, allowing a VMM to use the MAP_SHARED mapping option, which multi-process VMMs such as crosvm rely on (see merge commit |
||
|
Linus Torvalds
|
e2ca6ba6ba |
MM patches for 6.2-rc1.
- More userfaultfs work from Peter Xu. - Several convert-to-folios series from Sidhartha Kumar and Huang Ying. - Some filemap cleanups from Vishal Moola. - David Hildenbrand added the ability to selftest anon memory COW handling. - Some cpuset simplifications from Liu Shixin. - Addition of vmalloc tracing support by Uladzislau Rezki. - Some pagecache folioifications and simplifications from Matthew Wilcox. - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use it. - Miguel Ojeda contributed some cleanups for our use of the __no_sanitize_thread__ gcc keyword. This series shold have been in the non-MM tree, my bad. - Naoya Horiguchi improved the interaction between memory poisoning and memory section removal for huge pages. - DAMON cleanups and tuneups from SeongJae Park - Tony Luck fixed the handling of COW faults against poisoned pages. - Peter Xu utilized the PTE marker code for handling swapin errors. - Hugh Dickins reworked compound page mapcount handling, simplifying it and making it more efficient. - Removal of the autonuma savedwrite infrastructure from Nadav Amit and David Hildenbrand. - zram support for multiple compression streams from Sergey Senozhatsky. - David Hildenbrand reworked the GUP code's R/O long-term pinning so that drivers no longer need to use the FOLL_FORCE workaround which didn't work very well anyway. - Mel Gorman altered the page allocator so that local IRQs can remnain enabled during per-cpu page allocations. - Vishal Moola removed the try_to_release_page() wrapper. - Stefan Roesch added some per-BDI sysfs tunables which are used to prevent network block devices from dirtying excessive amounts of pagecache. - David Hildenbrand did some cleanup and repair work on KSM COW breaking. - Nhat Pham and Johannes Weiner have implemented writeback in zswap's zsmalloc backend. - Brian Foster has fixed a longstanding corner-case oddity in file[map]_write_and_wait_range(). - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang Chen. - Shiyang Ruan has done some work on fsdax, to make its reflink mode work better under xfstests. Better, but still not perfect. - Christoph Hellwig has removed the .writepage() method from several filesystems. They only need .writepages(). - Yosry Ahmed wrote a series which fixes the memcg reclaim target beancounting. - David Hildenbrand has fixed some of our MM selftests for 32-bit machines. - Many singleton patches, as usual. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY5j6ZwAKCRDdBJ7gKXxA jkDYAP9qNeVqp9iuHjZNTqzMXkfmJPsw2kmy2P+VdzYVuQRcJgEAgoV9d7oMq4ml CodAgiA51qwzId3GRytIo/tfWZSezgA= =d19R -----END PGP SIGNATURE----- Merge tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - More userfaultfs work from Peter Xu - Several convert-to-folios series from Sidhartha Kumar and Huang Ying - Some filemap cleanups from Vishal Moola - David Hildenbrand added the ability to selftest anon memory COW handling - Some cpuset simplifications from Liu Shixin - Addition of vmalloc tracing support by Uladzislau Rezki - Some pagecache folioifications and simplifications from Matthew Wilcox - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use it - Miguel Ojeda contributed some cleanups for our use of the __no_sanitize_thread__ gcc keyword. This series should have been in the non-MM tree, my bad - Naoya Horiguchi improved the interaction between memory poisoning and memory section removal for huge pages - DAMON cleanups and tuneups from SeongJae Park - Tony Luck fixed the handling of COW faults against poisoned pages - Peter Xu utilized the PTE marker code for handling swapin errors - Hugh Dickins reworked compound page mapcount handling, simplifying it and making it more efficient - Removal of the autonuma savedwrite infrastructure from Nadav Amit and David Hildenbrand - zram support for multiple compression streams from Sergey Senozhatsky - David Hildenbrand reworked the GUP code's R/O long-term pinning so that drivers no longer need to use the FOLL_FORCE workaround which didn't work very well anyway - Mel Gorman altered the page allocator so that local IRQs can remnain enabled during per-cpu page allocations - Vishal Moola removed the try_to_release_page() wrapper - Stefan Roesch added some per-BDI sysfs tunables which are used to prevent network block devices from dirtying excessive amounts of pagecache - David Hildenbrand did some cleanup and repair work on KSM COW breaking - Nhat Pham and Johannes Weiner have implemented writeback in zswap's zsmalloc backend - Brian Foster has fixed a longstanding corner-case oddity in file[map]_write_and_wait_range() - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang Chen - Shiyang Ruan has done some work on fsdax, to make its reflink mode work better under xfstests. Better, but still not perfect - Christoph Hellwig has removed the .writepage() method from several filesystems. They only need .writepages() - Yosry Ahmed wrote a series which fixes the memcg reclaim target beancounting - David Hildenbrand has fixed some of our MM selftests for 32-bit machines - Many singleton patches, as usual * tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (313 commits) mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio mm: mmu_gather: allow more than one batch of delayed rmaps mm: fix typo in struct pglist_data code comment kmsan: fix memcpy tests mm: add cond_resched() in swapin_walk_pmd_entry() mm: do not show fs mm pc for VM_LOCKONFAULT pages selftests/vm: ksm_functional_tests: fixes for 32bit selftests/vm: cow: fix compile warning on 32bit selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions mm/gup_test: fix PIN_LONGTERM_TEST_READ with highmem mm,thp,rmap: fix races between updates of subpages_mapcount mm: memcg: fix swapcached stat accounting mm: add nodes= arg to memory.reclaim mm: disable top-tier fallback to reclaim on proactive reclaim selftests: cgroup: make sure reclaim target memcg is unprotected selftests: cgroup: refactor proactive reclaim code to reclaim_until() mm: memcg: fix stale protection of reclaim target memcg mm/mmap: properly unaccount memory on mas_preallocate() failure omfs: remove ->writepage jfs: remove ->writepage ... |
||
|
Linus Torvalds
|
ce8a79d560 |
for-6.2/block-2022-12-08
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Merge tag 'for-6.2/block-2022-12-08' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull requests via Christoph:
- Support some passthrough commands without CAP_SYS_ADMIN (Kanchan
Joshi)
- Refactor PCIe probing and reset (Christoph Hellwig)
- Various fabrics authentication fixes and improvements (Sagi
Grimberg)
- Avoid fallback to sequential scan due to transient issues (Uday
Shankar)
- Implement support for the DEAC bit in Write Zeroes (Christoph
Hellwig)
- Allow overriding the IEEE OUI and firmware revision in configfs
for nvmet (Aleksandr Miloserdov)
- Force reconnect when number of queue changes in nvmet (Daniel
Wagner)
- Minor fixes and improvements (Uros Bizjak, Joel Granados, Sagi
Grimberg, Christoph Hellwig, Christophe JAILLET)
- Fix and cleanup nvme-fc req allocation (Chaitanya Kulkarni)
- Use the common tagset helpers in nvme-pci driver (Christoph
Hellwig)
- Cleanup the nvme-pci removal path (Christoph Hellwig)
- Use kstrtobool() instead of strtobool (Christophe JAILLET)
- Allow unprivileged passthrough of Identify Controller (Joel
Granados)
- Support io stats on the mpath device (Sagi Grimberg)
- Minor nvmet cleanup (Sagi Grimberg)
- MD pull requests via Song:
- Code cleanups (Christoph)
- Various fixes
- Floppy pull request from Denis:
- Fix a memory leak in the init error path (Yuan)
- Series fixing some batch wakeup issues with sbitmap (Gabriel)
- Removal of the pktcdvd driver that was deprecated more than 5 years
ago, and subsequent removal of the devnode callback in struct
block_device_operations as no users are now left (Greg)
- Fix for partition read on an exclusively opened bdev (Jan)
- Series of elevator API cleanups (Jinlong, Christoph)
- Series of fixes and cleanups for blk-iocost (Kemeng)
- Series of fixes and cleanups for blk-throttle (Kemeng)
- Series adding concurrent support for sync queues in BFQ (Yu)
- Series bringing drbd a bit closer to the out-of-tree maintained
version (Christian, Joel, Lars, Philipp)
- Misc drbd fixes (Wang)
- blk-wbt fixes and tweaks for enable/disable (Yu)
- Fixes for mq-deadline for zoned devices (Damien)
- Add support for read-only and offline zones for null_blk
(Shin'ichiro)
- Series fixing the delayed holder tracking, as used by DM (Yu,
Christoph)
- Series enabling bio alloc caching for IRQ based IO (Pavel)
- Series enabling userspace peer-to-peer DMA (Logan)
- BFQ waker fixes (Khazhismel)
- Series fixing elevator refcount issues (Christoph, Jinlong)
- Series cleaning up references around queue destruction (Christoph)
- Series doing quiesce by tagset, enabling cleanups in drivers
(Christoph, Chao)
- Series untangling the queue kobject and queue references (Christoph)
- Misc fixes and cleanups (Bart, David, Dawei, Jinlong, Kemeng, Ye,
Yang, Waiman, Shin'ichiro, Randy, Pankaj, Christoph)
* tag 'for-6.2/block-2022-12-08' of git://git.kernel.dk/linux: (247 commits)
blktrace: Fix output non-blktrace event when blk_classic option enabled
block: sed-opal: Don't include <linux/kernel.h>
sed-opal: allow using IOC_OPAL_SAVE for locking too
blk-cgroup: Fix typo in comment
block: remove bio_set_op_attrs
nvmet: don't open-code NVME_NS_ATTR_RO enumeration
nvme-pci: use the tagset alloc/free helpers
nvme: add the Apple shared tag workaround to nvme_alloc_io_tag_set
nvme: only set reserved_tags in nvme_alloc_io_tag_set for fabrics controllers
nvme: consolidate setting the tagset flags
nvme: pass nr_maps explicitly to nvme_alloc_io_tag_set
block: bio_copy_data_iter
nvme-pci: split out a nvme_pci_ctrl_is_dead helper
nvme-pci: return early on ctrl state mismatch in nvme_reset_work
nvme-pci: rename nvme_disable_io_queues
nvme-pci: cleanup nvme_suspend_queue
nvme-pci: remove nvme_pci_disable
nvme-pci: remove nvme_disable_admin_queue
nvme: merge nvme_shutdown_ctrl into nvme_disable_ctrl
nvme: use nvme_wait_ready in nvme_shutdown_ctrl
...
