The previous patch fixed this issue for the traditional LRU. The same
problem exists in MGLRU [1]: when swappiness=max (SWAPPINESS_ANON_ONLY) is
set, reclaim is expected to evict anonymous pages exclusively, but file
pages can still be reclaimed when anonymous pages cannot be reclaimed
(e.g. no swap and no demotion target).
Fix it the same way as the traditional LRU: keep returning
SWAPPINESS_ANON_ONLY in get_swappiness(), and return 0 from
get_nr_to_scan() when SWAPPINESS_ANON_ONLY is set but anon pages cannot be
reclaimed. Since get_nr_to_scan() decides how much MGLRU scans, returning
0 skips the scan entirely and avoids the useless scan work when there is
nothing eligible to reclaim.
The test result:
Before fix:
# cat /sys/kernel/mm/lru_gen/enabled
0x0007
# cat memory.stat
anon 204800
file 67108864
...
pgsteal_proactive 0
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
# cat memory.stat
anon 208896
file 0
...
pgsteal_proactive 16384
pgscan_proactive 16384
After fix:
# cat memory.stat
anon 188416
file 67215360
kernel 1970176
...
pgsteal_proactive 0
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
-bash: echo: write error: Resource temporarily unavailable
# cat memory.stat
anon 204800
file 67215360
...
pgsteal_proactive 0
pgscan_proactive 0
Link: https://lore.kernel.org/20260724033435.2573323-5-ridong.chen@linux.dev
Link: https://sashiko.dev/#/patchset/20260717113300.214717-1-ridong.chen@linux.dev [1]
Fixes: 68a1436bde ("mm: add swappiness=max arg to memory.reclaim for only anon reclaim")
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Reviewed-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/vmscan: fix swappiness=max and clean up per-node
proactive reclaim", v4.
Fixes and one cleanup.
Patch 1 fixes "swappiness=max": the anon-only test in get_scan_count() sat
after the "cannot reclaim anon" check, so when no anon was reclaimable the
request fell back to SCAN_FILE and evicted page cache instead.
Patch 2 fixes reclaim_store() collapsing every error into -EAGAIN, so
callers can no longer tell an invalid argument from a busy interface;
propagate the real error code, matching the memcg path.
Patch 3 drops the now-unused gfp_mask parameter from __node_reclaim().
Patch 4 fixes the same "swappiness=max" issue for MGLRU.
This patch (of 4):
As Qi mentioned [1], when swappiness=max (SWAPPINESS_ANON_ONLY) is set,
the reclaim logic is expected to reclaim anonymous pages exclusively.
However, due to the current ordering of checks in get_scan_count(), file
pages may still be evicted if can_reclaim_anon_pages() returns false,
which contradicts the semantics of SWAPPINESS_ANON_ONLY.
Reproducer in a cgroup holding 64M of file cache, with no swap configured:
Before (file cache is wrongly evicted):
# cat memory.stat
anon 196608
file 67178496
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
# cat memory.stat
anon 208896
file 4096 <- page cache evicted
pgsteal_proactive 16400
pgscan_proactive 16400
After (file cache is left intact):
# cat memory.stat
anon 200704
file 67178496
pgscan_proactive 0
# echo "64M swappiness=max" > memory.reclaim
-bash: echo: write error: Resource temporarily unavailable
# cat memory.stat
anon 208896
file 67178496 <- page cache untouched
pgsteal_proactive 0
pgscan_proactive 0
Fix this by bailing out early when SWAPPINESS_ANON_ONLY is set and no
anonymous pages are reclaimable, before falling back to file reclaim.
Link: https://lore.kernel.org/20260724033435.2573323-1-ridong.chen@linux.dev
Link: https://lore.kernel.org/20260724033435.2573323-2-ridong.chen@linux.dev
Link: https://lore.kernel.org/cgroups/7ddf3eee-5fe2-45f7-8614-c8936a039e04@linux.dev/ [1]
Fixes: 68a1436bde ("mm: add swappiness=max arg to memory.reclaim for only anon reclaim")
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
Suggested-by: Qi Zheng <qi.zheng@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kairui Song <kasong@tencent.com>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 44f65d9006 ("binfmt_elf: mseal address zero") unconditionally
provided do_mseal() to any internal kernel caller in order to address a
corner case slated for possible removal.
