- 05 Jul, 2024 12 commits
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Roman Gushchin authored
Cgroup v1's memory controller contains a pretty complicated event notifications mechanism which is not used on cgroup v2. Let's move the corresponding code into memcontrol-v1.c. Please, note, that mem_cgroup_event_ratelimit() remains in memcontrol.c, otherwise it would require exporting too many details on memcg stats outside of memcontrol.c. Link: https://lkml.kernel.org/r/20240625005906.106920-7-roman.gushchin@linux.devSigned-off-by:
Roman Gushchin <roman.gushchin@linux.dev> Acked-by:
Michal Hocko <mhocko@suse.com> Acked-by:
Shakeel Butt <shakeel.butt@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Roman Gushchin authored
Rename exported function related to the charge move to have the memcg1_ prefix. Link: https://lkml.kernel.org/r/20240625005906.106920-6-roman.gushchin@linux.devSigned-off-by:
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Roman Gushchin authored
Unlike the legacy cgroup v1 memory controller, cgroup v2 memory controller doesn't support moving charged pages between cgroups. It's a fairly large and complicated code which created a number of problems in the past. Let's move this code into memcontrol-v1.c. It shaves off 1k lines from memcontrol.c. It's also another step towards making the legacy memory controller code optionally compiled. Link: https://lkml.kernel.org/r/20240625005906.106920-5-roman.gushchin@linux.devSigned-off-by:
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Roman Gushchin authored
Rename exported function related to the softlimit reclaim to have memcg1_ prefix. Link: https://lkml.kernel.org/r/20240625005906.106920-4-roman.gushchin@linux.devSigned-off-by:
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Roman Gushchin authored
Soft limits are cgroup v1-specific and are not supported by cgroup v2, so let's move the corresponding code into memcontrol-v1.c. Aside from simple moving the code, this commits introduces a trivial memcg1_soft_limit_reset() function to reset soft limits and also moves the global soft limit tree initialization code into a new memcg1_init() function. It also moves corresponding declarations shared between memcontrol.c and memcontrol-v1.c into mm/memcontrol-v1.h. Link: https://lkml.kernel.org/r/20240625005906.106920-3-roman.gushchin@linux.devSigned-off-by:
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Roman Gushchin authored
Patch series "mm: memcg: separate legacy cgroup v1 code and put under config option", v2. Cgroups v2 have been around for a while and many users have fully adopted them, so they never use cgroups v1 features and functionality. Yet they have to "pay" for the cgroup v1 support anyway: 1) the kernel binary contains an unused cgroup v1 code, 2) some code paths have additional checks which are not needed, 3) some common structures like task_struct and mem_cgroup contain unused cgroup v1-specific members. Cgroup v1's memory controller has a number of features that are not supported by cgroup v2 and their implementation is pretty much self contained. Most notably, these features are: soft limit reclaim, oom handling in userspace, complicated event notification system, charge migration. Cgroup v1-specific code in memcontrol.c is close to 4k lines in size and it's intervened with generic and cgroup v2-specific code. It's a burden on developers and maintainers. This patchset aims to solve these problems by: 1) moving cgroup v1-specific memcg code to the new mm/memcontrol-v1.c file, 2) putting definitions shared by memcontrol.c and memcontrol-v1.c into the mm/memcontrol-v1.h header, 3) introducing the CONFIG_MEMCG_V1 config option, turned off by default, 4) making memcontrol-v1.c to compile only if CONFIG_MEMCG_V1 is set. If CONFIG_MEMCG_V1 is not set, cgroup v1 memory controller is still available for mounting, however no memory-specific control knobs are present. This patch (of 14): This patch introduces the mm/memcontrol-v1.c source file which will be used for all legacy (cgroup v1) memory cgroup code. It also introduces mm/memcontrol-v1.h to keep declarations shared between mm/memcontrol.c and mm/memcontrol-v1.c. As of now, let's compile it if CONFIG_MEMCG is set, similar to mm/memcontrol.c. Later on it can be switched to use a separate config option, so that the legacy code won't be compiled if not required. Link: https://lkml.kernel.org/r/20240625005906.106920-1-roman.gushchin@linux.dev Link: https://lkml.kernel.org/r/20240625005906.106920-2-roman.gushchin@linux.devSigned-off-by:
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Chengming Zhou authored