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||
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David Hildenbrand
|
cb8d863313 |
mm: remove VM_FAULT_WRITE
All users -- GUP and KSM -- are gone, let's just remove it. Link: https://lkml.kernel.org/r/20221021101141.84170-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Peter Xu
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e833bc5034 |
mm/thp: re-apply mkdirty for small pages after split
We used to have |
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David Hildenbrand
|
84209e87c6 |
mm/gup: reliable R/O long-term pinning in COW mappings
We already support reliable R/O pinning of anonymous memory. However,
assume we end up pinning (R/O long-term) a pagecache page or the shared
zeropage inside a writable private ("COW") mapping. The next write access
will trigger a write-fault and replace the pinned page by an exclusive
anonymous page in the process page tables to break COW: the pinned page no
longer corresponds to the page mapped into the process' page table.
Now that FAULT_FLAG_UNSHARE can break COW on anything mapped into a
COW mapping, let's properly break COW first before R/O long-term
pinning something that's not an exclusive anon page inside a COW
mapping. FAULT_FLAG_UNSHARE will break COW and map an exclusive anon page
instead that can get pinned safely.
With this change, we can stop using FOLL_FORCE|FOLL_WRITE for reliable
R/O long-term pinning in COW mappings.
With this change, the new R/O long-term pinning tests for non-anonymous
memory succeed:
# [RUN] R/O longterm GUP pin ... with shared zeropage
ok 151 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd
ok 152 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with tmpfile
ok 153 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with huge zeropage
ok 154 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd hugetlb (2048 kB)
ok 155 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd hugetlb (1048576 kB)
ok 156 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with shared zeropage
ok 157 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd
ok 158 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with tmpfile
ok 159 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with huge zeropage
ok 160 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (2048 kB)
ok 161 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (1048576 kB)
ok 162 Longterm R/O pin is reliable
Note 1: We don't care about short-term R/O-pinning, because they have
snapshot semantics: they are not supposed to observe modifications that
happen after pinning.
As one example, assume we start direct I/O to read from a page and store
page content into a file: modifications to page content after starting
direct I/O are not guaranteed to end up in the file. So even if we'd pin
the shared zeropage, the end result would be as expected -- getting zeroes
stored to the file.
Note 2: For shared mappings we'll now always fallback to the slow path to
lookup the VMA when R/O long-term pining. While that's the necessary price
we have to pay right now, it's actually not that bad in practice: most
FOLL_LONGTERM users already specify FOLL_WRITE, for example, along with
FOLL_FORCE because they tried dealing with COW mappings correctly ...
Note 3: For users that use FOLL_LONGTERM right now without FOLL_WRITE,
such as VFIO, we'd now no longer pin the shared zeropage. Instead, we'd
populate exclusive anon pages that we can pin. There was a concern that
this could affect the memlock limit of existing setups.
