22712 Commits

Author SHA1 Message Date
Kefeng Wang
15b0c79cfa mm: migrate_device: unify migrate folio for MIGRATE_SYNC_NO_COPY
The __migrate_device_pages() won't copy page so MIGRATE_SYNC_NO_COPY
passed into migrate_folio()/migrate_folio_extra(), actually a easy way is
just to call folio_migrate_mapping()/folio_migrate_flags(), converting it
to unify and simplify the migrate device pages, which also remove the only
call for MIGRATE_SYNC_NO_COPY.

Link: https://lkml.kernel.org/r/20240524052843.182275-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:00 -07:00
Kefeng Wang
6aaaef5b6f mm: migrate_device: use a newfolio in __migrate_device_pages()
Use a newfolio instead of newpage and convert to more folio api in
__migrate_device_pages().

Link: https://lkml.kernel.org/r/20240524052843.182275-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:30:00 -07:00
Kefeng Wang
01878f10f8 mm: migrate: simplify __buffer_migrate_folio()
Patch series "mm: cleanup MIGRATE_SYNC_NO_COPY mode".

Commit 2916ecc0f9d4 ("mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY")
introduce a new MIGRATE_SYNC_NO_COPY mode to allow to offload the copy to
a device DMA engine, which is only used __migrate_device_pages() to decide
whether or not copy the old page, and the MIGRATE_SYNC_NO_COPY mode only
used in hmm, a easy way is just to call the folio_migrate_mapping() and
folio_migrate_flags(), which help to remove the MIGRATE_SYNC_NO_COPY mode.


This patch (of 5):

Use filemap_migrate_folio() helper to simplify __buffer_migrate_folio().

Link: https://lkml.kernel.org/r/20240524052843.182275-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240524052843.182275-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:59 -07:00
Matthew Wilcox (Oracle)
06668257a3 mm: remove page_mapping()
All callers are now converted, delete this compatibility wrapper.  Also
fix up some comments which referred to page_mapping.

Link: https://lkml.kernel.org/r/20240423225552.4113447-7-willy@infradead.org
Link: https://lkml.kernel.org/r/20240524181813.698813-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:59 -07:00
Kefeng Wang
ffc3c8a631 mm: memcontrol: remove page_memcg()
The page_memcg() only called by mod_memcg_page_state(), so squash it to
cleanup page_memcg().

Link: https://lkml.kernel.org/r/20240524014950.187805-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:59 -07:00
Yifei Li
1e25501dbc mm/memory-failure: use helper llist_for_each_entry()
Change the llist_for_each_entry_safe function to the llist_for_each_entry
function and delete the next variable.  Because the linked list is not
modified,the llist_for_each_entry_safe function is not required.  No
functional changes are intended.

Link: https://lkml.kernel.org/r/20240513075830.2611-1-liyifei28@huawei.com
Signed-off-by: Yifei Li <liyifei28@huawei.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:59 -07:00
Jeff Johnson
a831896a0c mm/zsmalloc: add MODULE_DESCRIPTION()
Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in mm/zsmalloc.o

Link: https://lkml.kernel.org/r/20240513-mm-md-v1-4-8c20e7d26842@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:59 -07:00
Jeff Johnson
eed4c0e5e9 mm/kfence: add MODULE_DESCRIPTION()
Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in mm/kfence/kfence_test.o

Link: https://lkml.kernel.org/r/20240513-mm-md-v1-3-8c20e7d26842@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Jeff Johnson
669de9f2ea mm/dmapool: add MODULE_DESCRIPTION()
Fix the 'make W=1' warning:

WARNING: modpost: missing MODULE_DESCRIPTION() in mm/dmapool_test.o

Link: https://lkml.kernel.org/r/20240513-mm-md-v1-2-8c20e7d26842@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Jeff Johnson
2f57ced636 mm/hwpoison: add MODULE_DESCRIPTION()
Patch series "mm: add missing MODULE_DESCRIPTION() macros".

This fixes the instances of "WARNING: modpost: missing
MODULE_DESCRIPTION()" that I'm seeing in mm/.


This patch (of 4):

Fix the 'make W=1' warning:
WARNING: modpost: missing MODULE_DESCRIPTION() in mm/hwpoison-inject.o

Link: https://lkml.kernel.org/r/20240513-mm-md-v1-0-8c20e7d26842@quicinc.com
Link: https://lkml.kernel.org/r/20240513-mm-md-v1-1-8c20e7d26842@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Eric Chanudet
188f87f264 mm/mm_init: use node's number of cpus in deferred_page_init_max_threads
x86_64 is already using the node's cpu as maximum threads.  Make that the
default for all archs setting DEFERRED_STRUCT_PAGE_INIT.

This returns to the behavior prior making the function arch-specific with
commit ecd096506922 ("mm: make deferred init's max threads
arch-specific").

Setting DEFERRED_STRUCT_PAGE_INIT and testing on a few arm64 platforms
shows faster deferred_init_memmap completions:

|         | x13s        | SA8775p-ride | Ampere R137-P31 | Ampere HR330 |
|         | Metal, 32GB | VM, 36GB     | VM, 58GB        | Metal, 128GB |
|         | 8cpus       | 8cpus        | 8cpus           | 32cpus       |
|---------|-------------|--------------|-----------------|--------------|
| threads |  ms     (%) | ms       (%) |  ms         (%) |  ms      (%) |
|---------|-------------|--------------|-----------------|--------------|
| 1       | 108    (0%) | 72      (0%) | 224        (0%) | 324     (0%) |
| cpus    |  24  (-77%) | 36    (-50%) |  40      (-82%) |  56   (-82%) |

Michael Ellerman reported:

