- 20 Dec, 2023 20 commits
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Ryan Roberts authored
Patch series "Multi-size THP for anonymous memory", v9. A series to implement multi-size THP (mTHP) for anonymous memory (previously called "small-sized THP" and "large anonymous folios"). The objective of this is to improve performance by allocating larger chunks of memory during anonymous page faults: 1) Since SW (the kernel) is dealing with larger chunks of memory than base pages, there are efficiency savings to be had; fewer page faults, batched PTE and RMAP manipulation, reduced lru list, etc. In short, we reduce kernel overhead. This should benefit all architectures. 2) Since we are now mapping physically contiguous chunks of memory, we can take advantage of HW TLB compression techniques. A reduction in TLB pressure speeds up kernel and user space. arm64 systems have 2 mechanisms to coalesce TLB entries; "the contiguous bit" (architectural) and HPA (uarch). This version incorporates David's feedback on the core patches (#3, #4) and adds some RB and TB tags (see change log for details). By default, the existing behaviour (and performance) is maintained. The user must explicitly enable multi-size THP to see the performance benefit. This is done via a new sysfs interface (as recommended by David Hildenbrand - thanks to David for the suggestion)! This interface is inspired by the existing per-hugepage-size sysfs interface used by hugetlb, provides full backwards compatibility with the existing PMD-size THP interface, and provides a base for future extensibility. See [9] for detailed discussion of the interface. This series is based on mm-unstable (715b67adf4c8). Prerequisites ============= I'm removing this section on the basis that I don't believe what we were previously calling prerequisites are really prerequisites anymore. We originally defined them when mTHP was a compile-time feature. There is now a runtime control to opt-in to mTHP; when disabled, correctness and performance are as before. When enabled, the code is still correct/robust, but in the absence of the one remaining item (compaction) there may be a performance impact in some corners. See the old list in the v8 cover letter at [8]. And a longer explanation of my thinking here [10]. SUMMARY: I don't think we should hold this series up, waiting for the items on the prerequisites list. I believe this series should be ready now so hopefully can be added to mm-unstable for some testing, then fingers crossed for v6.8. Testing ======= The series includes patches for mm selftests to enlighten the cow and khugepaged tests to explicitly test with multi-size THP, in the same way that PMD-sized THP is tested. The new tests all pass, and no regressions are observed in the mm selftest suite. I've also run my usual kernel compilation and java script benchmarks without any issues. Refer to my performance numbers posted with v6 [6]. (These are for multi-size THP only - they do not include the arm64 contpte follow-on series). John Hubbard at Nvidia has indicated dramatic 10x performance improvements for some workloads at [11]. (Observed using v6 of this series as well as the arm64 contpte series). Kefeng Wang at Huawei has also indicated he sees improvements at [12] although there are some latency regressions also. I've also checked that there is no regression in the write fault path when mTHP is disabled using a microbenchmark. I ran it for a baseline kernel, as well as v8 and v9. I repeated on Ampere Altra (bare metal) and Apple M2 (VM): | | m2 vm | altra | |--------------|---------------------|---------------------| | kernel | mean | std_rel | mean | std_rel | |--------------|----------|----------|----------|----------| | baseline | 0.000% | 0.341% | 0.000% | 3.581% | | anonfolio-v8 | 0.005% | 0.272% | 5.068% | 1.128% | | anonfolio-v9 | -0.013% | 0.442% | 0.107% | 1.788% | There is no measurable difference on M2, but altra has a slow down in v8 which is fixed in v9 by moving the THP order check to be inline within thp_vma_allowable_orders(), as suggested by David. This patch (of 10): In preparation for the introduction of anonymous multi-size THP, we would like to be able to split them when they have unmapped subpages, in order to free those unused pages under memory pressure. So remove the artificial requirement that the large folio needed to be at least PMD-sized. Link: https://lkml.kernel.org/r/20231207161211.2374093-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20231207161211.2374093-2-ryan.roberts@arm.comSigned-off-by:
Ryan Roberts <ryan.roberts@arm.com> Reviewed-by:
Yu Zhao <yuzhao@google.com> Reviewed-by:
Yin Fengwei <fengwei.yin@intel.com> Reviewed-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
Barry Song <v-songbaohua@oppo.com> Tested-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Tested-by:
John Hubbard <jhubbard@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Rientjes <rientjes@google.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Itaru Kitayama <itaru.kitayama@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Yosry Ahmed authored
Stats flushing for memcg currently follows the following rules: - Always flush the entire memcg hierarchy (i.e. flush the root). - Only one flusher is allowed at a time. If someone else tries to flush concurrently, they skip and return immediately. - A periodic flusher flushes all the stats every 2 seconds. The reason this approach is followed is because all flushes are serialized by a global rstat spinlock. On the memcg side, flushing is invoked from userspace reads as well as in-kernel flushers (e.g. reclaim, refault, etc). This approach aims to avoid serializing all flushers on the global lock, which can cause a significant performance hit under high concurrency. This approach has the following problems: - Occasionally a userspace read of the stats of a non-root cgroup will be too expensive as it has to flush the entire hierarchy [1]. - Sometimes the stats accuracy are compromised if there is an ongoing flush, and we skip and return before the subtree of interest is actually flushed, yielding stale stats (by up to 2s due to periodic flushing). This is more visible when reading stats from userspace, but can also affect in-kernel flushers. The latter problem is particulary a concern when userspace reads stats after an event occurs, but gets stats from before the event. Examples: - When memory usage / pressure spikes, a userspace OOM handler may look at the