For example, a VM running with VFIO could run into the memlock limit and
fail to run. However, we essentially had the same behavior already in
commit
|
||
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David Hildenbrand
|
cdc5021cda |
mm: add early FAULT_FLAG_UNSHARE consistency checks
For now, FAULT_FLAG_UNSHARE only applies to anonymous pages, which implies a COW mapping. Let's hide FAULT_FLAG_UNSHARE early if we're not dealing with a COW mapping, such that we treat it like a read fault as documented and don't have to worry about the flag throughout all fault handlers. While at it, centralize the check for mutual exclusion of FAULT_FLAG_UNSHARE and FAULT_FLAG_WRITE and just drop the check that either flag is set in the WP handler. Link: https://lkml.kernel.org/r/20221116102659.70287-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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David Hildenbrand
|
6a56ccbcf6 |
mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite
commit |
||
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David Hildenbrand
|
c27f479ef5 |
mm/huge_memory: try avoiding write faults when changing PMD protection
Let's replicate what we have for PTEs in can_change_pte_writable() also for PMDs. While this might look like a pure performance improvement, we'll us this to get rid of savedwrite handling in do_huge_pmd_numa_page() next. Place do_huge_pmd_numa_page() strategically good for that purpose. Note that MM_CP_TRY_CHANGE_WRITABLE is currently only set when we come via mprotect_fixup(). Link: https://lkml.kernel.org/r/20221108174652.198904-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Hugh Dickins <hughd@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Hugh Dickins
|
96d82deb74 |
mm,thp,rmap: clean up the end of __split_huge_pmd_locked()
It's hard to add a page_add_anon_rmap() into __split_huge_pmd_locked()'s HPAGE_PMD_NR set_pte_at() loop, without wincing at the "freeze" case's HPAGE_PMD_NR page_remove_rmap() loop below it. It's just a mistake to add rmaps in the "freeze" (insert migration entries prior to splitting huge page) case: the pmd_migration case already avoids doing that, so just follow its lead. page_add_ref() versus put_page() likewise. But why is one more put_page() needed in the "freeze" case? Because it's removing the pmd rmap, already removed when pmd_migration (and freeze and pmd_migration are mutually exclusive cases). Link: https://lkml.kernel.org/r/d43748aa-fece-e0b9-c4ab-f23c9ebc9011@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Carpenter <error27@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hugh Dickins
|
be5ef2d9b0 |
mm,thp,rmap: subpages_mapcount of PTE-mapped subpages
Patch series "mm,thp,rmap: rework the use of subpages_mapcount", v2. This patch (of 3): Following suggestion from Linus, instead of counting every PTE map of a compound page in subpages_mapcount, just count how many of its subpages are PTE-mapped: this yields the exact number needed for NR_ANON_MAPPED and NR_FILE_MAPPED stats, without any need for a locked scan of subpages; and requires updating the count less often. This does then revert total_mapcount() and folio_mapcount() to needing a scan of subpages; but they are inherently racy, and need no locking, so Linus is right that the scans are much better done there. Plus (unlike in 6.1 and previous) subpages_mapcount lets us avoid the scan in the common case of no PTE maps. And page_mapped() and folio_mapped() remain scanless and just as efficient with the new meaning of subpages_mapcount: those are the functions which I most wanted to remove the scan from. The updated page_dup_compound_rmap() is no longer suitable for use by anon THP's __split_huge_pmd_locked(); but page_add_anon_rmap() can be used for that, so long as its VM_BUG_ON_PAGE(!PageLocked) is deleted. Evidence is that this way goes slightly faster than the previous implementation for most cases; but significantly faster in the (now scanless) pmds after ptes case, which started out at 870ms and was brought down to 495ms by the previous series, now takes around 105ms. Link: https://lkml.kernel.org/r/a5849eca-22f1-3517-bf29-95d982242742@google.com Link: https://lkml.kernel.org/r/eec17e16-4e1-7c59-f1bc-5bca90dac919@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dan Carpenter <error27@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hugh Dickins
|
9bd3155ed8 |
mm,thp,rmap: lock_compound_mapcounts() on THP mapcounts
Fix the races in maintaining compound_mapcount, subpages_mapcount and
subpage _mapcount by using PG_locked in the first tail of any compound
page for a bit_spin_lock() on such modifications; skipping the usual
atomic operations on those fields in this case.
Bring page_remove_file_rmap() and page_remove_anon_compound_rmap() back
into page_remove_rmap() itself. Rearrange page_add_anon_rmap() and
page_add_file_rmap() and page_remove_rmap() to follow the same "if
(compound) {lock} else if (PageCompound) {lock} else {atomic}" pattern
(with a PageTransHuge in the compound test, like before, to avoid BUG_ONs
and optimize away that block when THP is not configured). Move all the
stats updates outside, after the bit_spin_locked section, so that it is
sure to be a leaf lock.
Add page_dup_compound_rmap() to manage compound locking versus atomics in
sync with the rest. In particular, hugetlb pages are still using the
atomics: to avoid unnecessary interference there, and because they never
have subpage mappings; but this exception can easily be changed.
Conveniently, page_dup_compound_rmap() turns out to suit an anon THP's
__split_huge_pmd_locked() too.
bit_spin_lock() is not popular with PREEMPT_RT folks: but PREEMPT_RT
sensibly excludes TRANSPARENT_HUGEPAGE already, so its only exposure is to
the non-hugetlb non-THP pte-mapped compound pages (with large folios being
currently dependent on TRANSPARENT_HUGEPAGE). There is never any scan of
subpages in this case; but we have chosen to use PageCompound tests rather
than PageTransCompound tests to gate the use of lock_compound_mapcounts(),
so that page_mapped() is correct on all compound pages, whether or not
TRANSPARENT_HUGEPAGE is enabled: could that be a problem for PREEMPT_RT,
when there is contention on the lock - under heavy concurrent forking for
example? If so, then it can be turned into a sleeping lock (like
folio_lock()) when PREEMPT_RT.