: On a machine here (1TB, 40 cores, 4KB pages) the existing code gives:
: 
:   [    0.500124] node 2 deferred pages initialised in 210ms
:   [    0.515790] node 3 deferred pages initialised in 230ms
:   [    0.516061] node 0 deferred pages initialised in 230ms
:   [    0.516522] node 7 deferred pages initialised in 230ms
:   [    0.516672] node 4 deferred pages initialised in 230ms
:   [    0.516798] node 6 deferred pages initialised in 230ms
:   [    0.517051] node 5 deferred pages initialised in 230ms
:   [    0.523887] node 1 deferred pages initialised in 240ms
: 
: vs with the patch:
: 
:   [    0.379613] node 0 deferred pages initialised in 90ms
:   [    0.380388] node 1 deferred pages initialised in 90ms
:   [    0.380540] node 4 deferred pages initialised in 100ms
:   [    0.390239] node 6 deferred pages initialised in 100ms
:   [    0.390249] node 2 deferred pages initialised in 100ms
:   [    0.390786] node 3 deferred pages initialised in 110ms
:   [    0.396721] node 5 deferred pages initialised in 110ms
:   [    0.397095] node 7 deferred pages initialised in 110ms
: 
: Which is a nice speedup.

[echanude@redhat.com: v3]
  Link: https://lkml.kernel.org/r/20240528185455.643227-4-echanude@redhat.com
Link: https://lkml.kernel.org/r/20240522203758.626932-4-echanude@redhat.com
Signed-off-by: Eric Chanudet <echanude@redhat.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Mateusz Guzik
3577dbb192 mm: batch unlink_file_vma calls in free_pgd_range
Execs of dynamically linked binaries at 20-ish cores are bottlenecked on
the i_mmap_rwsem semaphore, while the biggest singular contributor is
free_pgd_range inducing the lock acquire back-to-back for all consecutive
mappings of a given file.

Tracing the count of said acquires while building the kernel shows:
[1, 2)     799579 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[2, 3)          0 |                                                    |
[3, 4)       3009 |                                                    |
[4, 5)       3009 |                                                    |
[5, 6)     326442 |@@@@@@@@@@@@@@@@@@@@@                               |

So in particular there were 326442 opportunities to coalesce 5 acquires
into 1.

Doing so increases execs per second by 4% (~50k to ~52k) when running
the benchmark linked below.

The lock remains the main bottleneck, I have not looked at other spots
yet.

Bench can be found here:
http://apollo.backplane.com/DFlyMisc/doexec.c

$ cc -O2 -o shared-doexec doexec.c
$ ./shared-doexec $(nproc)

Note this particular test makes sure binaries are separate, but the
loader is shared.

Stats collected on the patched kernel (+ "noinline") with:
bpftrace -e 'kprobe:unlink_file_vma_batch_process
{ @ = lhist(((struct unlink_vma_file_batch *)arg0)->count, 0, 8, 1); }'

Link: https://lkml.kernel.org/r/20240521234321.359501-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Jane Chu
1a3798dece mm/memory-failure: send SIGBUS in the event of thp split fail
While handling hwpoison in a THP page, it is possible that
try_to_split_thp_page() fails.  For example, when the THP page has been
RDMA pinned.  At this point, the kernel cannot isolate the poisoned THP
page, all it could do is to send a SIGBUS to the user process with
meaningful payload to give user-level recovery a chance.

Link: https://lkml.kernel.org/r/20240524215306.2705454-6-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Jane Chu
9b0ab153d7 mm/memory-failure: move hwpoison_filter() higher up
Move hwpoison_filter() higher up as there is no need to spend a lot cycles
only to find out later that the page is supposed to be skipped from
hwpoison handling.

Link: https://lkml.kernel.org/r/20240524215306.2705454-5-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:58 -07:00
Jane Chu
b8b9488d50 mm/memory-failure: improve memory failure action_result messages
Added two explicit MF_MSG messages describing failure in
get_hwpoison_page.  Attemped to document the definition of various action
names, and made a few adjustment to the action_result() calls.

Link: https://lkml.kernel.org/r/20240524215306.2705454-4-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:57 -07:00
Jane Chu
6680252629 mm/madvise: add MF_ACTION_REQUIRED to madvise(MADV_HWPOISON)
The soft hwpoison injector via madvise(MADV_HWPOISON) operates in a
synchrous way in a sense, the injector is also a process under test, and
should it have the poisoned page mapped in its address space, it should
get killed as much as in a real UE situation.  Doing so align with what
the madvise(2) man page says: " "This operation may result in the calling
process receiving a SIGBUS and the page being unmapped."

Link: https://lkml.kernel.org/r/20240524215306.2705454-3-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <oalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:57 -07:00
Jane Chu
aa298fdf53 mm/memory-failure: try to send SIGBUS even if unmap failed
Patch series "Enhance soft hwpoison handling and injection", v4.

This series is aimed at the following enhancements:

- Let one hwpoison injector, that is, madvise(MADV_HWPOISON) to behave
  more like as if a real UE occurred.  Because the other two injectors
  such as hwpoison-inject and the 'einj' on x86 can't, and it seems to me
  we need a better simulation to real UE scenario.
- For years, if the kernel is unable to unmap a hwpoisoned page, it send
  a SIGKILL instead of SIGBUS to prevent user process from potentially
  accessing the page again.  But in doing so, the user process also lose
  important information: vaddr, for recovery.  Fortunately, the kernel
  already has code to kill process re-accessing a hwpoisoned page, so
  remove the '!unmap_success' check.
- Right now, if a thp page under GUP longterm pin is hwpoisoned, and
  kernel cannot split the thp page, memory-failure simply ignores the UE
  and returns.  That's not ideal, it could deliver a SIGBUS with useful
  information for userspace recovery.


This patch (of 5):

For years when it comes down to kill a process due to hwpoison, a SIGBUS
is delivered only if unmap has been successful.  Otherwise, a SIGKILL is
delivered.  And the reason for that is to prevent the involved process
from accessing the hwpoisoned page again.

Since then a lot has changed, a hwpoisoned page is marked and upon being
re-accessed, the memory-failure handler invokes kill_accessing_process()
to kill the process immediately.  So let's take out the '!unmap_success'
factor and try to deliver SIGBUS if possible.