Now the implementation of stable_node_dup() causes chain()/chain_prune() interfaces and usages are overcomplicated. Why? stable_node_dup() only find and return a candidate stable_node for sharing, so the users have to recheck using stable_node_dup_any() if any non-candidate stable_node exist. And try to ksm_get_folio() from it again. Actually, stable_node_dup() can just return a best stable_node as it can, then the users can check if it's a candidate for sharing or not. The code is simplified too and fewer corner cases: such as stable_node and stable_node_dup can't be NULL if returned tree_folio is not NULL. Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-3-1c328aa9e30b@linux.devSigned-off-by:
Chengming Zhou <chengming.zhou@linux.dev> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Stefan Roesch <shr@devkernel.io> Signed-off-by:
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Chengming Zhou authored
The code flow in cmp_and_merge_page() is suboptimal for handling the ksm page and non-ksm page at the same time. For example: - ksm page 1. Mostly just return if this ksm page is not migrated and this rmap_item has been on the rmap hlist. Or we have to fix this rmap_item mapping. 2. But we absolutely don't need to checksum for this ksm page, since it can't change. - non-ksm page 1. First don't need to waste time searching stable tree if fast changing. 2. Should try to merge with zero page before search the stable tree. 3. Then search stable tree to find mergeable ksm page. This patch optimizes the code flow so the handling differences between ksm page and non-ksm page become clearer and more efficient too. Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-2-1c328aa9e30b@linux.devSigned-off-by: -
Chengming Zhou authored
Patch series "mm/ksm: cmp_and_merge_page() optimizations and cleanup", v2. This series mainly optimizes cmp_and_merge_page() to have more efficient separate code flow for ksm page and non-ksm anon page. - ksm page: don't need to calculate the checksum obviously. - anon page: don't need to search stable tree if changing fast and try to merge with zero page before searching ksm page on stable tree. Please see the patch-2 for details. Patch-3 is cleanup also a little optimization for the chain()/chain_prune interfaces, which made the stable_tree_search()/stable_tree_insert() over complex. I have done simple testing using "hackbench -g 1 -l 300000" (maybe I need to use a better workload) on my machine, have seen a little CPU usage decrease of ksmd and some improvements of cmp_and_merge_page() latency: We can see the latency of cmp_and_merge_page() when handling non-ksm anon pages has been improved. This patch (of 3): In preparation for later changes, refactor out a new function called try_to_merge_with_zero_page(), which tries to merge with zero page. Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-0-1c328aa9e30b@linux.dev Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-1-1c328aa9e30b@linux.devSigned-off-by:
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Aristeu Rozanski authored
When trying to allocate a hugepage with no reserved ones free, it may be allowed in case a number of overcommit hugepages was configured (using /proc/sys/vm/nr_overcommit_hugepages) and that number wasn't reached. This allows for a behavior of having extra hugepages allocated dynamically, if there're resources for it. Some sysadmins even prefer not reserving any hugepages and setting a big number of overcommit hugepages. But while attempting to allocate overcommit hugepages in a multi node system (either NUMA or mempolicy/cpuset) said allocations might randomly fail even when there're resources available for the allocation. This happens due to allowed_mems_nr() only accounting for the number of free hugepages in the nodes the current process belongs to and the surplus hugepage allocation is done so it can be allocated in any node. In case one or more of the requested surplus hugepages are allocated in a different node, the whole allocation will fail due allowed_mems_nr() returning a lower value. So allocate surplus hugepages in one of the nodes the current process belongs to. Easy way to reproduce this issue is to use a 2+ NUMA nodes system: # echo 0 >/proc/sys/vm/nr_hugepages # echo 1 >/proc/sys/vm/nr_overcommit_hugepages # numactl -m0 ./tools/testing/selftests/mm/map_hugetlb 2 Repeating the execution of map_hugetlb test application will eventually fail when the hugepage ends up allocated in a different node. [aris@ruivo.org: v2] Link: https://lkml.kernel.org/r/20240701212343.GG844599@cathedrallabs.org Link: https://lkml.kernel.org/r/20240621190050.mhxwb65zn37doegp@redhat.comSigned-off-by:
Aristeu Rozanski <aris@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Aristeu Rozanski <aris@ruivo.org> Cc: David Hildenbrand <david@redhat.com> Cc: Vishal Moola <vishal.moola@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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SeongJae Park authored
The variable is supposed to be set via later migrate_pages() call. However, the function does not do that when CONFIG_MIGRATION is unset. Initialize the variable to zero. Link: https://lkml.kernel.org/r/20240701165332.47495-1-sj@kernel.org Fixes: 5311c0a2eee3 ("mm/damon/paddr: introduce DAMOS_MIGRATE_COLD action for demotion") Signed-off-by:
SeongJae Park <sj@kernel.org> Reported-by:
kernel test robot <lkp@intel.com> Reported-by:
Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/r/202406251102.GE07hqfQ-lkp@intel.com/ Cc: Honggyu Kim <honggyu.kim@sk.com> Cc: Hyeongtak Ji <hyeongtak.ji@sk.com> Signed-off-by:
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Kefeng Wang authored
Folios of order <= 1 are not in deferred list, the check of order is added into folio_undo_large_rmappable() from commit 8897277a ("mm: support order-1 folios in the page cache"), but there is a repeated check for small folio (order 0) during each call of the folio_undo_large_rmappable(), so only keep folio_order() check inside the function. In addition, move all the checks into header file to save a function call for non-large-rmappable or empty deferred_list folio. Link: https://lkml.kernel.org/r/20240521130315.46072-1-wangkefeng.wang@huawei.comSigned-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.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:
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- 04 Jul, 2024 28 commits
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SeongJae Park authored
User could update max_nr_regions parameter while DAMON is running to a value that smaller than the current number of regions that DAMON is seeing. Such update could be done for reducing the monitoring overhead. In the case, DAMON should merge regions aggressively more than normal situation to ensure the new limit is successfully applied. Implement a kselftest to ensure that. Link: https://lkml.kernel.org/r/20240625180538.73134-9-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Users can update DAMON parameters while it is running, using 'commit' DAMON sysfs interface command. For testing the feature in future tests, implement a function for doing that on the test-purpose DAMON sysfs interface wrapper Python module. Link: https://lkml.kernel.org/r/20240625180538.73134-8-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Implement a kselftest for DAMON's {min,max}_nr_regions' parameters. The test ensures both the minimum and the maximum number of regions limit is respected even if the workload's real number of regions is less than the minimum or larger than the maximum limits. Link: https://lkml.kernel.org/r/20240625180538.73134-7-sj@kernel.orgSigned-off-by: -
SeongJae Park authored
Implement DAMON stop function on the test-purpose DAMON sysfs interface wrapper Python module, _damon_sysfs.py. This feature will be used by future DAMON tests that need to start/stop DAMON multiple times. Link: https://lkml.kernel.org/r/20240625180538.73134-6-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Implement a test for DAMOS tried regions command of DAMON sysfs interface. It ensures the expected number of monitoring regions are created using an artificial memory access pattern generator program. Link: https://lkml.kernel.org/r/20240625180538.73134-5-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
To test schemes_tried_regions feature, we need to have a program having specific number of regions that having different access pattern. Existing artificial access pattern generator, 'access_memory', cannot be used for the purpose, since it accesses only one region at a given time. Extending it could be an option, but since the purpose and the implementation are pretty simple, implementing another one from the scratch is better. Implement such another artificial memory access program that allocates user-defined number/size regions and accesses even-numbered regions. Link: https://lkml.kernel.org/r/20240625180538.73134-4-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Implement schemes_update_tried_regions DAMON sysfs command on _damon_sysfs.py, to use on implementations of future tests for the feature. Link: https://lkml.kernel.org/r/20240625180538.73134-3-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Patch series "selftests/damon: test DAMOS tried regions and {min,max}_nr_regions". This patch series fix a minor issue in a program for DAMON selftest, and implement new functionality selftests for DAMOS tried regions and {min,max}_nr_regions. The test for max_nr_regions also test the recovery from online tuning-caused limit violation, which was fixed by a previous patch [1] titled "mm/damon/core: merge regions aggressively when max_nr_regions is unmet". The first patch fixes a minor problem in the articial memory access pattern generator for tests. Following 3 patches (2-4) implement schemes tried regions test. Then a couple of patches (5-6) implementing static setup based {min,max}_nr_regions functionality test follows. Final two patches (7-8) implement dynamic max_nr_regions update test. [1] https://lore.kernel.org/20240624210650.53960C2BBFC@smtp.kernel.org This patch (of 8): 'access_memory' is an artificial memory access pattern generator for DAMON tests. It creates and accesses memory regions that the user specified the number and size via the command line. However, real access part of the program ignores the user-specified size of each region. Instead, it uses a hard-coded value, 10 MiB. Fix it to use user-defined size. Note that all existing 'access_memory' users are setting the region size as 10 MiB. Hence no real problem has happened so far. Link: https://lkml.kernel.org/r/20240625180538.73134-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240625180538.73134-2-sj@kernel.org Fixes: b5906f5f ("selftests/damon: add a test for update_schemes_tried_regions sysfs command") Signed-off-by: -
Jan Kara authored
Unify all conditions for initial readahead to simplify goto logic in page_cache_sync_ra(). No functional changes. Link: https://lkml.kernel.org/r/20240625101909.12234-10-jack@suse.czSigned-off-by:
Jan Kara <jack@suse.cz> Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Tested-by:
Zhang Peng <zhangpengpeng0808@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
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Jan Kara authored
try_context_readahead() has a single caller page_cache_sync_ra(). Fold the function there to make ra state modifications more obvious. No functional changes. Link: https://lkml.kernel.org/r/20240625101909.12234-9-jack@suse.czSigned-off-by:
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Jan Kara authored
Both async and sync readahead are handled by ondemand_readahead() function. However there isn't actually much in common. Just move async related parts into page_cache_ra_async() and sync related parts to page_cache_ra_sync(). No functional changes. Link: https://lkml.kernel.org/r/20240625101909.12234-8-jack@suse.czSigned-off-by:
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Jan Kara authored
ondemand_readahead() scales up the readahead window if the current read would hit the readahead mark placed by itself. However the condition is mostly dead code because: a) In case of async readahead we always increase ra->start so ra->start == index is never true. b) In case of sync readahead we either go through try_context_readahead() in which case ra->async_size == 1 < ra->size or we go through initial_readahead where ra->async_size == ra->size iff ra->size == max_pages. So the only practical effect is reducing async_size for large initial reads. Make the code more obvious. Link: https://lkml.kernel.org/r/20240625101909.12234-7-jack@suse.czSigned-off-by:
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Jan Kara authored
page_cache_ra_order() scales folio order down so that is fully fits within readahead window. Thus the code handling the case where we walked past the readahead window is a dead code. Remove it. Link: https://lkml.kernel.org/r/20240625101909.12234-6-jack@suse.czSigned-off-by:
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Jan Kara authored
The index argument of page_cache_async_readahead() is just folio->index so there's no point in passing is separately. Drop it. Link: https://lkml.kernel.org/r/20240625101909.12234-5-jack@suse.czSigned-off-by:
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Jan Kara authored
Current index to readahead is tracked in readahead_control and properly updated by page_cache_ra_unbounded() (read_pages() in fact). So there's no need to track the index separately in force_page_cache_ra(). Link: https://lkml.kernel.org/r/20240625101909.12234-4-jack@suse.czSigned-off-by:
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Jan Kara authored
When we succeed in creating some folios in page_cache_ra_order() but then need to fallback to single page folios, we don't shorten the amount to read passed to do_page_cache_ra() by the amount we've already read. This then results in reading more and also in placing another readahead mark in the middle of the readahead window which confuses readahead code. Fix the problem by properly reducing number of pages to read. Link: https://lkml.kernel.org/r/20240625101909.12234-3-jack@suse.czSigned-off-by:
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Jan Kara authored
page_cache_next_miss() should return value outside of the specified range when no hole is found. However currently it will return the last index *in* the specified range confusing ondemand_readahead() to think there's a hole in the searched range and upsetting readahead logic. Link: https://lkml.kernel.org/r/20240625101909.12234-2-jack@suse.czSigned-off-by:
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Jan Kara authored
Patch series "mm: Fix various readahead quirks". When we were internally testing performance of recent kernels, we have noticed quite variable performance of readahead arising from various quirks in readahead code. So I went on a cleaning spree there. This is a batch of patches resulting out of that. A quick testing in my test VM with the following fio job file: [global] direct=0 ioengine=sync invalidate=1 blocksize=4k size=10g readwrite=read [reader] numjobs=1 shows that this patch series improves the throughput from variable one in 310-340 MB/s range to rather stable one at 350 MB/s. As a side effect these cleanups also address the issue noticed by Bruz Zhang [1]. [1] https://lore.kernel.org/all/20240618114941.5935-1-zhangpengpeng0808@gmail.com/ Zhang Peng reported: : I test this batch of patch with fio, it indeed has a huge sppedup : in sequential read when block size is 4KiB. The result as follow, : for async read, iodepth is set to 128, and other settings : are self-evident. : : casename upstream withFix speedup : ---------------- -------- -------- ------- : randread-4k-sync 48991 47 : seqread-4k-sync 1162758 14229 : seqread-1024k-sync 1460208 1452522 : randread-4k-libaio 47467 4730 : randread-4k-posixaio 49190 49512 : seqread-4k-libaio 1085932 1234635 : seqread-1024k-libaio 1423341 1402214 -1 : seqread-4k-posixaio 1165084 1369613 1 : seqread-1024k-posixaio 1435422 1408808 -1.8 This patch (of 10): page_cache_sync_ra() is called when a folio we want to read is not in the page cache. It is expected that it creates the folio (and perhaps the following folios as well) and submits reads for them unless some error happens. However if index == ra->start + ra->size, ondemand_readahead() will treat the call as another async readahead hit. Thus ra->start will be advanced and we create pages and queue reads from ra->start + ra->size further. Consequentially the page at 'index' is not created and filemap_get_pages() has to always go through filemap_create_folio() path. This behavior has particularly unfortunate consequences when we have two IO threads sequentially reading from a shared file (as is the case when NFS serves sequential reads). In that case what can happen is: suppose ra->size == ra->async_size == 128, ra->start = 512 T1 T2 reads 128 pages at index 512 - hits async readahead mark filemap_readahead() ondemand_readahead() if (index == expected ...) ra->start = 512 + 128 = 640 ra->size = 128 ra->async_size = 128 page_cache_ra_order() blocks in ra_alloc_folio() reads 128 pages at index 640 - no page found page_cache_sync_readahead() ondemand_readahead() if (index == expected ...) ra->start = 640 + 128 = 768 ra->size = 128 ra->async_size = 128 page_cache_ra_order() submits reads from 768 - still no page found at index 640 filemap_create_folio() - goes on to index 641 page_cache_sync_readahead() ondemand_readahead() - founds ra is confused, trims is to small size finds pages were already inserted And as a result read performance suffers. Fix the problem by triggering async readahead case in ondemand_readahead() only if we are calling the function because we hit the readahead marker. In any other case we need to read the folio at 'index' and thus we cannot really use the current ra state. Note that the above situation could be viewed as a special case of file->f_ra state corruption. In fact two thread reading using the shared file can also seemingly corrupt file->f_ra in interesting ways due to concurrent access. I never saw that in practice and the fix is going to be much more complex so for now at least fix this practical problem while we ponder about the theoretically correct solution. Link: https://lkml.kernel.org/r/20240625100859.15507-1-jack@suse.cz Link: https://lkml.kernel.org/r/20240625101909.12234-1-jack@suse.czSigned-off-by:
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David Hildenbrand authored
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.comSigned-off-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:
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David Hildenbrand authored
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.comSigned-off-by:
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Tetsuo Handa authored
Commit 2b5067a8 ("mm: mmap_lock: add tracepoints around lock acquisition") introduced TRACE_MMAP_LOCK_EVENT() macro using preempt_disable() in order to let get_mm_memcg_path() return a percpu buffer exclusively used by normal, softirq, irq and NMI contexts respectively. Commit 832b5072 ("mm: mmap_lock: use local locks instead of disabling preemption") replaced preempt_disable() with local_lock(&memcg_paths.lock) based on an argument that preempt_disable() has to be avoided because get_mm_memcg_path() might sleep if PREEMPT_RT=y. But syzbot started reporting inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. and inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. messages, for local_lock() does not disable IRQ. We could replace local_lock() with local_lock_irqsave() in order to suppress these messages. But this patch instead replaces percpu buffers with on-stack buffer, for the size of each buffer returned by get_memcg_path_buf() is only 256 bytes which is tolerable for allocating from current thread's kernel stack memory. Link: https://lkml.kernel.org/r/ef22d289-eadb-4ed9-863b-fbc922b33d8d@I-love.SAKURA.ne.jpReported-by:
syzbot <syzbot+40905bca570ae6784745@syzkaller.appspotmail.com> Closes: https://syzkaller.appspot.com/bug?extid=40905bca570ae6784745 Fixes: 832b5072 ("mm: mmap_lock: use local locks instead of disabling preemption") Signed-off-by:
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by:
Axel Rasmussen <axelrasmussen@google.com> Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Ilya Leoshkevich authored
sparse complains about passing NULL pointers as 0. Fix all instances. Link: https://lkml.kernel.org/r/20240627145754.27333-3-iii@linux.ibm.comSigned-off-by:
Ilya Leoshkevich <iii@linux.ibm.com> Reported-by:
Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Signed-off-by:
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Ilya Leoshkevich authored
sparse complains that __user pointers are being passed to functions that expect non-__user ones. In all cases, these functions are in fact working with user pointers, only the tag is missing. Add it. Link: https://lkml.kernel.org/r/20240627145754.27333-2-iii@linux.ibm.comSigned-off-by:
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Ilya Leoshkevich authored
Now that everything else is in place, enable KMSAN in Kconfig. Link: https://lkml.kernel.org/r/20240621113706.315500-39-iii@linux.ibm.comSigned-off-by:
Heiko Carstens <hca@linux.ibm.com> Reviewed-by:
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Ilya Leoshkevich authored
arch_kmsan_get_meta_or_null() finds the lowcore shadow by querying the prefix and calling kmsan_get_metadata() again. kmsan_virt_addr_valid() delegates to virt_addr_valid(). Link: https://lkml.kernel.org/r/20240621113706.315500-38-iii@linux.ibm.comSigned-off-by:
Alexander Gordeev <agordeev@linux.ibm.com> Reviewed-by:
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Ilya Leoshkevich authored
The unwind code can read uninitialized frames. Furthermore, even in the good case, KMSAN does not emit shadow for backchains. Therefore disable it for the unwinding functions. Link: https://lkml.kernel.org/r/20240621113706.315500-37-iii@linux.ibm.comSigned-off-by:
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Ilya Leoshkevich authored
uaccess.h uses instrument_get_user() and instrument_put_user(), which are defined in linux/instrumented.h. Currently we get this header from somewhere else by accident; prefer to be explicit about it and include it directly. Link: https://lkml.kernel.org/r/20240621113706.315500-36-iii@linux.ibm.comSigned-off-by:
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Ilya Leoshkevich authored
put_user() uses inline assembly with precise constraints, so Clang is in principle capable of instrumenting it automatically. Unfortunately, one of the constraints contains a dereferenced user pointer, and Clang does not currently distinguish user and kernel pointers. Therefore KMSAN attempts to access shadow for user pointers, which is not a right thing to do. An obvious fix to add __no_sanitize_memory to __put_user_fn() does not work, since it's __always_inline. And __always_inline cannot be removed due to the __put_user_bad() trick. A different obvious fix of using the "a" instead of the "+Q" constraint degrades the code quality, which is very important here, since it's a hot path. Instead, repurpose the __put_user_asm() macro to define __put_user_{char,short,int,long}_noinstr() functions and mark them with __no_sanitize_memory. For the non-KMSAN builds make them __always_inline in order to keep the generated code quality. Also define __put_user_{char,short,int,long}() functions, which call the aforementioned ones and which *are* instrumented, because they call KMSAN hooks, which may be implemented as macros. The same applies to get_user() as well. Link: https://lkml.kernel.org/r/20240621113706.315500-35-iii@linux.ibm.comSigned-off-by:
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