A simple 100 X munmap(mmap(2GB, MAP_SHARED|MAP_POPULATE, tmpfs), 2GB) took
18 seconds on small pages, and used to take 1 second on huge pages, but
now takes 115 milliseconds on huge pages. Mapping by pmds a second time
used to take 860ms and now takes 86ms; mapping by pmds after mapping by
ptes (when the scan is needed) used to take 870ms and now takes 495ms.
Mapping huge pages by ptes is largely unaffected but variable: between 5%
faster and 5% slower in what I've recorded. Contention on the lock is
likely to behave worse than contention on the atomics behaved.
Link: https://lkml.kernel.org/r/1b42bd1a-8223-e827-602f-d466c2db7d3c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Hugh Dickins
|
cb67f4282b |
mm,thp,rmap: simplify compound page mapcount handling
Compound page (folio) mapcount calculations have been different for anon and file (or shmem) THPs, and involved the obscure PageDoubleMap flag. And each huge mapping and unmapping of a file (or shmem) THP involved atomically incrementing and decrementing the mapcount of every subpage of that huge page, dirtying many struct page cachelines. Add subpages_mapcount field to the struct folio and first tail page, so that the total of subpage mapcounts is available in one place near the head: then page_mapcount() and total_mapcount() and page_mapped(), and their folio equivalents, are so quick that anon and file and hugetlb don't need to be optimized differently. Delete the unloved PageDoubleMap. page_add and page_remove rmap functions must now maintain the subpages_mapcount as well as the subpage _mapcount, when dealing with pte mappings of huge pages; and correct maintenance of NR_ANON_MAPPED and NR_FILE_MAPPED statistics still needs reading through the subpages, using nr_subpages_unmapped() - but only when first or last pmd mapping finds subpages_mapcount raised (double-map case, not the common case). But are those counts (used to decide when to split an anon THP, and in vmscan's pagecache_reclaimable heuristic) correctly maintained? Not quite: since page_remove_rmap() (and also split_huge_pmd()) is often called without page lock, there can be races when a subpage pte mapcount 0<->1 while compound pmd mapcount 0<->1 is scanning - races which the previous implementation had prevented. The statistics might become inaccurate, and even drift down until they underflow through 0. That is not good enough, but is better dealt with in a followup patch. Update a few comments on first and second tail page overlaid fields. hugepage_add_new_anon_rmap() has to "increment" compound_mapcount, but subpages_mapcount and compound_pincount are already correctly at 0, so delete its reinitialization of compound_pincount. A simple 100 X munmap(mmap(2GB, MAP_SHARED|MAP_POPULATE, tmpfs), 2GB) took 18 seconds on small pages, and used to take 1 second on huge pages, but now takes 119 milliseconds on huge pages. Mapping by pmds a second time used to take 860ms and now takes 92ms; mapping by pmds after mapping by ptes (when the scan is needed) used to take 870ms and now takes 495ms. But there might be some benchmarks which would show a slowdown, because tail struct pages now fall out of cache until final freeing checks them. Link: https://lkml.kernel.org/r/47ad693-717-79c8-e1ba-46c3a6602e48@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: James Houghton <jthoughton@google.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Andrew Morton
|
a38358c934 | Merge branch 'mm-hotfixes-stable' into mm-stable | ||
Peter Collingbourne
|
ef6458b1b6 |
mm: Add PG_arch_3 page flag
As with PG_arch_2, this flag is only allowed on 64-bit architectures due to the shortage of bits available. It will be used by the arm64 MTE code in subsequent patches. Signed-off-by: Peter Collingbourne <pcc@google.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Steven Price <steven.price@arm.com> [catalin.marinas@arm.com: added flag preserving in __split_huge_page_tail()] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Steven Price <steven.price@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221104011041.290951-5-pcc@google.com |
||
Catalin Marinas
|
b0284cd29a |
mm: Do not enable PG_arch_2 for all 64-bit architectures
Commit
|
||
Logan Gunthorpe
|
0f0892356f |
mm: allow multiple error returns in try_grab_page()
In order to add checks for P2PDMA memory into try_grab_page(), expand the error return from a bool to an int/error code. Update all the callsites handle change in usage. Also remove the WARN_ON_ONCE() call at the callsites seeing there already is a WARN_ON_ONCE() inside the function if it fails. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20221021174116.7200-2-logang@deltatee.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
||
Baolin Wang
|
fd4a7ac329 |
mm: migrate: try again if THP split is failed due to page refcnt