Link: https://lkml.kernel.org/r/20240524215306.2705454-1-jane.chu@oracle.com
Link: https://lkml.kernel.org/r/20240524215306.2705454-2-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <oalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:57 -07:00
Bang Li
6faa49d1c4 mm: use update_mmu_tlb_range() to simplify code
Let us simplify the code by update_mmu_tlb_range().

Link: https://lkml.kernel.org/r/20240522061204.117421-4-libang.li@antgroup.com
Signed-off-by: Bang Li <libang.li@antgroup.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:57 -07:00
David Hildenbrand
fce831c920 mm/memory: cleanly support zeropage in vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()
For now we only get the (small) zeropage mapped to user space in four
cases (excluding VM_PFNMAP mappings, such as /proc/vmstat):

(1) Read page faults in anonymous VMAs (MAP_PRIVATE|MAP_ANON):
    do_anonymous_page() will not refcount it and map it pte_mkspecial()
(2) UFFDIO_ZEROPAGE on anonymous VMA or COW mapping of shmem
    (MAP_PRIVATE). mfill_atomic_pte_zeropage() will not refcount it and
    map it pte_mkspecial().
(3) KSM in mergeable VMA (anonymous VMA or COW mapping).
    cmp_and_merge_page() will not refcount it and map it
    pte_mkspecial().
(4) FSDAX as an optimization for holes.
    vmf_insert_mixed()->__vm_insert_mixed() might end up calling
    insert_page() without CONFIG_ARCH_HAS_PTE_SPECIAL, refcounting the
    zeropage and not mapping it pte_mkspecial(). With
    CONFIG_ARCH_HAS_PTE_SPECIAL, we'll call insert_pfn() where we will
    not refcount it and map it pte_mkspecial().

In case (4), we might not have VM_MIXEDMAP set: while fs/fuse/dax.c sets
VM_MIXEDMAP, we removed it for ext4 fsdax in commit e1fb4a086495 ("dax:
remove VM_MIXEDMAP for fsdax and device dax") and for XFS in commit
e1fb4a086495 ("dax: remove VM_MIXEDMAP for fsdax and device dax").

Without CONFIG_ARCH_HAS_PTE_SPECIAL and with VM_MIXEDMAP, vm_normal_page()
would currently return the zeropage.  We'll refcount the zeropage when
mapping and when unmapping.

Without CONFIG_ARCH_HAS_PTE_SPECIAL and without VM_MIXEDMAP,
vm_normal_page() would currently refuse to return the zeropage.  So we'd
refcount it when mapping but not when unmapping it ...  do we have fsdax
without CONFIG_ARCH_HAS_PTE_SPECIAL in practice?  Hard to tell.

Independent of that, we should never refcount the zeropage when we might
be holding that reference for a long time, because even without an
accounting imbalance we might overflow the refcount.  As there is interest
in using the zeropage also in other VM_MIXEDMAP mappings, let's add clean
support for that in the cases where it makes sense:

(A) Never refcount the zeropage when mapping it:

In insert_page(), special-case the zeropage, do not refcount it, and use
pte_mkspecial().  Don't involve insert_pfn(), adjusting insert_page()
looks cleaner than branching off to insert_pfn().

(B) Never refcount the zeropage when unmapping it:

In vm_normal_page(), also don't return the zeropage in a VM_MIXEDMAP
mapping without CONFIG_ARCH_HAS_PTE_SPECIAL.  Add a VM_WARN_ON_ONCE()
sanity check if we'd ever return the zeropage, which could happen if
someone forgets to set pte_mkspecial() when mapping the zeropage. 
Document that.

(C) Allow the zeropage only where reasonable

s390x never wants the zeropage in some processes running legacy KVM guests
that make use of storage keys.  So disallow that.

Further, using the zeropage in COW mappings is unproblematic (just what we
do for other COW mappings), because FAULT_FLAG_UNSHARE can just unshare it
and GUP with FOLL_LONGTERM would work as expected.

Similarly, mappings that can never have writable PTEs (implying no write
faults) are also not problematic, because nothing could end up mapping the
PTE writable by mistake later.  But in case we could have writable PTEs,
we'll only allow the zeropage in FSDAX VMAs, that are incompatible with
GUP and are blocked there completely.

We'll always require the zeropage to be mapped with pte_special(). 
GUP-fast will reject the zeropage that way, but GUP-slow will allow it. 
(Note that GUP does not refcount the zeropage with FOLL_PIN, because there
were issues with overflowing the refcount in the past).

Add sanity checks to can_change_pte_writable() and wp_page_reuse(), to
catch early during testing if we'd ever find a zeropage unexpectedly in
code that wants to upgrade write permissions.

Convert the BUG_ON in vm_mixed_ok() to an ordinary check and simply fail
with VM_FAULT_SIGBUS, like we do for other sanity checks.  Drop the stale
comment regarding reserved pages from insert_page().

Note that:
* we won't mess with VM_PFNMAP mappings for now. remap_pfn_range() and
  vmf_insert_pfn() would allow the zeropage in some cases and
  not refcount it.
* vmf_insert_pfn*() will reject the zeropage in VM_MIXEDMAP
  mappings and we'll leave that alone for now. People can simply use
  one of the other interfaces.
* we won't bother with the huge zeropage for now. It's never
  PTE-mapped and also GUP does not special-case it yet.

Link: https://lkml.kernel.org/r/20240522125713.775114-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:56 -07:00
David Hildenbrand
11b914ee9e mm/memory: move page_count() check into validate_page_before_insert()
Patch series "mm/memory: cleanly support zeropage in vm_insert_page*(),
vm_map_pages*() and vmf_insert_mixed()", v2.

There is interest in mapping zeropages via vm_insert_pages() [1] into
MAP_SHARED mappings.

For now, we only get zeropages in MAP_SHARED mappings via
vmf_insert_mixed() from FSDAX code, and I think it's a bit shaky in some
cases because we refcount the zeropage when mapping it but not necessarily
always when unmapping it ...  and we should actually never refcount it.

It's all a bit tricky, especially how zeropages in MAP_SHARED mappings
interact with GUP (FOLL_LONGTERM), mprotect(), write-faults and s390x
forbidding the shared zeropage (rewrite [2] s now upstream).

This series tries to take the careful approach of only allowing the
zeropage where it is likely safe to use (which should cover the existing
FSDAX use case and [1]), preventing that it could accidentally get mapped
writable during a write fault, mprotect() etc, and preventing issues with
FOLL_LONGTERM in the future with other users.

Tested with a patch from Vincent that uses the zeropage in context of
[1].

[1] https://lkml.kernel.org/r/20240430111354.637356-1-vdonnefort@google.com
[2] https://lkml.kernel.org/r/20240411161441.910170-1-david@redhat.com


This patch (of 3):

We'll now also cover the case where insert_page() is called from
__vm_insert_mixed(), which sounds like the right thing to do.

Link: https://lkml.kernel.org/r/20240522125713.775114-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:56 -07:00
Kairui Song
7aad25b4b4 mm/swap: reduce swap cache search space
Currently we use one swap_address_space for every 64M chunk to reduce lock
contention, this is like having a set of smaller swap files inside one
swap device.  But when doing swap cache look up or insert, we are still
using the offset of the whole large swap device.  This is OK for
correctness, as the offset (key) is unique.

But Xarray is specially optimized for small indexes, it creates the radix
tree levels lazily to be just enough to fit the largest key stored in one
Xarray.  So we are wasting tree nodes unnecessarily.

For 64M chunk it should only take at most 3 levels to contain everything. 
But if we are using the offset from the whole swap device, the offset
(key) value will be way beyond 64M, and so will the tree level.

Optimize this by using a new helper swap_cache_index to get a swap entry's
unique offset in its own 64M swap_address_space.

I see a ~1% performance gain in benchmark and actual workload with high
memory pressure.

Test with `time memhog 128G` inside a 8G memcg using 128G swap (ramdisk
with SWP_SYNCHRONOUS_IO dropped, tested 3 times, results are stable.  The
test result is similar but the improvement is smaller if
SWP_SYNCHRONOUS_IO is enabled, as swap out path can never skip swap
cache):

Before:
6.07user 250.74system 4:17.26elapsed 99%CPU (0avgtext+0avgdata 8373376maxresident)k
0inputs+0outputs (55major+33555018minor)pagefaults 0swaps

After (1.8% faster):
6.08user 246.09system 4:12.58elapsed 99%CPU (0avgtext+0avgdata 8373248maxresident)k
0inputs+0outputs (54major+33555027minor)pagefaults 0swaps

Similar result with MySQL and sysbench using swap:
Before:
94055.61 qps

After (0.8% faster):
94834.91 qps

Radix tree slab usage is also very slightly lower.

Link: https://lkml.kernel.org/r/20240521175854.96038-12-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:56 -07:00
Kairui Song
05b0c7edad mm: drop page_index and simplify folio_index
There are two helpers for retrieving the index within address space for
mixed usage of swap cache and page cache:

- page_index
- folio_index

This commit drops page_index, as we have eliminated all users, and
converts folio_index's helper __page_file_index to use folio to avoid the
page conversion.

Link: https://lkml.kernel.org/r/20240521175854.96038-11-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:55 -07:00
Kairui Song
545ebe71d3 mm/swap: get the swap device offset directly
folio_file_pos and page_file_offset are for mixed usage of swap cache and
page cache, it can't be page cache here, so introduce a new helper to get
the swap offset in swap device directly.

Need to include swapops.h in mm/swap.h to ensure swp_offset is always
defined before use.

Link: https://lkml.kernel.org/r/20240521175854.96038-9-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:55 -07:00
Kemeng Shi
8246291ecc writeback: factor out balance_wb_limits to remove repeated code
Factor out balance_wb_limits to remove repeated code

[shikemeng@huaweicloud.com: add comment]
  Link: https://lkml.kernel.org/r/20240606033547.344376-1-shikemeng@huaweicloud.com
[akpm@linux-foundation.org: s/fileds/fields/ in comment]
Link: https://lkml.kernel.org/r/20240514125254.142203-9-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:54 -07:00
Kemeng Shi
236d0f16eb writeback: factor out wb_dirty_exceeded to remove repeated code
Factor out wb_dirty_exceeded to remove repeated code

Link: https://lkml.kernel.org/r/20240514125254.142203-8-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:54 -07:00
Kemeng Shi
8c9918dedf writeback: factor out balance_domain_limits to remove repeated code
Factor out balance_domain_limits to remove repeated code.

Link: https://lkml.kernel.org/r/20240514125254.142203-7-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:54 -07:00
Kemeng Shi
2530e2399b writeback: factor out wb_dirty_freerun to remove more repeated freerun code
Factor out wb_dirty_freerun to remove more repeated freerun code.

Link: https://lkml.kernel.org/r/20240514125254.142203-6-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:54 -07:00
Kemeng Shi
9bb48a7038 writeback: factor out code of freerun to remove repeated code
Factor out code of freerun into new helper functions domain_poll_intv and
domain_dirty_freerun to remove repeated code.

Link: https://lkml.kernel.org/r/20240514125254.142203-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:54 -07:00
Kemeng Shi
6e20832968 writeback: factor out domain_over_bg_thresh to remove repeated code
Factor out domain_over_bg_thresh from wb_over_bg_thresh to remove repeated
code.

Link: https://lkml.kernel.org/r/20240514125254.142203-4-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:54 -07:00
Kemeng Shi
ba62d5cfe1 writeback: add general function domain_dirty_avail to calculate dirty and avail of domain
Add general function domain_dirty_avail to calculate dirty and avail for
either dirty limit or background writeback in either global domain or wb
domain.

Link: https://lkml.kernel.org/r/20240514125254.142203-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:53 -07:00
Kemeng Shi
7c0c629be5 writeback: factor out wb_bg_dirty_limits to remove repeated code
Patch series "Add helper functions to remove repeated code and improve
readability of cgroup writeback", v2.

This series adds a lot of helpers to remove repeated code between domain
and wb; dirty limit and dirty background; global domain and wb domain. 
The helpers also improve readability.  More details can be found in the
respective patches.

A simple domain hierarchy is tested:
global domain (> 20G)
	|
cgroup domain1(10G)
	|
	wb1
	|
	fio

Test steps:
/* make it easy to observe */
echo 300000 > /proc/sys/vm/dirty_expire_centisecs
echo 3000 > /proc/sys/vm/dirty_writeback_centisecs

/* create cgroup domain */
cd /sys/fs/cgroup
echo "+memory +io" > cgroup.subtree_control
mkdir group1
cd group1
echo 10G > memory.high
echo 10G > memory.max
echo $$ > cgroup.procs
mkfs.ext4 -F /dev/vdb
mount /dev/vdb /bdi1/

/* run fio to generate dirty pages */
fio -name test -filename=/bdi1/file -size=xxx -ioengine=libaio -bs=4K \
-iodepth=1 -rw=write -direct=0 --time_based -runtime=600 -invalidate=0

When fio size is 1G, the wb is in freerun state and dirty pages are only
written back when dirty inode is expired after 30 seconds.  When fio size
is 2G, the dirty pages keep being written back and bandwidth of fio is
limited.


This patch (of 8):

Similar to wb_dirty_limits which calculates dirty and thresh of wb,
wb_bg_dirty_limits calculates background dirty and background thresh of
wb.  With wb_bg_dirty_limits, we could remove repeated code in
wb_over_bg_thresh.

Link: https://lkml.kernel.org/r/20240514125254.142203-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20240514125254.142203-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:53 -07:00
Shakeel Butt
462966dc7d mm: vmscan: reset sc->priority on retry
The commit 6be5e186fd65 ("mm: vmscan: restore incremental cgroup
iteration") added a retry reclaim heuristic to iterate all the cgroups
before returning an unsuccessful reclaim but missed to reset the
sc->priority.  Let's fix it.

Link: https://lkml.kernel.org/r/20240529154911.3008025-1-shakeel.butt@linux.dev
Fixes: 6be5e186fd65 ("mm: vmscan: restore incremental cgroup iteration")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by: syzbot+17416257cb95200cba44@syzkaller.appspotmail.com
Tested-by: syzbot+17416257cb95200cba44@syzkaller.appspotmail.com
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:53 -07:00
Johannes Weiner
b82b530740 mm: vmscan: restore incremental cgroup iteration
Currently, reclaim always walks the entire cgroup tree in order to ensure
fairness between groups.  While overreclaim is limited in shrink_lruvec(),
many of our systems have a sizable number of active groups, and an even
bigger number of idle cgroups with cache left behind by previous jobs; the
mere act of walking all these cgroups can impose significant latency on
direct reclaimers.

In the past, we've used a save-and-restore iterator that enabled
incremental tree walks over multiple reclaim invocations.  This ensured
fairness, while keeping the work of individual reclaimers small.

However, in edge cases with a lot of reclaim concurrency, individual
reclaimers would sometimes not see enough of the cgroup tree to make
forward progress and (prematurely) declare OOM.  Consequently we switched
to comprehensive walks in 1ba6fc9af35b ("mm: vmscan: do not share cgroup
iteration between reclaimers").

To address the latency problem without bringing back the premature OOM
issue, reinstate the shared iteration, but with a restart condition to do
the full walk in the OOM case - similar to what we do for memory.low
enforcement and active page protection.

In the worst case, we do one more full tree walk before declaring
OOM. But the vast majority of direct reclaim scans can then finish
much quicker, while fairness across the tree is maintained:

- Before this patch, we observed that direct reclaim always takes more
  than 100us and most direct reclaim time is spent in reclaim cycles
  lasting between 1ms and 1 second. Almost 40% of direct reclaim time
  was spent on reclaim cycles exceeding 100ms.

- With this patch, almost all page reclaim cycles last less than 10ms,
  and a good amount of direct page reclaim finishes in under 100us. No
  page reclaim cycles lasting over 100ms were observed anymore.

The shared iterator state is maintaned inside the target cgroup, so
fair and incremental walks are performed during both global reclaim
and cgroup limit reclaim of complex subtrees.

Link: https://lkml.kernel.org/r/20240514202641.2821494-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Rik van Riel <riel@surriel.com>
Reported-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Facebook Kernel Team <kernel-team@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:53 -07:00
Kefeng Wang
6f775463d0 mm: shmem: use folio_alloc_mpol() in shmem_alloc_folio()
Let's change shmem_alloc_folio() to take a order and use
folio_alloc_mpol() helper, then directly use it for normal or large folio
to cleanup code.

Link: https://lkml.kernel.org/r/20240515070709.78529-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:53 -07:00
Kefeng Wang
1d9cb7852b mm: mempolicy: use folio_alloc_mpol() in alloc_migration_target_by_mpol()
Convert to use folio_alloc_mpol() to make vma_alloc_folio_noprof() to use
folio throughout.

Link: https://lkml.kernel.org/r/20240515070709.78529-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:53 -07:00
Kefeng Wang
3174d70cf6 mm: mempolicy: use folio_alloc_mpol_noprof() in vma_alloc_folio_noprof()
Convert to use folio_alloc_mpol_noprof() to make vma_alloc_folio_noprof()
to use folio throughout.

Link: https://lkml.kernel.org/r/20240515070709.78529-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:52 -07:00
Kefeng Wang
a19621ed4e mm: add folio_alloc_mpol()
Patch series "mm: convert to folio_alloc_mpol()".


This patch (of 4):

This adds a new folio_alloc_mpol() like folio_alloc() but allocate folio
according to NUMA mempolicy.

Link: https://lkml.kernel.org/r/20240515070709.78529-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240515070709.78529-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:52 -07:00
Oscar Salvador
6584a14a37 mm/hugetlb: drop node_alloc_noretry from alloc_fresh_hugetlb_folio
Since commit d67e32f26713 ("hugetlb: restructure pool allocations"), the
parameter node_alloc_noretry from alloc_fresh_hugetlb_folio() is not used,
so drop it.

Link: https://lkml.kernel.org/r/20240516081035.5651-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:52 -07:00
Illia Ostapyshyn
0ba5e806e1 mm/vmscan: update stale references to shrink_page_list
Commit 49fd9b6df54e ("mm/vmscan: fix a lot of comments") renamed
shrink_page_list() to shrink_folio_list().  Fix up the remaining
references to the old name in comments and documentation.

Link: https://lkml.kernel.org/r/20240517091348.1185566-1-illia@yshyn.com
Signed-off-by: Illia Ostapyshyn <illia@yshyn.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:52 -07:00
Thomas Weißschuh
525c303049 mm/hugetlb: constify ctl_table arguments of utility functions
The sysctl core is preparing to only expose instances of struct ctl_table
as "const".  This will also affect the ctl_table argument of sysctl
handlers.

As the function prototype of all sysctl handlers throughout the tree
needs to stay consistent that change will be done in one commit.

To reduce the size of that final commit, switch utility functions which
are not bound by "typedef proc_handler" to "const struct ctl_table".

No functional change.

Link: https://lkml.kernel.org/r/20240518-sysctl-const-handler-hugetlb-v1-1-47e34e2871b2@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Joel Granados <j.granados@samsung.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 19:29:52 -07:00
Jan Kara
385d838df2 mm: avoid overflows in dirty throttling logic
The dirty throttling logic is interspersed with assumptions that dirty
limits in PAGE_SIZE units fit into 32-bit (so that various multiplications
fit into 64-bits).  If limits end up being larger, we will hit overflows,
possible divisions by 0 etc.  Fix these problems by never allowing so
large dirty limits as they have dubious practical value anyway.  For
dirty_bytes / dirty_background_bytes interfaces we can just refuse to set
so large limits.  For dirty_ratio / dirty_background_ratio it isn't so
simple as the dirty limit is computed from the amount of available memory
which can change due to memory hotplug etc.  So when converting dirty
limits from ratios to numbers of pages, we just don't allow the result to
exceed UINT_MAX.

This is root-only triggerable problem which occurs when the operator
sets dirty limits to >16 TB.

Link: https://lkml.kernel.org/r/20240621144246.11148-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-By: Zach O'Keefe <zokeefe@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 12:29:24 -07:00
Jan Kara
30139c7020 Revert "mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again"
Patch series "mm: Avoid possible overflows in dirty throttling".

Dirty throttling logic assumes dirty limits in page units fit into
32-bits.  This patch series makes sure this is true (see patch 2/2 for
more details).


This patch (of 2):

This reverts commit 9319b647902cbd5cc884ac08a8a6d54ce111fc78.

The commit is broken in several ways.  Firstly, the removed (u64) cast
from the multiplication will introduce a multiplication overflow on 32-bit
archs if wb_thresh * bg_thresh >= 1<<32 (which is actually common - the
default settings with 4GB of RAM will trigger this).  Secondly, the
div64_u64() is unnecessarily expensive on 32-bit archs.  We have
div64_ul() in case we want to be safe & cheap.  Thirdly, if dirty
thresholds are larger than 1<<32 pages, then dirty balancing is going to
blow up in many other spectacular ways anyway so trying to fix one
possible overflow is just moot.

Link: https://lkml.kernel.org/r/20240621144017.30993-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20240621144246.11148-1-jack@suse.cz
Fixes: 9319b647902c ("mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-By: Zach O'Keefe <zokeefe@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-03 12:29:24 -07:00
Andrew Bresticker
ab1ffc86cb mm/memory: don't require head page for do_set_pmd()
The requirement that the head page be passed to do_set_pmd() was added in
commit ef37b2ea08ac ("mm/memory: page_add_file_rmap() ->
folio_add_file_rmap_[pte|pmd]()") and prevents pmd-mapping in the
finish_fault() and filemap_map_pages() paths if the page to be inserted is
anything but the head page for an otherwise suitable vma and pmd-sized
page.

Matthew said:

: We're going to stop using PMDs to map large folios unless the fault is
: within the first 4KiB of the PMD.  No idea how many workloads that
: affects, but it only needs to be backported as far as v6.8, so we may
: as well backport it.

Link: https://lkml.kernel.org/r/20240611153216.2794513-1-abrestic@rivosinc.com
Fixes: ef37b2ea08ac ("mm/memory: page_add_file_rmap() -> folio_add_file_rmap_[pte|pmd]()")
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:11 -07:00
yangge
bf14ed81f5 mm/page_alloc: Separate THP PCP into movable and non-movable categories
Since commit 5d0a661d808f ("mm/page_alloc: use only one PCP list for
THP-sized allocations") no longer differentiates the migration type of
pages in THP-sized PCP list, it's possible that non-movable allocation
requests may get a CMA page from the list, in some cases, it's not
acceptable.

If a large number of CMA memory are configured in system (for example, the
CMA memory accounts for 50% of the system memory), starting a virtual
machine with device passthrough will get stuck.  During starting the
virtual machine, it will call pin_user_pages_remote(..., FOLL_LONGTERM,
...) to pin memory.  Normally if a page is present and in CMA area,
pin_user_pages_remote() will migrate the page from CMA area to non-CMA
area because of FOLL_LONGTERM flag.  But if non-movable allocation
requests return CMA memory, migrate_longterm_unpinnable_pages() will
migrate a CMA page to another CMA page, which will fail to pass the check
in check_and_migrate_movable_pages() and cause migration endless.

Call trace:
pin_user_pages_remote
--__gup_longterm_locked // endless loops in this function
----_get_user_pages_locked
----check_and_migrate_movable_pages
------migrate_longterm_unpinnable_pages
--------alloc_migration_target

This problem will also have a negative impact on CMA itself.  For example,
when CMA is borrowed by THP, and we need to reclaim it through cma_alloc()
or dma_alloc_coherent(), we must move those pages out to ensure CMA's
users can retrieve that contigous memory.  Currently, CMA's memory is
occupied by non-movable pages, meaning we can't relocate them.  As a
result, cma_alloc() is more likely to fail.

To fix the problem above, we add one PCP list for THP, which will not
introduce a new cacheline for struct per_cpu_pages.  THP will have 2 PCP
lists, one PCP list is used by MOVABLE allocation, and the other PCP list
is used by UNMOVABLE allocation.  MOVABLE allocation contains GPF_MOVABLE,
and UNMOVABLE allocation contains GFP_UNMOVABLE and GFP_RECLAIMABLE.

Link: https://lkml.kernel.org/r/1718845190-4456-1-git-send-email-yangge1116@126.com
Fixes: 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations")
Signed-off-by: yangge <yangge1116@126.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:11 -07:00
Zi Yan
c640825070 mm/migrate: make migrate_pages_batch() stats consistent
As Ying pointed out in [1], stats->nr_thp_failed needs to be updated to
avoid stats inconsistency between MIGRATE_SYNC and MIGRATE_ASYNC when
calling migrate_pages_batch().

Because if not, when migrate_pages_batch() is called via
migrate_pages(MIGRATE_ASYNC), nr_thp_failed will not be increased and when
migrate_pages_batch() is called via migrate_pages(MIGRATE_SYNC*),
nr_thp_failed will be increase in migrate_pages_sync() by
stats->nr_thp_failed += astats.nr_thp_split.

[1] https://lore.kernel.org/linux-mm/87msnq7key.fsf@yhuang6-desk2.ccr.corp.intel.com/

Link: https://lkml.kernel.org/r/20240620012712.19804-1-zi.yan@sent.com
Link: https://lkml.kernel.org/r/20240618134151.29214-1-zi.yan@sent.com
Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:10 -07:00
Andrey Konovalov
1c61990d37 kasan: fix bad call to unpoison_slab_object
Commit 29d7355a9d05 ("kasan: save alloc stack traces for mempool") messed
up one of the calls to unpoison_slab_object: the last two arguments are
supposed to be GFP flags and whether to init the object memory.

Fix the call.

Without this fix, __kasan_mempool_unpoison_object provides the object's
size as GFP flags to unpoison_slab_object, which can cause LOCKDEP reports
(and probably other issues).

Link: https://lkml.kernel.org/r/20240614143238.60323-1-andrey.konovalov@linux.dev
Fixes: 29d7355a9d05 ("kasan: save alloc stack traces for mempool")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: Brad Spengler <spender@grsecurity.net>
Acked-by: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:09 -07:00
Suren Baghdasaryan
34a023dc88 mm: handle profiling for fake memory allocations during compaction
During compaction isolated free pages are marked allocated so that they
can be split and/or freed.  For that, post_alloc_hook() is used inside
split_map_pages() and release_free_list().  split_map_pages() marks free
pages allocated, splits the pages and then lets
alloc_contig_range_noprof() free those pages.  release_free_list() marks
free pages and immediately frees them.  This usage of post_alloc_hook()
affect memory allocation profiling because these functions might not be
called from an instrumented allocator, therefore current->alloc_tag is
NULL and when debugging is enabled (CONFIG_MEM_ALLOC_PROFILING_DEBUG=y)
that causes warnings.  To avoid that, wrap such post_alloc_hook() calls
into an instrumented function which acts as an allocator which will be
charged for these fake allocations.  Note that these allocations are very
short lived until they are freed, therefore the associated counters should
usually read 0.

Link: https://lkml.kernel.org/r/20240614230504.3849136-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:09 -07:00
Suren Baghdasaryan
b4601d096a mm/slab: fix 'variable obj_exts set but not used' warning
slab_post_alloc_hook() uses prepare_slab_obj_exts_hook() to obtain
slabobj_ext object.  Currently the only user of slabobj_ext object in this
path is memory allocation profiling, therefore when it's not enabled this
object is not needed.  This also generates a warning when compiling with
CONFIG_MEM_ALLOC_PROFILING=n.  Move the code under this configuration to
fix the warning.  If more slabobj_ext users appear in the future, the code
will have to be changed back to call prepare_slab_obj_exts_hook().

Link: https://lkml.kernel.org/r/20240614225951.3845577-1-surenb@google.com
Fixes: 4b8736964640 ("mm/slab: add allocation accounting into slab allocation and free paths")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406150444.F6neSaiy-lkp@intel.com/
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:09 -07:00
Jeff Xu
399ab86ea5 /proc/pid/smaps: add mseal info for vma
Add sl in /proc/pid/smaps to indicate vma is sealed

Link: https://lkml.kernel.org/r/20240614232014.806352-2-jeffxu@google.com
Fixes: 8be7258aad44 ("mseal: add mseal syscall")
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Stephen Röttger <sroettger@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:09 -07:00
Zhaoyang Huang
8c61291fd8 mm: fix incorrect vbq reference in purge_fragmented_block
xa_for_each() in _vm_unmap_aliases() loops through all vbs.  However,
since commit 062eacf57ad9 ("mm: vmalloc: remove a global vmap_blocks
xarray") the vb from xarray may not be on the corresponding CPU
vmap_block_queue.  Consequently, purge_fragmented_block() might use the
wrong vbq->lock to protect the free list, leading to vbq->free breakage.

Incorrect lock protection can exhaust all vmalloc space as follows:
CPU0                                            CPU1
+--------------------------------------------+
|    +--------------------+     +-----+      |
+--> |                    |---->|     |------+
     | CPU1:vbq free_list |     | vb1 |
+--- |                    |<----|     |<-----+
|    +--------------------+     +-----+      |
+--------------------------------------------+

_vm_unmap_aliases()                             vb_alloc()
                                                new_vmap_block()
xa_for_each(&vbq->vmap_blocks, idx, vb)
--> vb in CPU1:vbq->freelist

purge_fragmented_block(vb)
spin_lock(&vbq->lock)                           spin_lock(&vbq->lock)
--> use CPU0:vbq->lock                          --> use CPU1:vbq->lock

list_del_rcu(&vb->free_list)                    list_add_tail_rcu(&vb->free_list, &vbq->free)
    __list_del(vb->prev, vb->next)
        next->prev = prev
    +--------------------+
    |                    |
    | CPU1:vbq free_list |
+---|                    |<--+
|   +--------------------+   |
+----------------------------+
                                                __list_add(new, head->prev, head)
+--------------------------------------------+
|    +--------------------+     +-----+      |
+--> |                    |---->|     |------+
     | CPU1:vbq free_list |     | vb2 |
+--- |                    |<----|     |<-----+
|    +--------------------+     +-----+      |
+--------------------------------------------+

        prev->next = next
+--------------------------------------------+
|----------------------------+               |
|    +--------------------+  |  +-----+      |
+--> |                    |--+  |     |------+
     | CPU1:vbq free_list |     | vb2 |
+--- |                    |<----|     |<-----+
|    +--------------------+     +-----+      |
+--------------------------------------------+
Here’s a list breakdown. All vbs, which were to be added to
‘prev’, cannot be used by list_for_each_entry_rcu(vb, &vbq->free,
free_list) in vb_alloc(). Thus, vmalloc space is exhausted.

This issue affects both erofs and f2fs, the stacktrace is as follows:
erofs:
[<ffffffd4ffb93ad4>] __switch_to+0x174
[<ffffffd4ffb942f0>] __schedule+0x624
[<ffffffd4ffb946f4>] schedule+0x7c
[<ffffffd4ffb947cc>] schedule_preempt_disabled+0x24
[<ffffffd4ffb962ec>] __mutex_lock+0x374
[<ffffffd4ffb95998>] __mutex_lock_slowpath+0x14
[<ffffffd4ffb95954>] mutex_lock+0x24
[<ffffffd4fef2900c>] reclaim_and_purge_vmap_areas+0x44
[<ffffffd4fef25908>] alloc_vmap_area+0x2e0
[<ffffffd4fef24ea0>] vm_map_ram+0x1b0
[<ffffffd4ff1b46f4>] z_erofs_lz4_decompress+0x278
[<ffffffd4ff1b8ac4>] z_erofs_decompress_queue+0x650
[<ffffffd4ff1b8328>] z_erofs_runqueue+0x7f4
[<ffffffd4ff1b66a8>] z_erofs_read_folio+0x104
[<ffffffd4feeb6fec>] filemap_read_folio+0x6c
[<ffffffd4feeb68c4>] filemap_fault+0x300
[<ffffffd4fef0ecac>] __do_fault+0xc8
[<ffffffd4fef0c908>] handle_mm_fault+0xb38
[<ffffffd4ffb9f008>] do_page_fault+0x288
[<ffffffd4ffb9ed64>] do_translation_fault[jt]+0x40
[<ffffffd4fec39c78>] do_mem_abort+0x58
[<ffffffd4ffb8c3e4>] el0_ia+0x70
[<ffffffd4ffb8c260>] el0t_64_sync_handler[jt]+0xb0
[<ffffffd4fec11588>] ret_to_user[jt]+0x0

f2fs:
[<ffffffd4ffb93ad4>] __switch_to+0x174
[<ffffffd4ffb942f0>] __schedule+0x624
[<ffffffd4ffb946f4>] schedule+0x7c
[<ffffffd4ffb947cc>] schedule_preempt_disabled+0x24
[<ffffffd4ffb962ec>] __mutex_lock+0x374
[<ffffffd4ffb95998>] __mutex_lock_slowpath+0x14
[<ffffffd4ffb95954>] mutex_lock+0x24
[<ffffffd4fef2900c>] reclaim_and_purge_vmap_areas+0x44
[<ffffffd4fef25908>] alloc_vmap_area+0x2e0
[<ffffffd4fef24ea0>] vm_map_ram+0x1b0
[<ffffffd4ff1a3b60>] f2fs_prepare_decomp_mem+0x144
[<ffffffd4ff1a6c24>] f2fs_alloc_dic+0x264
[<ffffffd4ff175468>] f2fs_read_multi_pages+0x428
[<ffffffd4ff17b46c>] f2fs_mpage_readpages+0x314
[<ffffffd4ff1785c4>] f2fs_readahead+0x50
[<ffffffd4feec3384>] read_pages+0x80
[<ffffffd4feec32c0>] page_cache_ra_unbounded+0x1a0
[<ffffffd4feec39e8>] page_cache_ra_order+0x274
[<ffffffd4feeb6cec>] do_sync_mmap_readahead+0x11c
[<ffffffd4feeb6764>] filemap_fault+0x1a0
[<ffffffd4ff1423bc>] f2fs_filemap_fault+0x28
[<ffffffd4fef0ecac>] __do_fault+0xc8
[<ffffffd4fef0c908>] handle_mm_fault+0xb38
[<ffffffd4ffb9f008>] do_page_fault+0x288
[<ffffffd4ffb9ed64>] do_translation_fault[jt]+0x40
[<ffffffd4fec39c78>] do_mem_abort+0x58
[<ffffffd4ffb8c3e4>] el0_ia+0x70
[<ffffffd4ffb8c260>] el0t_64_sync_handler[jt]+0xb0
[<ffffffd4fec11588>] ret_to_user[jt]+0x0

To fix this, introducee cpu within vmap_block to record which this vb
belongs to.

Link: https://lkml.kernel.org/r/20240614021352.1822225-1-zhaoyang.huang@unisoc.com
Link: https://lkml.kernel.org/r/20240607023116.1720640-1-zhaoyang.huang@unisoc.com
Fixes: fc1e0d980037 ("mm/vmalloc: prevent stale TLBs in fully utilized blocks")
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Suggested-by: Hailong.Liu <hailong.liu@oppo.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-06-24 20:52:08 -07:00