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[ Upstream commit 35e41024c4c2b02ef8207f61b9004f6956cf037b ]
When numa balancing is enabled with demotion, vmscan will call
migrate_pages when shrinking LRUs. migrate_pages will decrement the
the node's isolated page count, leading to an imbalanced count when
invoked from (MG)LRU code.
The result is dmesg output like such:
$ cat /proc/sys/vm/stat_refresh
[77383.088417] vmstat_refresh: nr_isolated_anon -103212
[77383.088417] vmstat_refresh: nr_isolated_file -899642
This negative value may impact compaction and reclaim throttling.
The following path produces the decrement:
shrink_folio_list
demote_folio_list
migrate_pages
migrate_pages_batch
migrate_folio_move
migrate_folio_done
mod_node_page_state(-ve) <- decrement
This path happens for SUCCESSFUL migrations, not failures. Typically
callers to migrate_pages are required to handle putback/accounting for
failures, but this is already handled in the shrink code.
When accounting for migrations, instead do not decrement the count when
the migration reason is MR_DEMOTION. As of v6.11, this demotion logic
is the only source of MR_DEMOTION.
Link: https://lkml.kernel.org/r/20241025141724.17927-1-gourry@gourry.net
Fixes: 26aa2d199d6f ("mm/migrate: demote pages during reclaim")
Signed-off-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 8001070cfbec5cd4ea00b8b48ea51df91122f265 upstream.
I found a report from syzbot [1]
This report shows that the value can be changed, but in reality, the
value of __folio_set_movable() cannot be changed because it holds the
folio refcount.
Therefore, it is appropriate to add an annotate to make KCSAN
ignore that data-race.
[1]
==================================================================
BUG: KCSAN: data-race in __filemap_remove_folio / migrate_pages_batch
write to 0xffffea0004b81dd8 of 8 bytes by task 6348 on cpu 0:
page_cache_delete mm/filemap.c:153 [inline]
__filemap_remove_folio+0x1ac/0x2c0 mm/filemap.c:233
filemap_remove_folio+0x6b/0x1f0 mm/filemap.c:265
truncate_inode_folio+0x42/0x50 mm/truncate.c:178
shmem_undo_range+0x25b/0xa70 mm/shmem.c:1028
shmem_truncate_range mm/shmem.c:1144 [inline]
shmem_evict_inode+0x14d/0x530 mm/shmem.c:1272
evict+0x2f0/0x580 fs/inode.c:731
iput_final fs/inode.c:1883 [inline]
iput+0x42a/0x5b0 fs/inode.c:1909
dentry_unlink_inode+0x24f/0x260 fs/dcache.c:412
__dentry_kill+0x18b/0x4c0 fs/dcache.c:615
dput+0x5c/0xd0 fs/dcache.c:857
__fput+0x3fb/0x6d0 fs/file_table.c:439
____fput+0x1c/0x30 fs/file_table.c:459
task_work_run+0x13a/0x1a0 kernel/task_work.c:228
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
read to 0xffffea0004b81dd8 of 8 bytes by task 6342 on cpu 1:
__folio_test_movable include/linux/page-flags.h:699 [inline]
migrate_folio_unmap mm/migrate.c:1199 [inline]
migrate_pages_batch+0x24c/0x1940 mm/migrate.c:1797
migrate_pages_sync mm/migrate.c:1963 [inline]
migrate_pages+0xff1/0x1820 mm/migrate.c:2072
do_mbind mm/mempolicy.c:1390 [inline]
kernel_mbind mm/mempolicy.c:1533 [inline]
__do_sys_mbind mm/mempolicy.c:1607 [inline]
__se_sys_mbind+0xf76/0x1160 mm/mempolicy.c:1603
__x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1603
x64_sys_call+0x2b4d/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:238
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
value changed: 0xffff888127601078 -> 0x0000000000000000
Link: https://lkml.kernel.org/r/20240924130053.107490-1-aha310510@gmail.com
Fixes: 7e2a5e5ab217 ("mm: migrate: use __folio_test_movable()")
Signed-off-by: Jeongjun Park <aha310510@gmail.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently, migrate_pages_batch() can lock multiple locked folios with an
arbitrary order. Although folio_trylock() is used to avoid deadlock as
commit 2ef7dbb26990 ("migrate_pages: try migrate in batch asynchronously
firstly") mentioned, it seems try_split_folio() is still missing.