When creating a virtual machine, we will use memfd_create() to get a file descriptor which can be used to create share memory mappings using the mmap function, meanwhile the mmap() will set the MAP_POPULATE flag to allocate physical pages for the virtual machine. When allocating physical pages for the guest, the host can fallback to allocate some CMA pages for the guest when over half of the zone's free memory is in the CMA area. In guest os, when the application wants to do some data transaction with DMA, our QEMU will call VFIO_IOMMU_MAP_DMA ioctl to do longterm-pin and create IOMMU mappings for the DMA pages. However, when calling VFIO_IOMMU_MAP_DMA ioctl to pin the physical pages, we found it will be failed to longterm-pin sometimes. After some invetigation, we found the pages used to do DMA mapping can contain some CMA pages, and these CMA pages will cause a possible failure of the longterm-pin, due to failed to migrate the CMA pages. The reason of migration failure may be temporary reference count or memory allocation failure. So that will cause the VFIO_IOMMU_MAP_DMA ioctl returns error, which makes the application failed to start. I observed one migration failure case (which is not easy to reproduce) is that, the 'thp_migration_fail' count is 1 and the 'thp_split_page_failed' count is also 1. That means when migrating a THP which is in CMA area, but can not allocate a new THP due to memory fragmentation, so it will split the THP. However THP split is also failed, probably the reason is temporary reference count of this THP. And the temporary reference count can be caused by dropping page caches (I observed the drop caches operation in the system), but we can not drop the shmem page caches due to they are already dirty at that time. Especially for THP split failure, which is caused by temporary reference count, we can try again to mitigate the failure of migration in this case according to previous discussion [1]. [1] https://lore.kernel.org/all/470dc638-a300-f261-94b4-e27250e42f96@redhat.com/ Link: https://lkml.kernel.org/r/6784730480a1df82e8f4cba1ed088e4ac767994b.1666599848.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
9ee2c08627 |
mm/huge_memory: convert split_huge_pages_in_file() to use a folio
Patch series "Remove FGP_HEAD flag". We have just two users left of the FGP_HEAD flag and both of them are better off; sometimes startlingly so as a result of conversion to use folios. This patch (of 4): Removes a number of calls to compound_head() and a call to pagecache_get_page(). Link: https://lkml.kernel.org/r/20221019183332.2802139-1-willy@infradead.org Link: https://lkml.kernel.org/r/20221019183332.2802139-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
624a2c94f5 |
Partly revert "mm/thp: carry over dirty bit when thp splits on pmd"
Anatoly Pugachev reported sparc64 breakage on the patch:
https://lore.kernel.org/r/20221021160603.GA23307@u164.east.ru
The sparc64 impl of pte_mkdirty() is definitely slightly special in that
it leverages a code patching mechanism for sun4u/sun4v on relevant pgtable
entry operations.
Before having a clue of why the sparc64 is special and caused the patch to
SIGSEGV the processes, revert the patch for now. The swap path of dirty
bit inheritage is kept because that's using the swap shared code so we
assume it'll not be affected.
Link: https://lkml.kernel.org/r/Y1Wbi4yyVvDtg4zN@x1n
Fixes:
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|
Hugh Dickins
|
5aae9265ee |
mm: prep_compound_tail() clear page->private
Although page allocation always clears page->private in the first page or head page of an allocation, it has never made a point of clearing page->private in the tails (though 0 is often what is already there). But now commit |
||
Mel Gorman
|
71e2d666ef |
mm/huge_memory: do not clobber swp_entry_t during THP split
The following has been observed when running stressng mmap since commit |
||
Zach O'Keefe
|
7c6c6cc4d3 |
mm/shmem: add flag to enforce shmem THP in hugepage_vma_check()
Patch series "mm: add file/shmem support to MADV_COLLAPSE", v4. This series builds on top of the previous "mm: userspace hugepage collapse" series which introduced the MADV_COLLAPSE madvise mode and added support for private, anonymous mappings[2], by adding support for file and shmem backed memory to CONFIG_READ_ONLY_THP_FOR_FS=y kernels. File and shmem support have been added with effort to align with existing MADV_COLLAPSE semantics and policy decisions[3]. Collapse of shmem-backed memory ignores kernel-guiding directives and heuristics including all sysfs settings (transparent_hugepage/shmem_enabled), and tmpfs huge= mount options (shmem always supports large folios). Like anonymous mappings, on successful return of MADV_COLLAPSE on file/shmem memory, the contents of memory mapped by the addresses provided will be synchronously pmd-mapped THPs. This functionality unlocks two important uses: (1) Immediately back executable text by THPs. Current support provided by CONFIG_READ_ONLY_THP_FOR_FS may take a long time on a large system which might impair services from serving at their full rated load after (re)starting. Tricks like mremap(2)'ing text onto anonymous memory to immediately realize iTLB performance prevents page sharing and demand paging, both of which increase steady state memory footprint. Now, we can have the best of both worlds: Peak upfront performance and lower RAM footprints. (2) userfaultfd-based live migration of virtual machines satisfy UFFD faults by fetching native-sized pages over the network (to avoid latency of transferring an entire hugepage). However, after guest memory has been fully copied to the new host, MADV_COLLAPSE can be used to immediately increase guest performance. khugepaged has received a small improvement by association and can now detect and collapse pte-mapped THPs. However, there is still work to be done