It also incorrectly attempts to mseal without checking to see whether the
mapping even succeeded.
Restrict the scope to the corner case by providing mseal_mmap_page_zero()
which asserts the MMAP_PAGE_ZERO personality.
Avoid unnecessary checks in the start, end range by abstracting the actual
mseal()'ing to mseal_range() and have mseal_mmap_page_zero() call that
instead.
Also only try to seal the VMA if we mapped the VMA. This isn't strictly
necessary as the operation would error out anyway, but it's useless work
and could be problematic if me make future changes to mseal semantics.
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-2-0daa0014b813@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mseal: further cleanups", v2.
The mseal implementation is still rather confusing, so tighten things up a
little.
The only user of do_mseal() outside of the system call is the
MMAP_PAGE_ZERO process personality - retain better control over how mseal
is utilised by providing mseal_mmap_page_zero() for this instead.
The comments are overly long and confusion, so cut them down so they're a
lot clearer.
Remove confusing mm_struct params (mseal can not be used on remote mm's)
and wrap the actual system call logic into the system call declaration.
This patch (of 3):
Remove comment blocks that don't add value and eliminate any confusion
about whether or not we permit mseal()'ing of remote mm's by not passing
through an mm parameter but rather referencing current->mm in each
function.
Also while we're here, avoid an ugly goto by using an else branch, and
move local parameters declarations into reverse xmas tree order.
No functional change intended.
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-0-0daa0014b813@kernel.org
Link: https://lore.kernel.org/20260717-mseal-fixups-v2-1-0daa0014b813@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
secretmem_fault() allocates a folio with GFP_HIGHUSER and then calls
set_direct_map_invalid_noflush() without checking folio_test_highmem().
This causes a warning and process crash (vibe-coded reproducer in Link
below):
Su[ 30.071284] ------------[ cut here ]------------
ccessfully allocated and mapped 2097152000 bytes at 0x3a449000
Populating memor[ 30.074614] CPA: called for zero pte. vaddr = 0 cpa->vaddr = 0
y...
[ 30.078636] WARNING: arch/x86/mm/pat/set_memory.c:1840 at __cpa_process_fault+0x34d/0x360, CPU#5: allocate_secret/570
[ 30.084789] CPU: 5 UID: 0 PID: 570 Comm: allocate_secret Not tainted 7.1.0-14063-g4edcdefd4083-dirty #10 PREEMPTLAZY
[ 30.090937] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[ 30.097543] EIP: __cpa_process_fault+0x34d/0x360
[ 30.100514] Code: ff ff 85 c0 0f 89 7d fe ff ff e9 3d fe ff ff 8b 03 8b 00 c7 04 24 c8 ff 64 c1 89 44 24 08 8b 45 e8 89 44 24 04 e8 53 7
a 00 00 <0f> 0b c7 45 f0 f2 ff ff ff e9 fc fc ff ff 90 8d 74 26 00 55 25 00
[ 30.110829] EAX: 00000000 EBX: f64afe98 ECX: 00000000 EDX: 00000000
[ 30.114799] ESI: 00000000 EDI: f64afe98 EBP: f64afe04 ESP: f64afdcc
[ 30.118785] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010246
[ 30.123020] CR0: 80050033 CR2: 46c48ffc CR3: 038c8000 CR4: 00000690
[ 30.127010] Call Trace:
[ 30.129078] __change_page_attr_set_clr+0x5e7/0x870
[ 30.132275] ? console_unlock+0x99/0x130
[ 30.135069] ? irq_work_queue+0x36/0x70
[ 30.137853] ? page_address+0xd3/0xf0
[ 30.140421] set_direct_map_invalid_noflush+0x52/0x60
[ 30.143782] secretmem_fault+0x128/0x210
[ 30.146560] __do_fault+0x25/0x90
[ 30.149053] handle_mm_fault+0x6d1/0xcb0
[ 30.151759] exc_page_fault+0x135/0x3b0
[ 30.154487] ? doublefault_shim+0x150/0x150
[ 30.157416] handle_exception+0x130/0x130
[ 30.160137] EIP: 0x804d29f
[ 30.162307] Code: 89 54 08 e1 89 54 08 e5 89 54 08 e9 89 54 08 ed c3 0f b6 44 24 08 89 7c 24 0c 69 c0 01 01 01 01 8b 7c 24 04 f7 c7 0f 0
0 00 00 <89> 44 0f fc 75 0e c1 e9 02 f3 ab 8b 44 24 04 8b 7c 24 0c c3 31 d2
[ 30.172936] EAX: 5a5a5a5a EBX: 00000000 ECX: 0c800000 EDX: 3a449000
[ 30.176927] ESI: 00000000 EDI: 3a449000 EBP: bfbbae18 ESP: bfbbadac
[ 30.180897] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00010246
[ 30.185161] ? doublefault_shim+0x150/0x150
[ 30.187979] ---[ end trace 0000000000000000 ]---
Bus error (core dumped) ./allocate_secret_i686 2000M
The equivalent bug was pointed out by a local Sashiko instance on
https://lore.kernel.org/all/20260410151746.61150-3-kalyazin@amazon.com/
This hasn't been reproduced it on older kernel versions but from code
inspection the bug seems to go back to the original introduction in commit
1507f51255 ("mm: introduce memfd_secret system call to create "secret"
memory areas"). If this configuration has always been broken, there's no
need to worry too much about feature regression here.
Nonetheless, instead of just completely disabling secretmem under
!HIGHMEM, just drop __GFP_HIGHMEM. This means that now where you
previously got a crash, instead you'll just see the secretmem process OOM.
Could secretmem just support highmem by saying "this isn't in the direct
map anyway" and bailing out before the set_direct_map_invalid_noflush()?
Maybe. That depends on requirements that are not well-defined (e.g. is
it OK that kmap_local_page() is not a NOP for those pages?), and would
require some research and deep thinking. Let's "defer" that until an
actual usecase arises.
Link: 7b2acba2d3
Link: https://lore.kernel.org/20260717-secretmem-highmem-v2-1-1f1a961ca91e@google.com
Link: https://lore.kernel.org/all/20260704192603.40aa80cf9242b77aa75e8d8d@linux-foundation.org/
Fixes: 1507f51255 ("mm: introduce memfd_secret system call to create "secret" memory areas")
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_sysfs_apply_inputs() reads ops_id twice. It could race with
ops_id_store(). As a result, the min_region_sz could wrongly be set up.
Read it once.
The user impact is trivial. Sane users ain't update the parameter in
parallel. Even if it happens, the DAMON core layer handles the wrong
min_region_sz (!is_power_of_2()). Even if somehow the race ended up
making a min_region_sz that is different from the user's intention but
still valid, only monitoring itself runs differently than expected. No
critical consequences like kernel panic or memory corruption happen
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-7-sj@kernel.org
Link: https://lore.kernel.org/20260703172417.95426-1-sj@kernel.org [1]
Fixes: 8d009da32f ("mm/damon/sysfs: set damon_ctx->min_sz_region only for paddr use case")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_sysfs_apply_inputs() reads addr_unit twice. It could race with
addr_unit_store(). As a result, the min_region_sz could wrongly be set
up. Read it once.
The user impact is trivial. Sane users ain't update the parameter in
parallel. Even if it happens, the DAMON core layer handles the wrong
min_region_sz (!is_power_of_2()). Even if somehow the race ended up
making a min_region_sz that is different from the user's intention but
still valid, only monitoring itself runs differently than expected. No
critical consequences like kernel panic or memory corruption happen.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-6-sj@kernel.org
Link: https://lore.kernel.org/20260714142950.100711-1-sj@kernel.org [1]
Fixes: 540a2aebc6 ("mm/damon/sysfs: implement addr_unit file under context dir")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.18.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It can race when multiple kdamonds are being used. The problem from the
race is doubtful, but the gain from the optimization is also doubtful.
Simply drop the optimization in favor of code simplicity.
The user impact is doubtfully trivial. After all, this kind of
interference can happen only by intentional user setup. Even if it
happens, it will be rare, and the consequence is degradation of the
best-effort monitoring results. No critical consequences like kernel
panic or memory corruption happen.
The race was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-5-sj@kernel.org
Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1]
Fixes: a28397beb5 ("mm/damon: implement primitives for physical address space monitoring")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.16.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The optimization can race when multiple kdamonds are running. Meanwhile,
the impact of the optimization is quite doubtful. Just remove it.
The user impact of the issue should be quite trivial. After all, the race
can happen only when the user intentionally setup DAMON in the way. Even
if it happens, it would be rare and only degrade the best-effort
monitoring results. No critical consequences like kernel panic or memory
corruption happen.
The race possibility was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-4-sj@kernel.org
Link: https://lore.kernel.org/20260621204050.10993-1-sj@kernel.org [1]
Fixes: 3f49584b26 ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KUNIT_EXPECT_EQ() does not abort the execution of test code when the
expectation is not met. But damon_test_merge_regions_of() code after its
initial KUNIT_EXPECT_EQ() call assumes the expectation is met. It does a
per-region test with a hard-coded number of regions that is correct only
if the expectation was met. As a result, __nth_region_of() could return
NULL, and the test code can dereference NULL pointers. Fix the issue by
catching the expectation failure and skip the per-region tests.
The user impact on realistic setups should be negligible, as it is a unit
test.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-3-sj@kernel.org
Link: https://lore.kernel.org/20260710144937.26981-1-sj@kernel.org [1]
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon: unurgent fixes for infinite loop, NULL de-ref and
races", v1.1.
Sashiko found a few issues in DAMON that could cause infinite loop, NULL
dereference and monitoring results degradation. The first two sounds
scary but the infinite loop happens only under unreasonable user setup.
The NULL dereference is only in a unit test. Monitoring results
degradation is trivial since it is only best-effort, and those happens
from only unlikely races. Still those are bugs that better to fix if
possible. Fix those.
This patch (of 6):
Due to online parameter update like events, the number of DAMON regions
could be higher than the user-set upper limit. kdamond_merge_regions()
repeats merge regions until the number meets the limit, while doubling the
merge threshold up to the theoretical maximum threshold. It is tried only
up to the theoretical maximum threshold because even the aggressive
merging can fail from reducing the number of regions under the
user-defined upper limit. For example, there could be many user-defined
non-contiguous regions that cannot be merged.
The threshold based loop break condition is evaluated by comparing the
threshold for the next merging try against the theoretical maximum
threshold. If max_thres is larger than UINT_MAX / 2, doubling the
threshold could make it overflow, and bypass the loop break condition. In
the case, if the number of regions cannot be reduced under the upper limit
like explained above, the loop will run infinitely.
Prevent the case by doing the break condition check before doubling the
threshold. Also, prevent the threshold exceeding the maximum threshold,
as it could overflow and apply the wrong merge threshold.
This issue is unlikely to occur in real world, since having the max_thres
higher than UINT_MAX / 2 require unrealistically large aggregation
intervals compared to the sampling interval. Also, it requires an
unrealistically large number of uncontiguous regions setup. Nonetheless,
the consequence is bad and the fix is simple.
The issue was discovered [1] by Sashiko.
Link: https://lore.kernel.org/20260715031002.108504-1-sj@kernel.org
Link: https://lore.kernel.org/20260715031002.108504-2-sj@kernel.org
Link: https://lore.kernel.org/20260709145425.96247-1-sj@kernel.org [1]
Fixes: 310d6c15e9 ("mm/damon/core: merge regions aggressively when max_nr_regions is unmet")
Signed-off-by: SJ Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> # 6.10.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is only one caller, get_page_from_freelist(), and it does not make
any use of the reason for skipping the reclaim, nor does it make any
distinction between a full and partially successful reclaim.
Therefore, node_reclaim() can simply return the number of pages that have
been reclaimed, same as __node_reclaim(), and the NODE_RECLAIM_xxx macros
can be removed.
There is one small change of behavior when __node_reclaim() was attempted
but returned zero. The allocation now skips the zone immediately; before
this patch, the zone watermarks were checked first. I believe it was an
oversight rather than intention, because the chances that zone watermark
is OK after __node_reclaim() did not reclaim any pages are very close to
zero.
Originally, I was looking for occurences of NODE_RECLAIM_SOME and
NODE_RECLAIM_SUCCESS, but I couldn't find any. That's because they are
typecast from the result of a relational operator. This seemed a bit
fragile, so I dug a bit deeper and came up with this proposed cleanup.
Link: https://lore.kernel.org/20260714132300.2136018-1-ptesarik@suse.com
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_ctx->ops field is intended to be used by only the DAMON core layer.
DAMON_SYSFS is directly reading the field to find if it is for physical
address monitoring, though. Use the API function for the purpose,
damon_target_has_pid(), instead.
Link: https://lore.kernel.org/20260714143544.101305-10-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/damon/core: hide core-private struct fields".
DAMON core structs hide core-private fields using 'private:' comment tags.
It is incomplete and inconsistent. The linked list heads in a few
structs, for example, are intended to be hidden, and always be used using
the wrapper macros like damon_for_each_region(). But those were
mistakenly marked as non-private. A few core layer-only fields were also
mistakenly added as non-private.
This only encourages callers to directly use the private fields. It is
easy to make mistakes, and difficult to control. Mark all such DAMON core
struct fields as private.
Patches 1-8 mark the private fields for damon_region, damon_target,
damos_quota_goal, damos_quota, damos_filter, damos, damon_filter and
damon_probe, respectively. Patch 9 removes DAMON_SYSFS's direct access to
core-private field, damon_ctx->ops. Finally patch 10 mark the private
fields for damon_ctx.
This patch (of 10):
damon_region->list is intended to be used by only the DAMON core layer.
But it is mistakenly not marked as private. Hide it from the callers by
marking it private.
Link: https://lore.kernel.org/20260714143544.101305-1-sj@kernel.org
Link: https://lore.kernel.org/20260714143544.101305-2-sj@kernel.org
Signed-off-by: SJ Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The core do_mmap() function accepts a vm_flags_t parameter which it then
manipulates before passing to mmap_region() to do the heavy lifting of the
memory mapping.
Update do_mmap() to instead accept a vma_flags_t parameter, and adjust all
the logic within do_mmap() to manipulate this instead.
This is as part of the ongoing effort to convert VMA flags from a system
word size to a bitmap type which allows us to unrestrict the number of VMA
flags, as well as gain control over how VMA flag manipulation occurs.
We do not cascade these changes to all functions which accept vm_flags_t,
but rather use vma_flags_to_legacy() where necessary, specifically
deferring converting calc_vm_prot_bits(), calc_vm_flag_bits() and
__get_unmapped_area() to vma_flags_t.
Also utilise the new vma_flags_can_grow() predicate which correctly
handles the case of architectures without upward growing stacks.
As part of this change, introduce VMA_SHADOW_STACK so we can correctly
handle the case of the shadow stack not being defined.
No functional change intended.
Link: https://lore.kernel.org/20260711-b4-vma-flags-mm-v2-2-0fa2357d5431@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a kselftest for the dax/kmem whole-device "state" sysfs attribute
(/sys/bus/dax/devices/daxX.Y/state), which transitions a kmem-backed
dax device between "unplugged", "online" and "online_movable".
The kselftest also includes a test to demonstrate the force-unbind
does not deadlock - but this is destructive (the dax device can never
be rebound), so it only runs when DAX_KMEM_TEST_UNBIND=1 is set.
Provisioning a devdax device and binding it to kmem needs daxctl/ndctl
out of scope for an in-tree selftest. As the test mutates a device's
memory, the operator opts in by naming it in DAX_KMEM_TEST_DEV (or
"auto" to pick the first kmem-bound device); it SKIPs when unset, when
no device is present, or when the memory cannot be freed to a baseline.
When a device is available it validates the interface contract:
- online / online_movable actually add memory (MemTotal grows),
- online is idempotent,
- switching between online types without unplug is rejected,
- unplug removes memory and the reported state is "unplugged"
- invalid input is rejected,
- unplug and unbind tolerate blocks toggled out-of-band through the
per-block memoryX/state interface.
One specific regression test:
online -> unplug -> online_movable -> unplug
Re-online must re-reserve per-range resources so subsequent unplug
actually offlines and removes instead of silently reporting success
while the memory stays online.
Link: https://lore.kernel.org/20260712154505.3564379-11-gourry@gourry.net
Signed-off-by: Gregory Price <gourry@gourry.net>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pankaj Gupta <pankaj.gupta@amd.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