It was found by compaction stress test when I explicitly enable EROFS
compressed files to use large folios, which case I cannot reproduce with
the same workload if large folio support is off (current mainline).
Typically, filesystem reads (with locked file-backed folios) could use
another bdev/meta inode to load some other I/Os (e.g. inode extent
metadata or caching compressed data), so the locking order will be:
file-backed folios (A)
bdev/meta folios (B)
The following calltrace shows the deadlock:
Thread 1 takes (B) lock and tries to take folio (A) lock
Thread 2 takes (A) lock and tries to take folio (B) lock
[Thread 1]
INFO: task stress:1824 blocked for more than 30 seconds.
Tainted: G OE 6.10.0-rc7+ #6
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:stress state:D stack:0 pid:1824 tgid:1824 ppid:1822 flags:0x0000000c
Call trace:
__switch_to+0xec/0x138
__schedule+0x43c/0xcb0
schedule+0x54/0x198
io_schedule+0x44/0x70
folio_wait_bit_common+0x184/0x3f8
<-- folio mapping ffff00036d69cb18 index 996 (**)
__folio_lock+0x24/0x38
migrate_pages_batch+0x77c/0xea0 // try_split_folio (mm/migrate.c:1486:2)
// migrate_pages_batch (mm/migrate.c:1734:16)
<--- LIST_HEAD(unmap_folios) has
..
folio mapping 0xffff0000d184f1d8 index 1711; (*)
folio mapping 0xffff0000d184f1d8 index 1712;
..
migrate_pages+0xb28/0xe90
compact_zone+0xa08/0x10f0
compact_node+0x9c/0x180
sysctl_compaction_handler+0x8c/0x118
proc_sys_call_handler+0x1a8/0x280
proc_sys_write+0x1c/0x30
vfs_write+0x240/0x380
ksys_write+0x78/0x118
__arm64_sys_write+0x24/0x38
invoke_syscall+0x78/0x108
el0_svc_common.constprop.0+0x48/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x3c/0x148
el0t_64_sync_handler+0x100/0x130
el0t_64_sync+0x190/0x198
[Thread 2]
INFO: task stress:1825 blocked for more than 30 seconds.
Tainted: G OE 6.10.0-rc7+ #6
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:stress state:D stack:0 pid:1825 tgid:1825 ppid:1822 flags:0x0000000c
Call trace:
__switch_to+0xec/0x138
__schedule+0x43c/0xcb0
schedule+0x54/0x198
io_schedule+0x44/0x70
folio_wait_bit_common+0x184/0x3f8
<-- folio = 0xfffffdffc6b503c0 (mapping == 0xffff0000d184f1d8 index == 1711) (*)
__folio_lock+0x24/0x38
z_erofs_runqueue+0x384/0x9c0 [erofs]
z_erofs_readahead+0x21c/0x350 [erofs] <-- folio mapping 0xffff00036d69cb18 range from [992, 1024] (**)
read_pages+0x74/0x328
page_cache_ra_order+0x26c/0x348
ondemand_readahead+0x1c0/0x3a0
page_cache_sync_ra+0x9c/0xc0
filemap_get_pages+0xc4/0x708
filemap_read+0x104/0x3a8
generic_file_read_iter+0x4c/0x150
vfs_read+0x27c/0x330
ksys_pread64+0x84/0xd0
__arm64_sys_pread64+0x28/0x40
invoke_syscall+0x78/0x108
el0_svc_common.constprop.0+0x48/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x3c/0x148
el0t_64_sync_handler+0x100/0x130
el0t_64_sync+0x190/0x198
Link: https://lkml.kernel.org/r/20240729021306.398286-1-hsiangkao@linux.alibaba.com
Fixes: 5dfab109d519 ("migrate_pages: batch _unmap and _move")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- In the series "mm: Avoid possible overflows in dirty throttling" Jan
Kara addresses a couple of issues in the writeback throttling code.
These fixes are also targetted at -stable kernels.
- Ryusuke Konishi's series "nilfs2: fix potential issues related to
reserved inodes" does that. This should actually be in the
mm-nonmm-stable tree, along with the many other nilfs2 patches. My
bad.
- More folio conversions from Kefeng Wang in the series "mm: convert to
folio_alloc_mpol()"
- Kemeng Shi has sent some cleanups to the writeback code in the series
"Add helper functions to remove repeated code and improve readability
of cgroup writeback"
- Kairui Song has made the swap code a little smaller and a little
faster in the series "mm/swap: clean up and optimize swap cache
index".
- In the series "mm/memory: cleanly support zeropage in
vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
Hildenbrand has reworked the rather sketchy handling of the use of
the zeropage in MAP_SHARED mappings. I don't see any runtime effects
here - more a cleanup/understandability/maintainablity thing.
- Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling
of higher addresses, for aarch64. The (poorly named) series is
"Restructure va_high_addr_switch".
- The core TLB handling code gets some cleanups and possible slight
optimizations in Bang Li's series "Add update_mmu_tlb_range() to
simplify code".
- Jane Chu has improved the handling of our
fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in
the series "Enhance soft hwpoison handling and injection".
- Jeff Johnson has sent a billion patches everywhere to add
MODULE_DESCRIPTION() to everything. Some landed in this pull.
- In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang
has simplified migration's use of hardware-offload memory copying.
- Yosry Ahmed performs more folio API conversions in his series "mm:
zswap: trivial folio conversions".
- In the series "large folios swap-in: handle refault cases first",
Chuanhua Han inches us forward in the handling of large pages in the
swap code. This is a cleanup and optimization, working toward the end
objective of full support of large folio swapin/out.
- In the series "mm,swap: cleanup VMA based swap readahead window
calculation", Huang Ying has contributed some cleanups and a possible
fixlet to his VMA based swap readahead code.
- In the series "add mTHP support for anonymous shmem" Baolin Wang has
taught anonymous shmem mappings to use multisize THP. By default this
is a no-op - users must opt in vis sysfs controls. Dramatic
improvements in pagefault latency are realized.
- David Hildenbrand has some cleanups to our remaining use of
page_mapcount() in the series "fs/proc: move page_mapcount() to
fs/proc/internal.h".
- David also has some highmem accounting cleanups in the series
"mm/highmem: don't track highmem pages manually".
- Build-time fixes and cleanups from John Hubbard in the series
"cleanups, fixes, and progress towards avoiding "make headers"".
- Cleanups and consolidation of the core pagemap handling from Barry
Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
and utilize them".
- Lance Yang's series "Reclaim lazyfree THP without splitting" has
reduced the latency of the reclaim of pmd-mapped THPs under fairly
common circumstances. A 10x speedup is seen in a microbenchmark.
It does this by punting to aother CPU but I guess that's a win unless
all CPUs are pegged.
- hugetlb_cgroup cleanups from Xiu Jianfeng in the series
"mm/hugetlb_cgroup: rework on cftypes".
- Miaohe Lin's series "Some cleanups for memory-failure" does just that
thing.
- Someone other than SeongJae has developed a DAMON feature in Honggyu
Kim's series "DAMON based tiered memory management for CXL memory".
This adds DAMON features which may be used to help determine the
efficiency of our placement of CXL/PCIe attached DRAM.
- DAMON user API centralization and simplificatio work in SeongJae
Park's series "mm/damon: introduce DAMON parameters online commit
function".
- In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
David Hildenbrand does some maintenance work on zsmalloc - partially
modernizing its use of pageframe fields.
- Kefeng Wang provides more folio conversions in the series "mm: remove
page_maybe_dma_pinned() and page_mkclean()".
- More cleanup from David Hildenbrand, this time in the series
"mm/memory_hotplug: use PageOffline() instead of PageReserved() for
!ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
pages" and permits the removal of some virtio-mem hacks.
- Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
__folio_add_anon_rmap()" is a cleanup to the anon folio handling in
preparation for mTHP (multisize THP) swapin.
- Kefeng Wang's series "mm: improve clear and copy user folio"
implements more folio conversions, this time in the area of large
folio userspace copying.
- The series "Docs/mm/damon/maintaier-profile: document a mailing tool
and community meetup series" tells people how to get better involved
with other DAMON developers. From SeongJae Park.
- A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
that.
- David Hildenbrand sends along more cleanups, this time against the
migration code. The series is "mm/migrate: move NUMA hinting fault
folio isolation + checks under PTL".
- Jan Kara has found quite a lot of strangenesses and minor errors in
the readahead code. He addresses this in the series "mm: Fix various
readahead quirks".
- SeongJae Park's series "selftests/damon: test DAMOS tried regions and
{min,max}_nr_regions" adds features and addresses errors in DAMON's
self testing code.
- Gavin Shan has found a userspace-triggerable WARN in the pagecache
code. The series "mm/filemap: Limit page cache size to that supported
by xarray" addresses this. The series is marked cc:stable.
- Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
and cleanup" cleans up and slightly optimizes KSM.
- Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
code motion. The series (which also makes the memcg-v1 code
Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put
under config option" and "mm: memcg: put cgroup v1-specific memcg
data under CONFIG_MEMCG_V1"
- Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
adds an additional feature to this cgroup-v2 control file.
- The series "Userspace controls soft-offline pages" from Jiaqi Yan
permits userspace to stop the kernel's automatic treatment of
excessive correctable memory errors. In order to permit userspace to
monitor and handle this situation.
- Kefeng Wang's series "mm: migrate: support poison recover from
migrate folio" teaches the kernel to appropriately handle migration
from poisoned source folios rather than simply panicing.
- SeongJae Park's series "Docs/damon: minor fixups and improvements"
does those things.
- In the series "mm/zsmalloc: change back to per-size_class lock"
Chengming Zhou improves zsmalloc's scalability and memory
utilization.
- Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
pinning memfd folios" makes the GUP code use FOLL_PIN rather than
bare refcount increments. So these paes can first be moved aside if
they reside in the movable zone or a CMA block.
- Andrii Nakryiko has added a binary ioctl()-based API to
/proc/pid/maps for much faster reading of vma information. The series
is "query VMAs from /proc/<pid>/maps".
- In the series "mm: introduce per-order mTHP split counters" Lance
Yang improves the kernel's presentation of developer information
related to multisize THP splitting.
- Michael Ellerman has developed the series "Reimplement huge pages
without hugepd on powerpc (8xx, e500, book3s/64)". This permits
userspace to use all available huge page sizes.
- In the series "revert unconditional slab and page allocator fault
injection calls" Vlastimil Babka removes a performance-affecting and
not very useful feature from slab fault injection.
* tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits)
mm/mglru: fix ineffective protection calculation
mm/zswap: fix a white space issue
mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio
mm/hugetlb: fix possible recursive locking detected warning
mm/gup: clear the LRU flag of a page before adding to LRU batch
mm/numa_balancing: teach mpol_to_str about the balancing mode
mm: memcg1: convert charge move flags to unsigned long long
alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting
lib: reuse page_ext_data() to obtain codetag_ref
lib: add missing newline character in the warning message
mm/mglru: fix overshooting shrinker memory
mm/mglru: fix div-by-zero in vmpressure_calc_level()
mm/kmemleak: replace strncpy() with strscpy()
mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
mm: ignore data-race in __swap_writepage
hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr
mm: shmem: rename mTHP shmem counters
mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async()
mm/migrate: putback split folios when numa hint migration fails
...
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Pull kvm updates from Paolo Bonzini:
"ARM:
- Initial infrastructure for shadow stage-2 MMUs, as part of nested
virtualization enablement
- Support for userspace changes to the guest CTR_EL0 value, enabling
(in part) migration of VMs between heterogenous hardware
- Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1
of the protocol
- FPSIMD/SVE support for nested, including merged trap configuration
and exception routing
- New command-line parameter to control the WFx trap behavior under
KVM
- Introduce kCFI hardening in the EL2 hypervisor
- Fixes + cleanups for handling presence/absence of FEAT_TCRX
- Miscellaneous fixes + documentation updates
LoongArch:
- Add paravirt steal time support
- Add support for KVM_DIRTY_LOG_INITIALLY_SET
- Add perf kvm-stat support for loongarch
RISC-V:
- Redirect AMO load/store access fault traps to guest
- perf kvm stat support
- Use guest files for IMSIC virtualization, when available
s390:
- Assortment of tiny fixes which are not time critical
x86:
- Fixes for Xen emulation
- Add a global struct to consolidate tracking of host values, e.g.
EFER
- Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the
effective APIC bus frequency, because TDX
- Print the name of the APICv/AVIC inhibits in the relevant
tracepoint
- Clean up KVM's handling of vendor specific emulation to
consistently act on "compatible with Intel/AMD", versus checking
for a specific vendor
- Drop MTRR virtualization, and instead always honor guest PAT on
CPUs that support self-snoop
- Update to the newfangled Intel CPU FMS infrastructure
- Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as
it reads '0' and writes from userspace are ignored
- Misc cleanups
x86 - MMU:
- Small cleanups, renames and refactoring extracted from the upcoming
Intel TDX support
- Don't allocate kvm_mmu_page.shadowed_translation for shadow pages
that can't hold leafs SPTEs
- Unconditionally drop mmu_lock when allocating TDP MMU page tables
for eager page splitting, to avoid stalling vCPUs when splitting
huge pages
- Bug the VM instead of simply warning if KVM tries to split a SPTE
that is non-present or not-huge. KVM is guaranteed to end up in a
broken state because the callers fully expect a valid SPTE, it's
all but dangerous to let more MMU changes happen afterwards
x86 - AMD:
- Make per-CPU save_area allocations NUMA-aware
- Force sev_es_host_save_area() to be inlined to avoid calling into
an instrumentable function from noinstr code
- Base support for running SEV-SNP guests. API-wise, this includes a
new KVM_X86_SNP_VM type, encrypting/measure the initial image into
guest memory, and finalizing it before launching it. Internally,
there are some gmem/mmu hooks needed to prepare gmem-allocated
pages before mapping them into guest private memory ranges
This includes basic support for attestation guest requests, enough
to say that KVM supports the GHCB 2.0 specification
There is no support yet for loading into the firmware those signing
keys to be used for attestation requests, and therefore no need yet
for the host to provide certificate data for those keys.
To support fetching certificate data from userspace, a new KVM exit
type will be needed to handle fetching the certificate from
userspace.
An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS
exit type to handle this was introduced in v1 of this patchset, but
is still being discussed by community, so for now this patchset
only implements a stub version of SNP Extended Guest Requests that
does not provide certificate data
x86 - Intel:
- Remove an unnecessary EPT TLB flush when enabling hardware
- Fix a series of bugs that cause KVM to fail to detect nested
pending posted interrupts as valid wake eents for a vCPU executing
HLT in L2 (with HLT-exiting disable by L1)
- KVM: x86: Suppress MMIO that is triggered during task switch
emulation
Explicitly suppress userspace emulated MMIO exits that are
triggered when emulating a task switch as KVM doesn't support
userspace MMIO during complex (multi-step) emulation
Silently ignoring the exit request can result in the
WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace
for some other reason prior to purging mmio_needed
See commit 0dc902267cb3 ("KVM: x86: Suppress pending MMIO write
exits if emulator detects exception") for more details on KVM's
limitations with respect to emulated MMIO during complex emulator
flows
Generic:
- Rename the AS_UNMOVABLE flag that was introduced for KVM to
AS_INACCESSIBLE, because the special casing needed by these pages
is not due to just unmovability (and in fact they are only
unmovable because the CPU cannot access them)
- New ioctl to populate the KVM page tables in advance, which is
useful to mitigate KVM page faults during guest boot or after live
migration. The code will also be used by TDX, but (probably) not
through the ioctl
- Enable halt poll shrinking by default, as Intel found it to be a
clear win
- Setup empty IRQ routing when creating a VM to avoid having to
synchronize SRCU when creating a split IRQCHIP on x86
- Rework the sched_in/out() paths to replace kvm_arch_sched_in() with
a flag that arch code can use for hooking both sched_in() and
sched_out()
- Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
truncating a bogus value from userspace, e.g. to help userspace
detect bugs
- Mark a vCPU as preempted if and only if it's scheduled out while in
the KVM_RUN loop, e.g. to avoid marking it preempted and thus
writing guest memory when retrieving guest state during live
migration blackout
Selftests:
- Remove dead code in the memslot modification stress test
- Treat "branch instructions retired" as supported on all AMD Family
17h+ CPUs
- Print the guest pseudo-RNG seed only when it changes, to avoid
spamming the log for tests that create lots of VMs
- Make the PMU counters test less flaky when counting LLC cache
misses by doing CLFLUSH{OPT} in every loop iteration"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits)
crypto: ccp: Add the SNP_VLEK_LOAD command
KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops
KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops
KVM: x86: Replace static_call_cond() with static_call()
KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event
x86/sev: Move sev_guest.h into common SEV header
KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event
KVM: x86: Suppress MMIO that is triggered during task switch emulation
KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro
KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE
KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY
KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory()
KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level
KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault"
KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler
KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory
KVM: Document KVM_PRE_FAULT_MEMORY ioctl
mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE
perf kvm: Add kvm-stat for loongarch64
LoongArch: KVM: Add PV steal time support in guest side
...
|
|
This issue is not from any report yet, but by code observation only.
This is yet another fix besides Hugh's patch [1] but on relevant code
path, where eager split of folio can happen if the folio is already on
deferred list during a folio migration.
Here the issue is NUMA path (migrate_misplaced_folio()) may start to
encounter such folio split now even with MR_NUMA_MISPLACED hint applied.
Then when migrate_pages() didn't migrate all the folios, it's possible the
split small folios be put onto the list instead of the original folio.
Then putting back only the head page won't be enough.
Fix it by putting back all the folios on the list.
[1] https://lore.kernel.org/all/46c948b4-4dd8-6e03-4c7b-ce4e81cfa536@google.com/
[akpm@linux-foundation.org: remove now unused local `nr_pages']
Link: https://lkml.kernel.org/r/20240708215537.2630610-1-peterx@redhat.com
Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now that folio_undo_large_rmappable() is an inline function checking
order and large_rmappable for itself (and __folio_undo_large_rmappable()
is now declared even when CONFIG_TRANASPARENT_HUGEPAGE is off) there is
no need for folio_migrate_mapping() to check large and large_rmappable
first (in the mapping case when it has had to freeze anyway).
Link: https://lkml.kernel.org/r/68feee73-050e-8e98-7a3a-abf78738d92c@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
On powerpc 8xx huge_ptep_get() will need to know whether the given ptep is
a PTE entry or a PMD entry. This cannot be known with the PMD entry
itself because there is no easy way to know it from the content of the
entry.
So huge_ptep_get() will need to know either the size of the page or get
the pmd.
In order to be consistent with huge_ptep_get_and_clear(), give mm and
address to huge_ptep_get().
Link: https://lkml.kernel.org/r/cc00c70dd384298796a4e1b25d6c4eb306d3af85.1719928057.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD
LoongArch KVM changes for v6.11
1. Add ParaVirt steal time support.
2. Add some VM migration enhancement.
3. Add perf kvm-stat support for loongarch.
|
|
The flags AS_UNMOVABLE and AS_INACCESSIBLE were both added just for guest_memfd;
AS_UNMOVABLE is already in existing versions of Linux, while AS_INACCESSIBLE was
acked for inclusion in 6.11.
But really, they are the same thing: only guest_memfd uses them, at least for
now, and guest_memfd pages are unmovable because they should not be
accessed by the CPU.
So merge them into one; use the AS_INACCESSIBLE name which is more comprehensive.
At the same time, this fixes an embarrassing bug where AS_INACCESSIBLE was used
as a bit mask, despite it being just a bit index.
The bug was mostly benign, because AS_INACCESSIBLE's bit representation (1010)
corresponded to setting AS_UNEVICTABLE (which is already set) and AS_ENOSPC
(except no async writes can happen on the guest_memfd). So the AS_INACCESSIBLE
flag simply had no effect.
Fixes: 1d23040caa8b ("KVM: guest_memfd: Use AS_INACCESSIBLE when creating guest_memfd inode")
Fixes: c72ceafbd12c ("mm: Introduce AS_INACCESSIBLE for encrypted/confidential memory")
Cc: linux-mm@kvack.org
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Michael Roth <michael.roth@amd.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
The folio_migrate_copy() is just a wrapper of folio_copy() and
folio_migrate_flags(), it is simple and only aio use it for now, unfold it
and remove folio_migrate_copy().
Link: https://lkml.kernel.org/r/20240626085328.608006-7-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: Lance Yang <ioworker0@gmail.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: Oscar Salvador <osalvador@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
This is similar to __migrate_folio(), use folio_mc_copy() in HugeTLB folio
migration to avoid panic when copy from poisoned folio.
Link: https://lkml.kernel.org/r/20240626085328.608006-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@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: Jane Chu <jane.chu@oracle.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Lance Yang <ioworker0@gmail.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: Oscar Salvador <osalvador@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The folio migration is widely used in kernel, memory compaction, memory
hotplug, soft offline page, numa balance, memory demote/promotion, etc,
but once access a poisoned source folio when migrating, the kerenl will
panic.
There is a mechanism in the kernel to recover from uncorrectable memory
errors, ARCH_HAS_COPY_MC, which is already used in other core-mm paths,
eg, CoW, khugepaged, coredump, ksm copy, see copy_mc_to_{user,kernel},
copy_mc_{user_}highpage callers.
In order to support poisoned folio copy recover from migrate folio, we
chose to make folio migration tolerant of memory failures and return error
for folio migration, because folio migration is no guarantee of success,
this could avoid the similar panic shown below.
CPU: 1 PID: 88343 Comm: test_softofflin Kdump: loaded Not tainted 6.6.0
pc : copy_page+0x10/0xc0
lr : copy_highpage+0x38/0x50
...
Call trace:
copy_page+0x10/0xc0
folio_copy+0x78/0x90
migrate_folio_extra+0x54/0xa0
move_to_new_folio+0xd8/0x1f0
migrate_folio_move+0xb8/0x300
migrate_pages_batch+0x528/0x788
migrate_pages_sync+0x8c/0x258
migrate_pages+0x440/0x528
soft_offline_in_use_page+0x2ec/0x3c0
soft_offline_page+0x238/0x310
soft_offline_page_store+0x6c/0xc0
dev_attr_store+0x20/0x40
sysfs_kf_write+0x4c/0x68
kernfs_fop_write_iter+0x130/0x1c8
new_sync_write+0xa4/0x138
vfs_write+0x238/0x2d8
ksys_write+0x74/0x110
Note, folio copy is moved in the begin of the __migrate_folio(), which
could simplify the error handling since there is no turning back if
folio_migrate_mapping() return success, the downside is the folio copied
even though folio_migrate_mapping() return fail, an optimization is to
check whether source folio does not have extra refs before we do folio
copy.
Link: https://lkml.kernel.org/r/20240626085328.608006-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@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: Jane Chu <jane.chu@oracle.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Lance Yang <ioworker0@gmail.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: Oscar Salvador <osalvador@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The folio refcount check is moved out for both !mapping and mapping folio,
also update comment from page to folio for folio_migrate_mapping().
No functional change intended.
Link: https://lkml.kernel.org/r/20240626085328.608006-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@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: Jane Chu <jane.chu@oracle.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Lance Yang <ioworker0@gmail.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: Oscar Salvador <osalvador@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
crashes from deferred split racing folio migration", needed by "mm:
migrate: split folio_migrate_mapping()".
|
|
Even on 6.10-rc6, I've been seeing elusive "Bad page state"s (often on
flags when freeing, yet the flags shown are not bad: PG_locked had been
set and cleared??), and VM_BUG_ON_PAGE(page_ref_count(page) == 0)s from
deferred_split_scan()'s folio_put(), and a variety of other BUG and WARN
symptoms implying double free by deferred split and large folio migration.
6.7 commit 9bcef5973e31 ("mm: memcg: fix split queue list crash when large
folio migration") was right to fix the memcg-dependent locking broken in
85ce2c517ade ("memcontrol: only transfer the memcg data for migration"),
but missed a subtlety of deferred_split_scan(): it moves folios to its own
local list to work on them without split_queue_lock, during which time
folio->_deferred_list is not empty, but even the "right" lock does nothing
to secure the folio and the list it is on.
Fortunately, deferred_split_scan() is careful to use folio_try_get(): so
folio_migrate_mapping() can avoid the race by folio_undo_large_rmappable()
while the old folio's reference count is temporarily frozen to 0 - adding
such a freeze in the !mapping case too (originally, folio lock and
unmapping and no swap cache left an anon folio unreachable, so no freezing
was needed there: but the deferred split queue offers a way to reach it).
Link: https://lkml.kernel.org/r/29c83d1a-11ca-b6c9-f92e-6ccb322af510@google.com
Fixes: 9bcef5973e31 ("mm: memcg: fix split queue list crash when large folio migration")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Currently we always take a folio reference even if migration will not even
be tried or isolation failed, requiring us to grab+drop an additional
reference.
Further, we end up calling folio_likely_mapped_shared() while the folio
might have already been unmapped, because after we dropped the PTL, that
can easily happen. We want to stop touching mapcounts and friends from
such context, and only call folio_likely_mapped_shared() while the folio
is still mapped: mapcount information is pretty much stale and unreliable
otherwise.
So let's move checks into numamigrate_isolate_folio(), rename that
function to migrate_misplaced_folio_prepare(), and call that function from
callsites where we call migrate_misplaced_folio(), but still with the PTL
held.
We can now stop taking temporary folio references, and really only take a
reference if folio isolation succeeded. Doing the
folio_likely_mapped_shared() + folio isolation under PT lock is now
similar to how we handle MADV_PAGEOUT.
While at it, combine the folio_is_file_lru() checks.
[david@redhat.com: fix list_del() corruption]
Link: https://lkml.kernel.org/r/8f85c31a-e603-4578-bf49-136dae0d4b69@redhat.com
Link: https://lkml.kernel.org/r/20240626191129.658CFC32782@smtp.kernel.org
Link: https://lkml.kernel.org/r/20240620212935.656243-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/migrate: move NUMA hinting fault folio isolation + checks
under PTL".
Let's just return 0 on success, which is less confusing.
... especially because we got it wrong in the migrate.h stub where we
have "return -EAGAIN; /* can't migrate now */" instead of "return 0;".
Likely this wrong return value doesn't currently matter, but it certainly
adds confusion.
We'll add migrate_misplaced_folio_prepare() next, where we want to use the
same "return 0 on success" approach, so let's just clean this up.
Link: https://lkml.kernel.org/r/20240620212935.656243-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240620212935.656243-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
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
set in hmm, as the MIGRATE_SYNC_NO_COPY set is removed by previous
cleanup, it seems that we could remove the unnecessary
MIGRATE_SYNC_NO_COPY.
Link: https://lkml.kernel.org/r/20240524052843.182275-6-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>
|
|
migrate_folio_extra() is only called in migrate.c now, convert it a static
function and take a new src_private argument which could be shared by
migrate_folio() and filemap_migrate_folio() to simplify code a bit.
Link: https://lkml.kernel.org/r/20240524052843.182275-5-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>
|
|
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>
|
|
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>
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I hit the VM_BUG_ON(!list_empty(&cc->migratepages)) in compact_zone(); and
if DEBUG_VM were off, then pages would be lost on a local list.
Our convention is that if migrate_pages() reports complete success (0),
then the migratepages list will be empty; but if it reports an error or
some pages remaining, then its caller must putback_movable_pages().
There's a new case in which migrate_pages() has been reporting complete
success, but returning with pages left on the migratepages list: when
migrate_pages_batch() successfully split a folio on the deferred list, but
then the "Failure isn't counted" call does not dispose of them all.
Since that block is expecting the large folio to have been counted as 1
failure already, and since the return code is later adjusted to success
whenever the returned list is found empty, the simple way to fix this
safely is to count splitting the deferred folio as "a failure".
Link: https://lkml.kernel.org/r/46c948b4-4dd8-6e03-4c7b-ce4e81cfa536@google.com
Fixes: 7262f208ca68 ("mm/migrate: split source folio if it is on deferred split list")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The page is only used to get the mapping, so the folio will do just as
well. Both callers already have a folio available, so this saves a call
to compound_head().
Link: https://lkml.kernel.org/r/20240412193510.2356957-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In ksm stable tree all page are single, let's convert them to use and
folios as well as stable_tree_insert/stable_tree_search funcs. And
replace get_ksm_page() by ksm_get_folio() since there is no more needs.
It could save a few compound_head calls.
Link: https://lkml.kernel.org/r/20240411061713.1847574-9-alexs@kernel.org
Signed-off-by: Alex Shi (tencent) <alexs@kernel.org>
Cc: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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