along the file collapse path. Compound pages of arbitrary order still needs to be supported and THP collapse needs to be converted to using folios in general. Eventually, we'd like to move away from the read-only and executable-mapped constraints currently imposed on eligible files and support any inode claiming huge folio support. That said, I think the series as-is covers enough to claim that MADV_COLLAPSE supports file/shmem memory. Patches 1-3 Implement the guts of the series. Patch 4 Is a tracepoint for debugging. Patches 5-9 Refactor existing khugepaged selftests to work with new memory types + new collapse tests. Patch 10 Adds a userfaultfd selftest mode to mimic a functional test of UFFDIO_REGISTER_MODE_MINOR+MADV_COLLAPSE live migration. (v4 note: "userfaultfd shmem" selftest is failing as of Sep 22 mm-unstable) [1] https://lore.kernel.org/linux-mm/YyiK8YvVcrtZo0z3@google.com/ [2] https://lore.kernel.org/linux-mm/20220706235936.2197195-1-zokeefe@google.com/ [3] https://lore.kernel.org/linux-mm/YtBmhaiPHUTkJml8@google.com/ [4] https://lore.kernel.org/linux-mm/20220922222731.1124481-1-zokeefe@google.com/ [5] https://lore.kernel.org/linux-mm/20220922184651.1016461-1-zokeefe@google.com/ This patch (of 10): Extend 'mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()' to shmem, allowing callers to ignore /sys/kernel/transparent_hugepage/shmem_enabled and tmpfs huge= mount. This is intended to be used by MADV_COLLAPSE, and the rationale is analogous to the anon/file case: MADV_COLLAPSE is not coupled to directives that advise the kernel's decisions on when THPs should be considered eligible. shmem/tmpfs always claims large folio support, regardless of sysfs or mount options. [shy828301@gmail.com: test shmem_huge_force explicitly] Link: https://lore.kernel.org/linux-mm/CAHbLzko3A5-TpS0BgBeKkx5cuOkWgLvWXQH=TdgW-baO4rPtdg@mail.gmail.com/ Link: https://lkml.kernel.org/r/20220922224046.1143204-1-zokeefe@google.com Link: https://lkml.kernel.org/r/20220907144521.3115321-2-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-2-zokeefe@google.com Signed-off-by: Zach O'Keefe <zokeefe@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Chris Kennelly <ckennelly@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Liu Shixin
|
f498150208 |
mm/huge_memory: prevent THP_ZERO_PAGE_ALLOC increased twice
A user who reads THP_ZERO_PAGE_ALLOC may be more concerned about the huge zero pages that are really allocated for thp. It is misleading to increase THP_ZERO_PAGE_ALLOC twice if two threads call get_huge_zero_page concurrently. Don't increase the value if the huge page is not really used. Update Documentation/admin-guide/mm/transhuge.rst to suit. Link: https://lkml.kernel.org/r/20220909021653.3371879-1-liushixin2@huawei.com Signed-off-by: Liu Shixin <liushixin2@huawei.com> Cc: Alexander Potapenko <glider@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Matthew Wilcox (Oracle)
|
29eea9b5a9 |
mm: convert page_get_anon_vma() to folio_get_anon_vma()
With all callers now passing in a folio, rename the function and convert all callers. Removes a couple of calls to compound_head() and a reference to page->mapping. Link: https://lkml.kernel.org/r/20220902194653.1739778-55-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Matthew Wilcox (Oracle)
|
684555aacc |
huge_memory: convert unmap_page() to unmap_folio()
Remove a folio->page->folio conversion. Link: https://lkml.kernel.org/r/20220902194653.1739778-54-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Matthew Wilcox (Oracle)
|
3e9a13daa6 |
huge_memory: convert split_huge_page_to_list() to use a folio
Saves many calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-53-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Matthew Wilcox (Oracle)
|
2fad3d14b9 |
huge_memory: convert do_huge_pmd_wp_page() to use a folio
Removes many calls to compound_head(). Does not remove the assumption that a folio may not be larger than a PMD. Link: https://lkml.kernel.org/r/20220902194653.1739778-43-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
David Hildenbrand
|
474098edac |
mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()
Patch series "mm: minor cleanups around NUMA hinting". Working on some GUP cleanups (e.g., getting rid of some FOLL_ flags) and preparing for other GUP changes (getting rid of FOLL_FORCE|FOLL_WRITE for for taking a R/O longterm pin), this is something I can easily send out independently. Get rid of FOLL_NUMA, allow FOLL_FORCE access to PROT_NONE mapped pages in GUP-fast, and fixup some documentation around NUMA hinting. This patch (of 3): No need for a special flag that is not even properly documented to be internal-only. Let's just factor this check out and get rid of this flag. The separate function has the nice benefit that we can centralize comments. Link: https://lkml.kernel.org/r/20220825164659.89824-2-david@redhat.com Link: https://lkml.kernel.org/r/20220825164659.89824-1-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Haiyue Wang
|
f7091ed64e |
mm: fix the handling Non-LRU pages returned by follow_page
The handling Non-LRU pages returned by follow_page() jumps directly, it
doesn't call put_page() to handle the reference count, since 'FOLL_GET'
flag for follow_page() has get_page() called. Fix the zone device page
check by handling the page reference count correctly before returning.