stats of different memcgs to select a victim based on various heuristics (e.g. how much private memory will be freed by killing this). Reading stale stats from before the usage spike in this case may cause a wrongful OOM kill. - A proactive reclaimer may read the stats after writing to memory.reclaim to measure the success of the reclaim operation. Stale stats from before reclaim may give a false negative. - Reading the stats of a parent and a child memcg may be inconsistent (child larger than parent), if the flush doesn't happen when the parent is read, but happens when the child is read. As for in-kernel flushers, they will occasionally get stale stats. No regressions are currently known from this, but if there are regressions, they would be very difficult to debug and link to the source of the problem. This patch aims to fix these problems by restoring subtree flushing, and removing the unified/coalesced flushing logic that skips flushing if there is an ongoing flush. This change would introduce a significant regression with global stats flushing thresholds. With per-memcg stats flushing thresholds, this seems to perform really well. The thresholds protect the underlying lock from unnecessary contention. This patch was tested in two ways to ensure the latency of flushing is up to par, on a machine with 384 cpus: - A synthetic test with 5000 concurrent workers in 500 cgroups doing allocations and reclaim, as well as 1000 readers for memory.stat (variation of [2]). No regressions were noticed in the total runtime. Note that significant regressions in this test are observed with global stats thresholds, but not with per-memcg thresholds. - A synthetic stress test for concurrently reading memcg stats while memory allocation/freeing workers are running in the background, provided by Wei Xu [3]. With 250k threads reading the stats every 100ms in 50k cgroups, 99.9% of reads take <= 50us. Less than 0.01% of reads take more than 1ms, and no reads take more than 100ms. [1] https://lore.kernel.org/lkml/CABWYdi0c6__rh-K7dcM_pkf9BJdTRtAU08M43KO9ME4-dsgfoQ@mail.gmail.com/ [2] https://lore.kernel.org/lkml/CAJD7tka13M-zVZTyQJYL1iUAYvuQ1fcHbCjcOBZcz6POYTV-4g@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CAAPL-u9D2b=iF5Lf_cRnKxUfkiEe0AMDTu6yhrUAzX0b6a6rDg@mail.gmail.com/ [akpm@linux-foundation.org: fix mm/zswap.c] [yosryahmed@google.com: remove stats flushing mutex] Link: https://lkml.kernel.org/r/CAJD7tkZgP3m-VVPn+fF_YuvXeQYK=tZZjJHj=dzD=CcSSpp2qg@mail.gmail.com Link: https://lkml.kernel.org/r/20231129032154.3710765-6-yosryahmed@google.comSigned-off-by:
Yosry Ahmed <yosryahmed@google.com> Tested-by:
Domenico Cerasuolo <cerasuolodomenico@gmail.com> Acked-by:
Shakeel Butt <shakeelb@google.com> Cc: Chris Li <chrisl@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Wei Xu <weixugc@google.com> Signed-off-by:
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Yosry Ahmed authored
The workingset code flushes the stats in workingset_refault() to get accurate stats of the eviction memcg. In preparation for more scoped flushed and passing the eviction memcg to the flush call, move the call to workingset_test_recent() where we have a pointer to the eviction memcg. The flush call is sleepable, and cannot be made in an rcu read section. Hence, minimize the rcu read section by also moving it into workingset_test_recent(). Furthermore, instead of holding the rcu read lock throughout workingset_test_recent(), only hold it briefly to get a ref on the eviction memcg. This allows us to make the flush call after we get the eviction memcg. As for workingset_refault(), nothing else there appears to be protected by rcu. The memcg of the faulted folio (which is not necessarily the same as the eviction memcg) is protected by the folio lock, which is held from all callsites. Add a VM_BUG_ON() to make sure this doesn't change from under us. No functional change intended. Link: https://lkml.kernel.org/r/20231129032154.3710765-5-yosryahmed@google.comSigned-off-by:
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Yosry Ahmed authored
A global counter for the magnitude of memcg stats update is maintained on the memcg side to avoid invoking rstat flushes when the pending updates are not significant. This avoids unnecessary flushes, which are not very cheap even if there isn't a lot of stats to flush. It also avoids unnecessary lock contention on the underlying global rstat lock. Make this threshold per-memcg. The scheme is followed where percpu (now also per-memcg) counters are incremented in the update path, and only propagated to per-memcg atomics when they exceed a certain threshold. This provides two benefits: (a) On large machines with a lot of memcgs, the global threshold can be reached relatively fast, so guarding the underlying lock becomes less effective. Making the threshold per-memcg avoids this. (b) Having a global threshold makes it hard to do subtree flushes, as we cannot reset the global counter except for a full flush. Per-memcg counters removes this as a blocker from doing subtree flushes, which helps avoid unnecessary work when the stats of a small subtree are needed. Nothing is free, of course. This comes at a cost: (a) A new per-cpu counter per memcg, consuming NR_CPUS * NR_MEMCGS * 4 bytes. The extra memory usage is insigificant. (b) More work on the update side, although in the common case it will only be percpu counter updates. The amount of work scales with the number of ancestors (i.e. tree depth). This is not a new concept, adding a cgroup to the rstat tree involves a parent loop, so is charging. Testing results below show no significant regressions. (c) The error margin in the stats for the system as a whole increases from NR_CPUS * MEMCG_CHARGE_BATCH to NR_CPUS * MEMCG_CHARGE_BATCH * NR_MEMCGS. This is probably fine because we have a similar per-memcg error in charges coming from percpu stocks, and we have a periodic flusher that makes sure we always flush all the stats every 2s anyway. This patch was tested to make sure no significant regressions are introduced on the update path as follows. The following benchmarks were ran in a cgroup that is 2 levels deep (/sys/fs/cgroup/a/b/): (1) Running 22 instances of netperf on a 44 cpu machine with hyperthreading disabled. All instances are run in a level 2 cgroup, as well as netserver: # netserver -6 # netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Averaging 20 runs, the numbers are as follows: Base: 40198.0 mbps Patched: 38629.7 mbps (-3.9%) The regression is minimal, especially for 22 instances in the same cgroup sharing all ancestors (so updating the same atomics). (2) will-it-scale page_fault tests. These tests (specifically per_process_ops in page_fault3 test) detected a 25.9% regression before for a change in the stats update path [1]. These are the numbers from 10 runs (+ is good) on a machine with 256 cpus: LABEL | MEAN | MEDIAN | STDDEV | ------------------------------+-------------+-------------+------------- page_fault1_per_process_ops | | | | (A) base | 270249.164 | 265437.000 | 13451.836 | (B) patched | 261368.709 | 255725.000 | 13394.767 | | -3.29% | -3.66% | | page_fault1_per_thread_ops | | | | (A) base | 242111.345 | 239737.000 | 10026.031 | (B) patched | 237057.109 | 235305.000 | 9769.687 | | -2.09% | -1.85% | | page_fault1_scalability | | | (A) base | 0.034387 | 0.035168 | 0.0018283 | (B) patched | 0.033988 | 0.034573 | 0.0018056 | | -1.16% | -1.69% | | page_fault2_per_process_ops | | | (A) base | 203561.836 | 203301.000 | 2550.764 | (B) patched | 197195.945 | 197746.000 | 2264.263 | | -3.13% | -2.73% | | page_fault2_per_thread_ops | | | (A) base | 171046.473 | 170776.000 | 1509.679 | (B) patched | 166626.327 | 166406.000 | 768.753 | | -2.58% | -2.56% | | page_fault2_scalability | | | (A) base | 0.054026 | 0.053821 | 0.00062121 | (B) patched | 0.053329 | 0.05306 | 0.00048394 | | -1.29% | -1.41% | | page_fault3_per_process_ops | | | (A) base | 1295807.782 | 1297550.000 | 5907.585 | (B) patched | 1275579.873 | 1273359.000 | 8759.160 | | -1.56% | -1.86% | | page_fault3_per_thread_ops | | | (A) base | 391234.164 | 390860.000 | 1760.720 | (B) patched | 377231.273 | 376369.000 | 1874.971 | | -3.58% | -3.71% | | page_fault3_scalability | | | (A) base | 0.60369 | 0.60072 | 0.0083029 | (B) patched | 0.61733 | 0.61544 | 0.009855 | | +2.26% | +2.45% | | All regressions seem to be minimal, and within the normal variance for the benchmark. The fix for [1] assumes that 3% is noise -- and there were no further practical complaints), so hopefully this means that such variations in these microbenchmarks do not reflect on practical workloads. (3) I also ran stress-ng in a nested cgroup and did not observe any obvious regressions. [1]https://lore.kernel.org/all/20190520063534.GB19312@shao2-debian/ Link: https://lkml.kernel.org/r/20231129032154.3710765-4-yosryahmed@google.comSigned-off-by:Johannes Weiner <hannes@cmpxchg.org> Tested-by:
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Yosry Ahmed authored
The following patch will make use of those structs in the flushing code, so move their definitions (and a few other dependencies) a little bit up to reduce the diff noise in the following patch. No functional change intended. Link: https://lkml.kernel.org/r/20231129032154.3710765-3-yosryahmed@google.comSigned-off-by:
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Yosry Ahmed authored
Patch series "mm: memcg: subtree stats flushing and thresholds", v4. This series attempts to address shortages in today's approach for memcg stats flushing, namely occasionally stale or expensive stat reads. The series does so by changing the threshold that we use to decide whether to trigger a flush to be per memcg instead of global (patch 3), and then changing flushing to be per memcg (i.e. subtree flushes) instead of global (patch 5). This patch (of 5): flush_next_time is an inaccurate name. It's not the next time that periodic flushing will happen, it's rather the next time that ratelimited flushing can happen if the periodic flusher is late. Simplify its semantics by just storing the timestamp of the last flush instead, flush_last_time. Move the 2*FLUSH_TIME addition to mem_cgroup_flush_stats_ratelimited(), and add a comment explaining it. This way, all the ratelimiting semantics live in one place. No functional change intended. Link: https://lkml.kernel.org/r/20231129032154.3710765-1-yosryahmed@google.com Link: https://lkml.kernel.org/r/20231129032154.3710765-2-yosryahmed@google.comSigned-off-by:
Bagas Sanjaya <bagasdotme@gmail.com> Cc: Greg Thelen <gthelen@google.com> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Wei Xu <weixugc@google.com> Signed-off-by:
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Andrew Morton authored
Fixes: 0a97c01c ("list_lru: allow explicit memcg and NUMA node selection) Reported-by:
kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202312141318.q8b5yrAq-lkp@intel.com/ Cc: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by:
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Andrew Morton authored
Commit 0de56e38 ("maple_tree: use maple state end for write operations") was broken by a later patch "maple_tree: do not preallocate nodes for slot stores". But the later patch was scheduled ahead of 0de56e38, for 6.7-rc. This fixlet undoes the damage. Fixes: 0de56e38 ("maple_tree: use maple state end for write operations") Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by:
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Andrew Morton authored
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Matthew Wilcox (Oracle) authored
This address now bounces, remap it to a current address. Link: https://lkml.kernel.org/r/20231218140328.3313474-1-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
On 32-bit systems, we'll lose the top bits of index because arithmetic will be performed in unsigned long instead of unsigned long long. This affects files over 4GB in size. Link: https://lkml.kernel.org/r/20231218135837.3310403-4-willy@infradead.org Fixes: 6100e34b ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages") Signed-off-by:
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Matthew Wilcox (Oracle) authored
A process may map only some of the pages in a folio, and might be missed if it maps the poisoned page but not the head page. Or it might be unnecessarily hit if it maps the head page, but not the poisoned page. Link: https://lkml.kernel.org/r/20231218135837.3310403-3-willy@infradead.org Fixes: 7af446a8 ("HWPOISON, hugetlb: enable error handling path for hugepage") Signed-off-by:
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Matthew Wilcox (Oracle) authored
Patch series "Three memory-failure fixes". I've been looking at the memory-failure code and I believe I have found three bugs that need fixing -- one going all the way back to 2010! I'll have more patches later to use folios more extensively but didn't want these bugfixes to get caught up in that. This patch (of 3): Both collect_procs_anon() and collect_procs_file() iterate over the VMA interval trees looking for a single pgoff, so it is wrong to look for the pgoff of the head page as is currently done. However, it is also wrong to look at page->mapping of the precise page as this is invalid for tail pages. Clear up the confusion by passing both the folio and the precise page to collect_procs(). Link: https://lkml.kernel.org/r/20231218135837.3310403-1-willy@infradead.org Link: https://lkml.kernel.org/r/20231218135837.3310403-2-willy@infradead.org Fixes: 415c64c1 ("mm/memory-failure: split thp earlier in memory error handling") Signed-off-by:
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Muhammad Usama Anjum authored
The "locked-in-memory size" limit per process can be non-multiple of page_size. The mmap() fails if we try to allocate locked-in-memory with same size as the allowed limit if it isn't multiple of the page_size because mmap() rounds off the memory size to be allocated to next multiple of page_size. Fix this by flooring the length to be allocated with mmap() to the previous multiple of the page_size. This was getting triggered on KernelCI regularly because of different ulimit settings which wasn't multiple of the page_size. Find logs here: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/ The bug in was present from the time test was first added. Link: https://lkml.kernel.org/r/20231214101931.1155586-1-usama.anjum@collabora.com Fixes: 76fe17ef ("secretmem: test: add basic selftest for memfd_secret(2)") Signed-off-by:
Muhammad Usama Anjum <usama.anjum@collabora.com> Reported-by:
"kernelci.org bot" <bot@kernelci.org> Closes: https://linux.kernelci.org/test/plan/id/657654bd8e81e654fae13532/ Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by:
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Charan Teja Kalla authored
Large folios occupy N consecutive entries in the swap cache instead of using multi-index entries like the page cache. However, if a large folio is re-added to the LRU list, it can be migrated. The migration code was not aware of the difference between the swap cache and the page cache and assumed that a single xas_store() would be sufficient. This leaves potentially many stale pointers to the now-migrated folio in the swap cache, which can lead to almost arbitrary data corruption in the future. This can also manifest as infinite loops with the RCU read lock held. [willy@infradead.org: modifications to the changelog & tweaked the fix] Fixes: 3417013e ("mm/migrate: Add folio_migrate_mapping()") Link: https://lkml.kernel.org/r/20231214045841.961776-1-willy@infradead.orgSigned-off-by:
Charan Teja Kalla <quic_charante@quicinc.com> Signed-off-by:
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Sidhartha Kumar authored
mas_preallocate() defaults to requesting 1 node for preallocation and then ,depending on the type of store, will update the request variable. There isn't a check for a slot store type, so slot stores are preallocating the default 1 node. Slot stores do not require any additional nodes, so add a check for the slot store case that will bypass node_count_gfp(). Update the tests to reflect that slot stores do not require allocations. User visible effects of this bug include increased memory usage from the unneeded node that was allocated. Link: https://lkml.kernel.org/r/20231213205058.386589-1-sidhartha.kumar@oracle.com Fixes: 0b8bb544 ("maple_tree: update mas_preallocate() testing") Signed-off-by:
Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: <stable@vger.kernel.org> [6.6+] Signed-off-by:
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Baokun Li authored
The following concurrency may cause the data read to be inconsistent with the data on disk: cpu1 cpu2 ------------------------------|------------------------------ // Buffered write 2048 from 0 ext4_buffered_write_iter generic_perform_write copy_page_from_iter_atomic ext4_da_write_end ext4_da_do_write_end block_write_end __block_commit_write folio_mark_uptodate // Buffered read 4096 from 0 smp_wmb() ext4_file_read_iter set_bit(PG_uptodate, folio_flags) generic_file_read_iter i_size_write // 2048 filemap_read unlock_page(page) filemap_get_pages filemap_get_read_batch folio_test_uptodate(folio) ret = test_bit(PG_uptodate, folio_flags) if (ret) smp_rmb(); // Ensure that the data in page 0-2048 is up-to-date. // New buffered write 2048 from 2048 ext4_buffered_write_iter generic_perform_write copy_page_from_iter_atomic ext4_da_write_end ext4_da_do_write_end block_write_end __block_commit_write folio_mark_uptodate smp_wmb() set_bit(PG_uptodate, folio_flags) i_size_write // 4096 unlock_page(page) isize = i_size_read(inode) // 4096 // Read the latest isize 4096, but without smp_rmb(), there may be // Load-Load disorder resulting in the data in the 2048-4096 range // in the page is not up-to-date. copy_page_to_iter // copyout 4096 In the concurrency above, we read the updated i_size, but there is no read barrier to ensure that the data in the page is the same as the i_size at this point, so we may copy the unsynchronized page out. Hence adding the missing read memory barrier to fix this. This is a Load-Load reordering issue, which only occurs on some weak mem-ordering architectures (e.g. ARM64, ALPHA), but not on strong mem-ordering architectures (e.g. X86). And theoretically the problem doesn't only happen on ext4, filesystems that call filemap_read() but don't hold inode lock (e.g. btrfs, f2fs, ubifs ...) will have this problem, while filesystems with inode lock (e.g. xfs, nfs) won't have this problem. Link: https://lkml.kernel.org/r/20231213062324.739009-1-libaokun1@huawei.comSigned-off-by:Baokun Li <libaokun1@huawei.com> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: yangerkun <yangerkun@huawei.com> Cc: Yu Kuai <yukuai3@huawei.com> Cc: Zhang Yi <yi.zhang@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Nico Pache authored
Similar to commit 09c6304e ("kasan: test: fix compatibility with FORTIFY_SOURCE") the kernel is panicing in kmalloc_oob_memset_*. This is due to the `ptr` not being hidden from the optimizer which would disable the runtime fortify string checker. kernel BUG at lib/string_helpers.c:1048! Call Trace: [<00000000272502e2>] fortify_panic+0x2a/0x30 ([<00000000272502de>] fortify_panic+0x26/0x30) [<001bffff817045c4>] kmalloc_oob_memset_2+0x22c/0x230 [kasan_test] Hide the `ptr` variable from the optimizer to fix the kernel panic. Also define a memset_size variable and hide that as well. This cleans up the code and follows the same convention as other tests. [npache@redhat.com: address review comments from Andrey] Link: https://lkml.kernel.org/r/20231214164423.6202-1-npache@redhat.com Link: https://lkml.kernel.org/r/20231212232659.18839-1-npache@redhat.comSigned-off-by:
Nico Pache <npache@redhat.com> Reviewed-by:
Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by:
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Arnd Bergmann authored
All other users of crypto code use 'select' instead of 'depends on', so do the same thing with KEXEC_FILE for consistency. In practice this makes very little difference as kernels with kexec support are very likely to also include some other feature that already selects both crypto and crypto_sha256, but being consistent here helps for usability as well as to avoid potential circular dependencies. This reverts the dependency back to what it was originally before commit 74ca317c ("kexec: create a new config option CONFIG_KEXEC_FILE for new syscall"), which changed changed it with the comment "This should be safer as "select" is not recursive", but that appears to have been done in error, as "select" is indeed recursive, and there are no other dependencies that prevent CRYPTO_SHA256 from being selected here. Link: https://lkml.kernel.org/r/20231023110308.1202042-2-arnd@kernel.org Fixes: 74ca317c ("kexec: create a new config option CONFIG_KEXEC_FILE for new syscall") Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Reviewed-by:
Eric DeVolder <eric_devolder@yahoo.com> Tested-by:
Baoquan He <bhe@redhat.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: "David S. Miller" <davem@davemloft.net> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Conor Dooley <conor@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by:
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Arnd Bergmann authored
The cleanup for the CONFIG_KEXEC Kconfig logic accidentally changed the 'depends on CRYPTO=y' dependency to a plain 'depends on CRYPTO', which causes a link failure when all the crypto support is in a loadable module and kexec_file support is built-in: x86_64-linux-ld: vmlinux.o: in function `__x64_sys_kexec_file_load': (.text+0x32e30a): undefined reference to `crypto_alloc_shash' x86_64-linux-ld: (.text+0x32e58e): undefined reference to `crypto_shash_update' x86_64-linux-ld: (.text+0x32e6ee): undefined reference to `crypto_shash_final' Both s390 and x86 have this problem, while ppc64 and riscv have the correct dependency already. On riscv, the dependency is only used for the purgatory, not for the kexec_file code itself, which may be a bit surprising as it means that with CONFIG_CRYPTO=m, it is possible to enable KEXEC_FILE but then the purgatory code is silently left out. Move this into the common Kconfig.kexec file in a way that is correct everywhere, using the dependency on CRYPTO_SHA256=y only when the purgatory code is available. This requires reversing the dependency between ARCH_SUPPORTS_KEXEC_PURGATORY and KEXEC_FILE, but the effect remains the same, other than making riscv behave like the other ones. On s390, there is an additional dependency on CRYPTO_SHA256_S390, which should technically not be required but gives better performance. Remove this dependency here, noting that it was not present in the initial Kconfig code but was brought in without an explanation in commit 71406883 ("s390/kexec_file: Add kexec_file_load system call"). [arnd@arndb.de: fix riscv build] Link: https://lkml.kernel.org/r/67ddd260-d424-4229-a815-e3fcfb864a77@app.fastmail.com Link: https://lkml.kernel.org/r/20231023110308.1202042-1-arnd@kernel.org Fixes: 6af51380 ("x86/kexec: refactor for kernel/Kconfig.kexec") Signed-off-by:
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- 13 Dec, 2023 17 commits
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Yu Zhao authored
In the effort to reduce zombie memcgs [1], it was discovered that the memcg LRU doesn't apply enough pressure on offlined memcgs. Specifically, instead of rotating them to the tail of the current generation (MEMCG_LRU_TAIL) for a second attempt, it moves them to the next generation (MEMCG_LRU_YOUNG) after the first attempt. Not applying enough pressure on offlined memcgs can cause them to build up, and this can be particularly harmful to memory-constrained systems. On Pixel 8 Pro, launching apps for 50 cycles: Before After Change Zombie memcgs 45 35 -22% [1] https://lore.kernel.org/CABdmKX2M6koq4Q0Cmp_-=wbP0Qa190HdEGGaHfxNS05gAkUtPA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20231208061407.2125867-4-yuzhao@google.com Fixes: e4dde56c ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by:T.J. Mercier <tjmercier@google.com> Tested-by:
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Yu Zhao authored
While investigating kswapd "consuming 100% CPU" [1] (also see "mm/mglru: try to stop at high watermarks"), it was discovered that the memcg LRU can breach the thrashing protection imposed by min_ttl_ms. Before the memcg LRU: kswapd() shrink_node_memcgs() mem_cgroup_iter() inc_max_seq() // always hit a different memcg lru_gen_age_node() mem_cgroup_iter() check the timestamp of the oldest generation After the memcg LRU: kswapd() shrink_many() restart: iterate the memcg LRU: inc_max_seq() // occasionally hit the same memcg if raced with lru_gen_rotate_memcg(): goto restart lru_gen_age_node() mem_cgroup_iter() check the timestamp of the oldest generation Specifically, when the restart happens in shrink_many(), it needs to stick with the (memcg LRU) generation it began with. In other words, it should neither re-read memcg_lru->seq nor age an lruvec of a different generation. Otherwise it can hit the same memcg multiple times without giving lru_gen_age_node() a chance to check the timestamp of that memcg's oldest generation (against min_ttl_ms). [1] https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/ Link: https://lkml.kernel.org/r/20231208061407.2125867-3-yuzhao@google.com Fixes: e4dde56c ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: -
Yu Zhao authored
The initial MGLRU patchset didn't include the memcg LRU support, and it relied on should_abort_scan(), added by commit f76c8337 ("mm: multi-gen LRU: optimize multiple memcgs"), to "backoff to avoid overshooting their aggregate reclaim target by too much". Later on when the memcg LRU was added, should_abort_scan() was deemed unnecessary, and the test results [1] showed no side effects after it was removed by commit a579086c ("mm: multi-gen LRU: remove eviction fairness safeguard"). However, that test used memory.reclaim, which sets nr_to_reclaim to SWAP_CLUSTER_MAX. So it can overshoot only by SWAP_CLUSTER_MAX-1 pages, i.e., from nr_reclaimed=nr_to_reclaim-1 to nr_reclaimed=nr_to_reclaim+SWAP_CLUSTER_MAX-1. Compared with the batch size kswapd sets to nr_to_reclaim, SWAP_CLUSTER_MAX is tiny. Therefore that test isn't able to reproduce the worst case scenario, i.e., kswapd overshooting GBs on large systems and "consuming 100% CPU" (see the Closes tag). Bring back a simplified version of should_abort_scan() on top of the memcg LRU, so that kswapd stops when all eligible zones are above their respective high watermarks plus a small delta to lower the chance of KSWAPD_HIGH_WMARK_HIT_QUICKLY. Note that this only applies to order-0 reclaim, meaning compaction-induced reclaim can still run wild (which is a different problem). On Android, launching 55 apps sequentially: Before After Change pgpgin 838377172 802955040 -4% pgpgout 38037080 34336300 -10% [1] https://lore.kernel.org/20221222041905.2431096-1-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20231208061407.2125867-2-yuzhao@google.com Fixes: a579086c ("mm: multi-gen LRU: remove eviction fairness safeguard") Signed-off-by:
Jaroslav Pulchart <jaroslav.pulchart@gooddata.com> Closes: https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/Tested-by:
Kalesh Singh <kaleshsingh@google.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Kairui Song <ryncsn@gmail.com> Cc: T.J. Mercier <tjmercier@google.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Yu Zhao authored
Unmapped folios accessed through file descriptors can be underprotected. Those folios are added to the oldest generation based on: 1. The fact that they are less costly to reclaim (no need to walk the rmap and flush the TLB) and have less impact on performance (don't cause major PFs and can be non-blocking if needed again). 2. The observation that they are likely to be single-use. E.g., for client use cases like Android, its apps parse configuration files and store the data in heap (anon); for server use cases like MySQL, it reads from InnoDB files and holds the cached data for tables in buffer pools (anon). However, the oldest generation can be very short lived, and if so, it doesn't provide the PID controller with enough time to respond to a surge of refaults. (Note that the PID controller uses weighted refaults and those from evicted generations only take a half of the whole weight.) In other words, for a short lived generation, the moving average smooths out the spike quickly. To fix the problem: 1. For folios that are already on LRU, if they can be beyond the tracking range of tiers, i.e., five accesses through file descriptors, move them to the second oldest generation to give them more time to age. (Note that tiers are used by the PID controller to statistically determine whether folios accessed multiple times through file descriptors are worth protecting.) 2. When adding unmapped folios to LRU, adjust the placement of them so that they are not too close to the tail. The effect of this is similar to the above. On Android, launching 55 apps sequentially: Before After Change workingset_refault_anon 25641024 25598972 0% workingset_refault_file 115016834 106178438 -8% Link: https://lkml.kernel.org/r/20231208061407.2125867-1-yuzhao@google.com Fixes: ac35a490 ("mm: multi-gen LRU: minimal implementation") Signed-off-by: -
David Stevens authored
Split folios during the second loop of shmem_undo_range. It's not sufficient to only split folios when dealing with partial pages, since it's possible for a THP to be faulted in after that point. Calling truncate_inode_folio in that situation can result in throwing away data outside of the range being targeted. [akpm@linux-foundation.org: tidy up comment layout] Link: https://lkml.kernel.org/r/20230418084031.3439795-1-stevensd@google.com Fixes: b9a8a419 ("truncate,shmem: Handle truncates that split large folios") Signed-off-by:
David Stevens <stevensd@chromium.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Suleiman Souhlal <suleiman@google.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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John Hubbard authored
This reverts commit 9fc96c7c ("selftests: error out if kernel header files are not yet built"). It turns out that requiring the kernel headers to be built as a prerequisite to building selftests, does not work in many cases. For example, Peter Zijlstra writes: "My biggest beef with the whole thing is that I simply do not want to use 'make headers', it doesn't work for me. I have a ton of output directories and I don't care to build tools into the output dirs, in fact some of them flat out refuse to work that way (bpf comes to mind)." [1] Therefore, stop erroring out on the selftests build. Additional patches will be required in order to change over to not requiring the kernel headers. [1] https://lore.kernel.org/20231208221007.GO28727@noisy.programming.kicks-ass.net Link: https://lkml.kernel.org/r/20231209020144.244759-1-jhubbard@nvidia.com Fixes: 9fc96c7c ("selftests: error out if kernel header files are not yet built") Signed-off-by:
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Yuntao Wang authored
If crash_base is equal to CRASH_ADDR_LOW_MAX, it also indicates that the crashkernel memory is allocated from high memory. However, the current check only considers the case where crash_base is greater than CRASH_ADDR_LOW_MAX. Fix it. The runtime effects is that crashkernel high memory is successfully reserved, whereas the crashkernel low memory is bypassed in this case, then kdump kernel bootup will fail because of no low memory under 4G. This patch also includes some minor cleanups. Link: https://lkml.kernel.org/r/20231209141438.77233-1-ytcoode@gmail.com Fixes: 0ab97169 ("crash_core: add generic function to do reservation") Signed-off-by:
Yuntao Wang <ytcoode@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Zhen Lei <thunder.leizhen@huawei.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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Baoquan He authored
With the current ifdeffery CONFIG_KEXEC, get_cmdline_acpi_rsdp() is only available when kexec_load interface is taken, while kexec_file_load interface can't make use of it. Now change it to CONFIG_KEXEC_CORE. Link: https://lkml.kernel.org/r/20231208073036.7884-6-bhe@redhat.comSigned-off-by:
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Baoquan He authored
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === Here, change the dependency of building kexec_core related object files, and the ifdeffery on SuperH from CONFIG_KEXEC to CONFIG_KEXEC_CORE. Link: https://lkml.kernel.org/r/20231208073036.7884-5-bhe@redhat.comSigned-off-by:
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Baoquan He authored
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === -------------------------------------------------------------------- mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free': kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup' mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec': kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec' mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec': kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec' -------------------------------------------------------------------- Here, change the dependency of building kexec_core related object files, and the ifdeffery in mips from CONFIG_KEXEC to CONFIG_KEXEC_CORE. Link: https://lkml.kernel.org/r/20231208073036.7884-4-bhe@redhat.comSigned-off-by:
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Baoquan He authored
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === Here, change the dependency of buinding machine_kexec.o relocate_kernel.o and the ifdeffery in asm/kexe.h to CONFIG_KEXEC_CORE. Link: https://lkml.kernel.org/r/20231208073036.7884-3-bhe@redhat.comSigned-off-by:
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Baoquan He authored
Patch series "kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC". The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === E.g on mips, below link error are seen: -------------------------------------------------------------------- mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free': kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup' mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec': kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec' mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec': kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec' -------------------------------------------------------------------- Here, change the incorrect dependency of building kexec_core related object files, and the ifdeffery on architectures from CONFIG_KEXEC to CONFIG_KEXEC_CORE. Testing: ======== Passed on mips and loognarch with the LKP reproducer. This patch (of 5): Currently, in arch/loongarch/kernel/Makefile, building machine_kexec.o relocate_kernel.o depends on CONFIG_KEXEC. Whereas, since we will drop the select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec, compiling error will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === --------------------------------------------------------------- loongarch64-linux-ld: kernel/kexec_core.o: in function `.L209': >> kexec_core.c:(.text+0x1660): undefined reference to `machine_kexec_cleanup' loongarch64-linux-ld: kernel/kexec_core.o: in function `.L287': >> kexec_core.c:(.text+0x1c5c): undefined reference to `machine_crash_shutdown' >> loongarch64-linux-ld: kexec_core.c:(.text+0x1c64): undefined reference to `machine_kexec' loongarch64-linux-ld: kernel/kexec_core.o: in function `.L2^B5': >> kexec_core.c:(.text+0x2090): undefined reference to `machine_shutdown' loongarch64-linux-ld: kexec_core.c:(.text+0x20a0): undefined reference to `machine_kexec' --------------------------------------------------------------- Here, change the dependency of machine_kexec.o relocate_kernel.o to CONFIG_KEXEC_CORE can fix above building error. Link: https://lkml.kernel.org/r/20231208073036.7884-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20231208073036.7884-2-bhe@redhat.comSigned-off-by:
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SeongJae Park authored
The cleanup tasks of kdamond threads including reset of corresponding DAMON context's ->kdamond field and decrease of global nr_running_ctxs counter is supposed to be executed by kdamond_fn(). However, commit 0f91d133 ("mm/damon: simplify stop mechanism") made neither damon_start() nor damon_stop() ensure the corresponding kdamond has started the execution of kdamond_fn(). As a result, the cleanup can be skipped if damon_stop() is called fast enough after the previous damon_start(). Especially the skipped reset of ->kdamond could cause a use-after-free. Fix it by waiting for start of kdamond_fn() execution from damon_start(). Link: https://lkml.kernel.org/r/20231208175018.63880-1-sj@kernel.org Fixes: 0f91d133 ("mm/damon: simplify stop mechanism") Signed-off-by:
SeongJae Park <sj@kernel.org> Reported-by:
Jakub Acs <acsjakub@amazon.de> Cc: Changbin Du <changbin.du@intel.com> Cc: Jakub Acs <acsjakub@amazon.de> Cc: <stable@vger.kernel.org> # 5.15.x Signed-off-by:
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David Hildenbrand authored
Doing a ksft_print_msg() before the ksft_print_header() seems to confuse the ksft framework in a strange way: running the test on the cmdline results in the expected output. But piping the output somewhere else, results in some odd output, whereby we repeatedly get the same info printed: # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled TAP version 13 1..190 # [INFO] Anonymous memory tests in private mappings # [RUN] Basic COW after fork() ... with base page # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled TAP version 13 1..190 # [INFO] Anonymous memory tests in private mappings # [RUN] Basic COW after fork() ... with base page ok 1 No leak from parent into child # [RUN] Basic COW after fork() ... with swapped out base page # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled Doing the ksft_print_header() first seems to resolve that and gives us the output we expect: TAP version 13 # [INFO] detected THP size: 2048 KiB # [INFO] detected hugetlb page size: 2048 KiB # [INFO] detected hugetlb page size: 1048576 KiB # [INFO] huge zeropage is enabled 1..190 # [INFO] Anonymous memory tests in private mappings # [RUN] Basic COW after fork() ... with base page ok 1 No leak from parent into child # [RUN] Basic COW after fork() ... with swapped out base page ok 2 No leak from parent into child # [RUN] Basic COW after fork() ... with THP ok 3 No leak from parent into child # [RUN] Basic COW after fork() ... with swapped-out THP ok 4 No leak from parent into child # [RUN] Basic COW after fork() ... with PTE-mapped THP ok 5 No leak from parent into child Link: https://lkml.kernel.org/r/20231206103558.38040-1-david@redhat.com Fixes: f4b5fd69 ("selftests/vm: anon_cow: THP tests") Signed-off-by:
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Kefeng Wang authored
After converting selinux to VMA heap check helper, the gcl triggers an execheap SELinux denial, which is caused by a changed logic check. Previously selinux only checked that the VMA range was within the VMA heap range, and the implementation checks the intersection between the two ranges, but the corner case (vm_end=start_brk, brk=vm_start) isn't handled correctly. Since commit 11250fd1 ("mm: factor out VMA stack and heap checks") was only a function extraction, it seems that the issue was introduced by commit 0db0c01b ("procfs: fix /proc/<pid>/maps heap check"). Let's fix above corner cases, meanwhile, correct the wrong indentation of the stack and heap check helpers. Fixes: 11250fd1 ("mm: factor out VMA stack and heap checks") Signed-off-by:
Ondrej Mosnacek <omosnace@redhat.com> Closes: https://lore.kernel.org/selinux/CAFqZXNv0SVT0fkOK6neP9AXbj3nxJ61JAY4+zJzvxqJaeuhbFw@mail.gmail.com/Tested-by:
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Baoquan He authored
When below config items are set, compiler complained: -------------------- CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y ...... ----------------------- ------------------------------------------------------------------- arch/riscv/kernel/crash_core.c: In function 'arch_crash_save_vmcoreinfo': arch/riscv/kernel/crash_core.c:11:58: warning: format '%lx' expects argument of type 'long unsigned int', but argument 2 has type 'int' [-Wformat=] 11 | vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START); | ~~^ | | | long unsigned int | %x ---------------------------------------------------------------------- This is because on riscv macro VMALLOC_START has different type when CONFIG_MMU is set or unset. arch/riscv/include/asm/pgtable.h: -------------------------------------------------- Changing it to _AC(0, UL) in case CONFIG_MMU=n can fix the warning. Link: https://lkml.kernel.org/r/ZW7OsX4zQRA3mO4+@MiWiFi-R3L-srvSigned-off-by:Randy Dunlap <rdunlap@infradead.org> Acked-by:
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Ignat Korchagin authored
In commit f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP") we tried to fix a config regression, where CONFIG_CRASH_DUMP required CONFIG_KEXEC. However, it was not enough at least for arm64 platforms. While further testing the patch with our arm64 config I noticed that CONFIG_CRASH_DUMP is unavailable in menuconfig. This is because CONFIG_CRASH_DUMP still depends on the new CONFIG_ARCH_SUPPORTS_KEXEC introduced in commit 91506f7e ("arm64/kexec: refactor for kernel/Kconfig.kexec") and on arm64 CONFIG_ARCH_SUPPORTS_KEXEC requires CONFIG_PM_SLEEP_SMP=y, which in turn requires either CONFIG_SUSPEND=y or CONFIG_HIBERNATION=y neither of which are set in our config. Given that we already established that CONFIG_KEXEC (which is a switch for kexec system call itself) is not required for CONFIG_CRASH_DUMP drop CONFIG_ARCH_SUPPORTS_KEXEC dependency as well. The arm64 kernel builds just fine with CONFIG_CRASH_DUMP=y and with both CONFIG_KEXEC=n and CONFIG_KEXEC_FILE=n after f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP") and this patch are applied given that the necessary shared bits are included via CONFIG_KEXEC_CORE dependency. [bhe@redhat.com: don't export some symbols when CONFIG_MMU=n] Link: https://lkml.kernel.org/r/ZW03ODUKGGhP1ZGU@MiWiFi-R3L-srv [bhe@redhat.com: riscv, kexec: fix dependency of two items] Link: https://lkml.kernel.org/r/ZW04G/SKnhbE5mnX@MiWiFi-R3L-srv Link: https://lkml.kernel.org/r/20231129220409.55006-1-ignat@cloudflare.com Fixes: 91506f7e ("arm64/kexec: refactor for kernel/Kconfig.kexec") Signed-off-by:Ignat Korchagin <ignat@cloudflare.com> Signed-off-by:
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- 12 Dec, 2023 3 commits
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Levi Yun authored
mas_split_final_node() always returns true and its return value is never checked. Change return type to void. Link: https://lkml.kernel.org/r/20231109160821.16248-2-ppbuk5246@gmail.comSigned-off-by:
Levi Yun <ppbuk5246@gmail.com> Reviewed-by:
Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by:
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Barry Song authored
Testing shows fast_isolate_freepages can blindly choose an unsuitable pageblock from time to time particularly while the min mark is used from XXX path: if (!page) { cc->fast_search_fail++; if (scan_start) { /* * Use the highest PFN found above min. If one was * not found, be pessimistic for direct compaction * and use the min mark. */ if (highest >= min_pfn) { page = pfn_to_page(highest); cc->free_pfn = highest; } else { if (cc->direct_compaction && pfn_valid(min_pfn)) { /* XXX */ page = pageblock_pfn_to_page(min_pfn, min(pageblock_end_pfn(min_pfn), zone_end_pfn(cc->zone)), cc->zone); cc->free_pfn = min_pfn; } } } } The reason is that no code is doing any check on the min_pfn min_pfn = pageblock_start_pfn(cc->free_pfn - (distance >> 1)); In contrast, slow path of isolate_freepages() is always skipping unsuitable pageblocks in a decent way. This issue doesn't happen quite often. When running 25 machines with 16GiB memory for one night, most of them can hit this unexpected code path. However the frequency isn't like many times per second. It might be one time in a couple of hours. Thus, it is very hard to measure the visible performance impact in my machines though the affection of choosing the unsuitable migration_target should be negative in theory. I feel it's still worth fixing this to at least make the code theoretically self-explanatory as it is quite odd an unsuitable migration_target can be still migration_target. Link: https://lkml.kernel.org/r/20231206110054.61617-1-v-songbaohua@oppo.comSigned-off-by:Zhanyuan Hu <huzhanyuan@oppo.com> Reviewed-by:
Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by:
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Chen Haonan authored
vma_pages() is more readable and also better at avoiding error codes, so use vma_pages() instead of direct operations on vma Link: https://lkml.kernel.org/r/tencent_151850CF327EB055BBC83298A929BD06CD0A@qq.comSigned-off-by:
Chen Haonan <chen.haonan2@zte.com.cn> Signed-off-by:
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