And as David reviewed, "device pages are never PageKsm pages". Drop this
zone device page check for break_ksm().
Since the zone device page can't be a transparent huge page, so drop the
redundant zone device page check for split_huge_pages_pid(). (by Miaohe)
Link: https://lkml.kernel.org/r/20220823135841.934465-3-haiyue.wang@intel.com
Fixes:
|
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|
Matthew Wilcox (Oracle)
|
685405020b |
mm/khugepaged: stop using vma linked list
Use vma iterator & find_vma() instead of vma linked list. Link: https://lkml.kernel.org/r/20220906194824.2110408-53-Liam.Howlett@oracle.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Aneesh Kumar K.V
|
467b171af8 |
mm/demotion: update node_is_toptier to work with memory tiers
With memory tier support we can have memory only NUMA nodes in the top tier from which we want to avoid promotion tracking NUMA faults. Update node_is_toptier to work with memory tiers. All NUMA nodes are by default top tier nodes. With lower(slower) memory tiers added we consider all memory tiers above a memory tier having CPU NUMA nodes as a top memory tier [sj@kernel.org: include missed header file, memory-tiers.h] Link: https://lkml.kernel.org/r/20220820190720.248704-1-sj@kernel.org [akpm@linux-foundation.org: mm/memory.c needs linux/memory-tiers.h] [aneesh.kumar@linux.ibm.com: make toptier_distance inclusive upper bound of toptiers] Link: https://lkml.kernel.org/r/20220830081457.118960-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-10-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Wei Xu <weixugc@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hesham Almatary <hesham.almatary@huawei.com> Cc: Jagdish Gediya <jvgediya.oss@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yu Zhao
|
ec1c86b25f |
mm: multi-gen LRU: groundwork
Evictable pages are divided into multiple generations for each lruvec. The youngest generation number is stored in lrugen->max_seq for both anon and file types as they are aged on an equal footing. The oldest generation numbers are stored in lrugen->min_seq[] separately for anon and file types as clean file pages can be evicted regardless of swap constraints. These three variables are monotonically increasing. Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits in order to fit into the gen counter in folio->flags. Each truncated generation number is an index to lrugen->lists[]. The sliding window technique is used to track at least MIN_NR_GENS and at most MAX_NR_GENS generations. The gen counter stores a value within [1, MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it stores 0. There are two conceptually independent procedures: "the aging", which produces young generations, and "the eviction", which consumes old generations. They form a closed-loop system, i.e., "the page reclaim". Both procedures can be invoked from userspace for the purposes of working set estimation and proactive reclaim. These techniques are commonly used to optimize job scheduling (bin packing) in data centers [1][2]. To avoid confusion, the terms "hot" and "cold" will be applied to the multi-gen LRU, as a new convention; the terms "active" and "inactive" will be applied to the active/inactive LRU, as usual. The protection of hot pages and the selection of cold pages are based on page access channels and patterns. There are two access channels: one through page tables and the other through file descriptors. The protection of the former channel is by design stronger because: 1. The uncertainty in determining the access patterns of the former channel is higher due to the approximation of the accessed bit. 2. The cost of evicting the former channel is higher due to the TLB flushes required and the likelihood of encountering the dirty bit. 3. The penalty of underprotecting the former channel is higher because applications usually do not prepare themselves for major page faults like they do for blocked I/O. E.g., GUI applications commonly use dedicated I/O threads to avoid blocking rendering threads. There are also two access patterns: one with temporal locality and the other without. For the reasons listed above, the former channel is assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is present; the latter channel is assumed to follow the latter pattern unless outlying refaults have been observed [3][4]. The next patch will address the "outlying refaults". Three macros, i.e., LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in this patch to make the entire patchset less diffy. A page is added to the youngest generation on faulting. The aging needs to check the accessed bit at least twice before handing this page over to the eviction. The first check takes care of the accessed bit set on the initial fault; the second check makes sure this page has not been used since then. This protocol, AKA second chance, requires a minimum of two generations, hence MIN_NR_GENS. [1] https://dl.acm.org/doi/10.1145/3297858.3304053 [2] https://dl.acm.org/doi/10.1145/3503222.3507731 [3] https://lwn.net/Articles/495543/ [4] https://lwn.net/Articles/815342/ Link: https://lkml.kernel.org/r/20220918080010.2920238-6-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |