- 09 Sep, 2024 9 commits
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Kefeng Wang authored
Saves a couple of calls to compound_head() and remove last two callers of putback_lru_page(). Link: https://lkml.kernel.org/r/20240826065814.1336616-5-wangkefeng.wang@huawei.comSigned-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by:
Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by:
Alistair Popple <apopple@nvidia.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Kefeng Wang authored
The page for migrate_device_unmap() already has a reference, so it is safe to convert the page to folio to save a few calls to compound_head(), which removes the last isolate_lru_page() call. Link: https://lkml.kernel.org/r/20240826065814.1336616-4-wangkefeng.wang@huawei.comSigned-off-by:
David Hildenbrand <david@redhat.com> Reviewed-by:
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Kefeng Wang authored
Save two calls to compound_head() and use folio throughout. Link: https://lkml.kernel.org/r/20240826065814.1336616-3-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Patch series "mm: finish isolate/putback_lru_page()". Convert to use more folios in migrate_device.c, then we could remove isolate_lru_page() and putback_lru_page(). This patch (of 6): Save a few calls to compound_head() and use folio throughout. Link: https://lkml.kernel.org/r/20240826065814.1336616-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240826065814.1336616-2-wangkefeng.wang@huawei.comSigned-off-by:
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Matthew Wilcox (Oracle) authored
Retrieve a folio from the page cache rather than a page. Saves a couple of conversions between page & folio. Link: https://lkml.kernel.org/r/20240826202138.3804238-1-willy@infradead.orgSigned-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
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Barry Song authored
When a THP is added to the deferred_list due to partially mapped, its partial pages are unused, leading to wasted memory and potentially increasing memory reclamation pressure. Detailing the specifics of how unmapping occurs is quite difficult and not that useful, so we adopt a simple approach: each time a THP enters the deferred_list, we increment the count by 1; whenever it leaves for any reason, we decrement the count by 1. Link: https://lkml.kernel.org/r/20240824010441.21308-3-21cnbao@gmail.comSigned-off-by:
Barry Song <v-songbaohua@oppo.com> Acked-by:
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Barry Song authored
Patch series "mm: count the number of anonymous THPs per size", v4. Knowing the number of transparent anon THPs in the system is crucial for performance analysis. It helps in understanding the ratio and distribution of THPs versus small folios throughout the system. Additionally, partial unmapping by userspace can lead to significant waste of THPs over time and increase memory reclamation pressure. We need this information for comprehensive system tuning. This patch (of 2): Let's track for each anonymous THP size, how many of them are currently allocated. We'll track the complete lifespan of an anon THP, starting when it becomes an anon THP ("large anon folio") (->mapping gets set), until it gets freed (->mapping gets cleared). Introduce a new "nr_anon" counter per THP size and adjust the corresponding counter in the following cases: * We allocate a new THP and call folio_add_new_anon_rmap() to map it the first time and turn it into an anon THP. * We split an anon THP into multiple smaller ones. * We migrate an anon THP, when we prepare the destination. * We free an anon THP back to the buddy. Note that AnonPages in /proc/meminfo currently tracks the total number of *mapped* anonymous *pages*, and therefore has slightly different semantics. In the future, we might also want to track "nr_anon_mapped" for each THP size, which might be helpful when comparing it to the number of allocated anon THPs (long-term pinning, stuck in swapcache, memory leaks, ...). Further note that for now, we only track anon THPs after they got their ->mapping set, for example via folio_add_new_anon_rmap(). If we would allocate some in the swapcache, they will only show up in the statistics for now after they have been mapped to user space the first time, where we call folio_add_new_anon_rmap(). [akpm@linux-foundation.org: documentation fixups, per David] Link: https://lkml.kernel.org/r/3e8add35-e26b-443b-8a04-1078f4bc78f6@redhat.com Link: https://lkml.kernel.org/r/20240824010441.21308-1-21cnbao@gmail.com Link: https://lkml.kernel.org/r/20240824010441.21308-2-21cnbao@gmail.comSigned-off-by: -
Ryan Roberts authored
Previously we had a situation where shmem mTHP controls and stats were not exposed for some supported sizes and were exposed for some unsupported sizes. So let's clean that up. Anon mTHP can support all large orders [2, PMD_ORDER]. But shmem can support all large orders [1, MAX_PAGECACHE_ORDER]. However, per-size shmem controls and stats were previously being exposed for all the anon mTHP orders, meaning order-1 was not present, and for arm64 64K base pages, orders 12 and 13 were exposed but were not supported internally. Tidy this all up by defining ctrl and stats attribute groups for anon and file separately. Anon ctrl and stats groups are populated for all orders in THP_ORDERS_ALL_ANON and file ctrl and stats groups are populated for all orders in THP_ORDERS_ALL_FILE_DEFAULT. Additionally, create "any" ctrl and stats attribute groups which are populated for all orders in (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DEFAULT). swpout stats use this since they apply to anon and shmem. The side-effect of all this is that different hugepage-*kB directories contain different sets of controls and stats, depending on which memory types support that size. This approach is preferred over the alternative, which is to populate dummy controls and stats for memory types that do not support a given size. [ryan.roberts@arm.com: file pages and shmem can also be split] Link: https://lkml.kernel.org/r/f7ced14c-8bc5-405f-bee7-94f63980f525@arm.comLink: https://lkml.kernel.org/r/20240808111849.651867-3-ryan.roberts@arm.comSigned-off-by:
Ryan Roberts <ryan.roberts@arm.com> Tested-by:
Barry Song <baohua@kernel.org> Reviewed-by:
Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
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Ryan Roberts authored
Patch series "Shmem mTHP controls and stats improvements", v3. This is a small series to tidy up the way the shmem controls and stats are exposed. These patches were previously part of the series at [2], but I decided to split them out since they can go in independently. This patch (of 2): Let's move count_mthp_stat() so that it's always defined, even when THP is disabled. Previously uses of the function in files such as shmem.c, which are compiled even when THP is disabled, required ugly THP ifdeferry. With this cleanup, we can remove those ifdefs and the function resolves to a nop when THP is disabled. I shortly plan to call count_mthp_stat() from more THP-invariant source files. Link: https://lkml.kernel.org/r/20240808111849.651867-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20240808111849.651867-2-ryan.roberts@arm.comSigned-off-by:
Lance Yang <ioworker0@gmail.com> Acked-by:
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- 04 Sep, 2024 31 commits
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Kefeng Wang authored
Use the isolate_folio_to_list() to unify hugetlb/LRU/non-LRU folio isolation, which cleanup code a bit and save a few calls to compound_head(). [wangkefeng.wang@huawei.com: various fixes] Link: https://lkml.kernel.org/r/20240829150500.2599549-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240827114728.3212578-6-wangkefeng.wang@huawei.comSigned-off-by:
Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Cc: David Hildenbrand <david@redhat.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by:
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Kefeng Wang authored
Add isolate_folio_to_list() helper to try to isolate HugeTLB, no-LRU movable and LRU folios to a list, which will be reused by do_migrate_range() from memory hotplug soon, also drop the mf_isolate_folio() since we could directly use new helper in the soft_offline_in_use_page(). Link: https://lkml.kernel.org/r/20240827114728.3212578-5-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Commit b15c8726 ("hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined") don't handle the hugetlb pages, the endless loop still occur if offline a hwpoison hugetlb page, luckly, after the commit e591ef7d ("mm, hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage"), the HPageMigratable of hugetlb page will be cleared, and the hwpoison hugetlb page will be skipped in scan_movable_pages(), so the endless loop issue is fixed. However if the HPageMigratable() check passed(without reference and lock), the hugetlb page may be hwpoisoned, it won't cause issue since the hwpoisoned page will be handled correctly in the next movable pages scan loop, and it will be isolated in do_migrate_range() but fails to migrate. In order to avoid the unnecessary isolation and unify all hwpoisoned page handling, let's unconditionally check hwpoison firstly, and if it is a hwpoisoned hugetlb page, try to unmap it as the catch all safety net like normal page does. Link: https://lkml.kernel.org/r/20240827114728.3212578-4-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Add unmap_poisoned_folio() helper which will be reused by do_migrate_range() from memory hotplug soon. [akpm@linux-foundation.org: whitespace tweak, per Miaohe Lin] Link: https://lkml.kernel.org/r/1f80c7e3-c30d-1ac1-6a36-d1a5f5907f7c@huawei.com Link: https://lkml.kernel.org/r/20240827114728.3212578-3-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Patch series "mm: memory_hotplug: improve do_migrate_range()", v3. Unify hwpoisoned page handling and isolation of HugeTLB/LRU/non-LRU movable page, also convert to use folios in do_migrate_range(). This patch (of 5): Directly use a folio for HugeTLB and THP when calculate the next pfn, then remove unused head variable. Link: https://lkml.kernel.org/r/20240827114728.3212578-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240827114728.3212578-2-wangkefeng.wang@huawei.comSigned-off-by:
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SeongJae Park authored
'--kunitconfig' option of 'kunit.py run' supports '.kunitconfig' file name convention. Add the file for DAMON kunit tests for more convenient kunit run. Link: https://lkml.kernel.org/r/20240827030336.7930-10-sj@kernel.orgSigned-off-by:
SeongJae Park <sj@kernel.org> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: David Gow <davidgow@google.com> Signed-off-by:
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SeongJae Park authored
There was a discussion about better places for kunit test code[1] and test file name suffix[2]. Folowwing the conclusion, move kunit tests for DAMON to mm/damon/tests/ subdirectory and rename those. [1] https://lore.kernel.org/CABVgOS=pUdWb6NDHszuwb1HYws4a1-b1UmN=i8U_ED7HbDT0mg@mail.gmail.com [2] https://lore.kernel.org/CABVgOSmKwPq7JEpHfS6sbOwsR0B-DBDk_JP-ZD9s9ZizvpUjbQ@mail.gmail.com Link: https://lkml.kernel.org/r/20240827030336.7930-9-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
The test depends on registration of DAMON_OPS_PADDR. It would be registered only when CONFIG_DAMON_PADDR is set. DAMON core kunit tests do fake ops registration for such case. However, the functions for such fake ops registration is not available to DAMON debugfs interface. Just skip the test in the case. Link: https://lkml.kernel.org/r/20240827030336.7930-8-sj@kernel.org Fixes: 999b9467 ("mm/damon/dbgfs-test: fix is_target_id() change") Signed-off-by:
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SeongJae Park authored
The test depends on registration of DAMON_OPS_PADDR. It would be registered only when CONFIG_DAMON_PADDR is set. DAMON core kunit tests do fake ops registration for such case. However, the functions for such fake ops registration is not available to DAMON debugfs interface. Just skip the test in the case. Link: https://lkml.kernel.org/r/20240827030336.7930-7-sj@kernel.org Fixes: 999b9467 ("mm/damon/dbgfs-test: fix is_target_id() change") Signed-off-by:
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SeongJae Park authored
DAMON core kunit test can be executed without CONFIG_DAMON_VADDR. In the case, vaddr DAMON ops is not registered. Meanwhile, ops registration kunit test assumes the vaddr ops is registered. Check and handle the case by registrering fake vaddr ops inside the test code. Link: https://lkml.kernel.org/r/20240827030336.7930-6-sj@kernel.org Fixes: 4f540f5a ("mm/damon/core-test: add a kunit test case for ops registration") Signed-off-by:
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SeongJae Park authored
DAMON ops registration kunit test tests both vaddr and paddr use cases in parts of the whole test cases. Basically testing only one ops use case is enough. Do the test with only vaddr use case. Link: https://lkml.kernel.org/r/20240827030336.7930-5-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Some test scripts are missing executable permissions. It causes warnings that make the test output unnecessarily verbose. Add executable permissions. Link: https://lkml.kernel.org/r/20240827030336.7930-4-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Python-based tests creates __pycache__/ directory. Remove it with 'make clean' by defining it as EXTRA_CLEAN. Link: https://lkml.kernel.org/r/20240827030336.7930-3-sj@kernel.org Fixes: b5906f5f ("selftests/damon: add a test for update_schemes_tried_regions sysfs command") Signed-off-by:
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SeongJae Park authored
Patch series "misc fixups for DAMON {self,kunit} tests". This patchset is for minor fixups of DAMON selftests and kunit tests. First three patches make DAMON selftests more cleanly maintained (patches 1 and 2) without unnecessary warnings (patch 3). Following six patches remove unnecessary test case (patch 4), handle configs combinations that can make tests fail (patches 5-7), reorganize the test files following the new guideline (patch 8), and add reference kunitconfig for DAMON kunit tests (patch 9). This patch (of 9): DAMON selftests build access_memory_even, but its not on the .gitignore list. Add it to make 'git status' output cleaner. Link: https://lkml.kernel.org/r/20240827030336.7930-1-sj@kernel.org Link: https://lkml.kernel.org/r/20240827030336.7930-2-sj@kernel.org Fixes: c94df805 ("selftests/damon: implement a program for even-numbered memory regions access") Signed-off-by: -
Yujie Liu authored
Problem statement: Since commit fc137c0d ("sched/numa: enhance vma scanning logic"), the Numa vma scan overhead has been reduced a lot. Meanwhile, the reducing of the vma scan might create less Numa page fault information. The insufficient information makes it harder for the Numa balancer to make decision. Later, commit b7a5b537 ("sched/numa: Complete scanning of partial VMAs regardless of PID activity") and commit 84db47ca ("sched/numa: Fix mm numa_scan_seq based unconditional scan") are found to bring back part of the performance. Recently when running SPECcpu omnetpp_r on a 320 CPUs/2 Sockets system, a long duration of remote Numa node read was observed by PMU events: A few cores having ~500MB/s remote memory access for ~20 seconds. It causes high core-to-core variance and performance penalty. After the investigation, it is found that many vmas are skipped due to the active PID check. According to the trace events, in most cases, vma_is_accessed() returns false because the history access info stored in pids_active array has been cleared. Proposal: The main idea is to adjust vma_is_accessed() to let it return true easier. Thus compare the diff between mm->numa_scan_seq and vma->numab_state->prev_scan_seq. If the diff has exceeded the threshold, scan the vma. This patch especially helps the cases where there are small number of threads, like the process-based SPECcpu. Without this patch, if the SPECcpu process access the vma at the beginning, then sleeps for a long time, the pid_active array will be cleared. A a result, if this process is woken up again, it never has a chance to set prot_none anymore. Because only the first 2 times of access is granted for vma scan: (current->mm->numa_scan_seq) - vma->numab_state->start_scan_seq) < 2 to be worse, no other threads within the task can help set the prot_none. This causes information lost. Raghavendra helped test current patch and got the positive result on the AMD platform: autonumabench NUMA01 base patched Amean syst-NUMA01 194.05 ( 0.00%) 165.11 * 14.92%* Amean elsp-NUMA01 324.86 ( 0.00%) 315.58 * 2.86%* Duration User 380345.36 368252.04 Duration System 1358.89 1156.23 Duration Elapsed 2277.45 2213.25 autonumabench NUMA02 Amean syst-NUMA02 1.12 ( 0.00%) 1.09 * 2.93%* Amean elsp-NUMA02 3.50 ( 0.00%) 3.56 * -1.84%* Duration User 1513.23 1575.48 Duration System 8.33 8.13 Duration Elapsed 28.59 29.71 kernbench Amean user-256 22935.42 ( 0.00%) 22535.19 * 1.75%* Amean syst-256 7284.16 ( 0.00%) 7608.72 * -4.46%* Amean elsp-256 159.01 ( 0.00%) 158.17 * 0.53%* Duration User 68816.41 67615.74 Duration System 21873.94 22848.08 Duration Elapsed 506.66 504.55 Intel 256 CPUs/2 Sockets: autonuma benchmark also shows improvements: v6.10-rc5 v6.10-rc5 +patch Amean syst-NUMA01 245.85 ( 0.00%) 230.84 * 6.11%* Amean syst-NUMA01_THREADLOCAL 205.27 ( 0.00%) 191.86 * 6.53%* Amean syst-NUMA02 18.57 ( 0.00%) 18.09 * 2.58%* Amean syst-NUMA02_SMT 2.63 ( 0.00%) 2.54 * 3.47%* Amean elsp-NUMA01 517.17 ( 0.00%) 526.34 * -1.77%* Amean elsp-NUMA01_THREADLOCAL 99.92 ( 0.00%) 100.59 * -0.67%* Amean elsp-NUMA02 15.81 ( 0.00%) 15.72 * 0.59%* Amean elsp-NUMA02_SMT 13.23 ( 0.00%) 12.89 * 2.53%* v6.10-rc5 v6.10-rc5 +patch Duration User 1064010.16 1075416.23 Duration System 3307.64 3104.66 Duration Elapsed 4537.54 4604.73 The SPECcpu remote node access issue disappears with the patch applied. Link: https://lkml.kernel.org/r/20240827112958.181388-1-yu.c.chen@intel.com Fixes: fc137c0d ("sched/numa: enhance vma scanning logic") Signed-off-by:
Chen Yu <yu.c.chen@intel.com> Co-developed-by:
Yujie Liu <yujie.liu@intel.com> Reported-by:
Xiaoping Zhou <xiaoping.zhou@intel.com> Reviewed-and-tested-by:
Raghavendra K T <raghavendra.kt@amd.com> Acked-by:
Mel Gorman <mgorman@techsingularity.net> Cc: "Chen, Tim C" <tim.c.chen@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Raghavendra K T <raghavendra.kt@amd.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by:
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Yanfei Xu authored
commit 823430c8 ("memory tier: consolidate the initialization of memory tiers") introduces a locking change that use guard(mutex) to instead of mutex_lock/unlock() for memory_tier_lock. It unexpectedly expanded the locked region to include the hotplug_memory_notifier(), as a result, it triggers an locking dependency detected of ABBA deadlock. Exclude hotplug_memory_notifier() from the locked region to fixing it. The deadlock scenario is that when a memory online event occurs, the execution of memory notifier will access the read lock of the memory_chain.rwsem, then the reigistration of the memory notifier in memory_tier_init() acquires the write lock of the memory_chain.rwsem while holding memory_tier_lock. Then the memory online event continues to invoke the memory hotplug callback registered by memory_tier_init(). Since this callback tries to acquire the memory_tier_lock, a deadlock occurs. In fact, this deadlock can't happen because memory_tier_init() always executes before memory online events happen due to the subsys_initcall() has an higher priority than module_init(). [ 133.491106] WARNING: possible circular locking dependency detected [ 133.493656] 6.11.0-rc2+ #146 Tainted: G O N [ 133.504290] ------------------------------------------------------ [ 133.515194] (udev-worker)/1133 is trying to acquire lock: [ 133.525715] ffffffff87044e28 (memory_tier_lock){+.+.}-{3:3}, at: memtier_hotplug_callback+0x383/0x4b0 [ 133.536449] [ 133.536449] but task is already holding lock: [ 133.549847] ffffffff875d3310 ((memory_chain).rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x60/0xb0 [ 133.556781] [ 133.556781] which lock already depends on the new lock. [ 133.556781] [ 133.569957] [ 133.569957] the existing dependency chain (in reverse order) is: [ 133.577618] [ 133.577618] -> #1 ((memory_chain).rwsem){++++}-{3:3}: [ 133.584997] down_write+0x97/0x210 [ 133.588647] blocking_notifier_chain_register+0x71/0xd0 [ 133.592537] register_memory_notifier+0x26/0x30 [ 133.596314] memory_tier_init+0x187/0x300 [ 133.599864] do_one_initcall+0x117/0x5d0 [ 133.603399] kernel_init_freeable+0xab0/0xeb0 [ 133.606986] kernel_init+0x28/0x2f0 [ 133.610312] ret_from_fork+0x59/0x90 [ 133.613652] ret_from_fork_asm+0x1a/0x30 [ 133.617012] [ 133.617012] -> #0 (memory_tier_lock){+.+.}-{3:3}: [ 133.623390] __lock_acquire+0x2efd/0x5c60 [ 133.626730] lock_acquire+0x1ce/0x580 [ 133.629757] __mutex_lock+0x15c/0x1490 [ 133.632731] mutex_lock_nested+0x1f/0x30 [ 133.635717] memtier_hotplug_callback+0x383/0x4b0 [ 133.638748] notifier_call_chain+0xbf/0x370 [ 133.641647] blocking_notifier_call_chain+0x76/0xb0 [ 133.644636] memory_notify+0x2e/0x40 [ 133.647427] online_pages+0x597/0x720 [ 133.650246] memory_subsys_online+0x4f6/0x7f0 [ 133.653107] device_online+0x141/0x1d0 [ 133.655831] online_memory_block+0x4d/0x60 [ 133.658616] walk_memory_blocks+0xc0/0x120 [ 133.661419] add_memory_resource+0x51d/0x6c0 [ 133.664202] add_memory_driver_managed+0xf5/0x180 [ 133.667060] dev_dax_kmem_probe+0x7f7/0xb40 [kmem] [ 133.669949] dax_bus_probe+0x147/0x230 [ 133.672687] really_probe+0x27f/0xac0 [ 133.675463] __driver_probe_device+0x1f3/0x460 [ 133.678493] driver_probe_device+0x56/0x1b0 [ 133.681366] __driver_attach+0x277/0x570 [ 133.684149] bus_for_each_dev+0x145/0x1e0 [ 133.686937] driver_attach+0x49/0x60 [ 133.689673] bus_add_driver+0x2f3/0x6b0 [ 133.692421] driver_register+0x170/0x4b0 [ 133.695118] __dax_driver_register+0x141/0x1b0 [ 133.697910] dax_kmem_init+0x54/0xff0 [kmem] [ 133.700794] do_one_initcall+0x117/0x5d0 [ 133.703455] do_init_module+0x277/0x750 [ 133.706054] load_module+0x5d1d/0x74f0 [ 133.708602] init_module_from_file+0x12c/0x1a0 [ 133.711234] idempotent_init_module+0x3f1/0x690 [ 133.713937] __x64_sys_finit_module+0x10e/0x1a0 [ 133.716492] x64_sys_call+0x184d/0x20d0 [ 133.719053] do_syscall_64+0x6d/0x140 [ 133.721537] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 133.724239] [ 133.724239] other info that might help us debug this: [ 133.724239] [ 133.730832] Possible unsafe locking scenario: [ 133.730832] [ 133.735298] CPU0 CPU1 [ 133.737759] ---- ---- [ 133.740165] rlock((memory_chain).rwsem); [ 133.742623] lock(memory_tier_lock); [ 133.745357] lock((memory_chain).rwsem); [ 133.748141] lock(memory_tier_lock); [ 133.750489] [ 133.750489] *** DEADLOCK *** [ 133.750489] [ 133.756742] 6 locks held by (udev-worker)/1133: [ 133.759179] #0: ffff888207be6158 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x26c/0x570 [ 133.762299] #1: ffffffff875b5868 (device_hotplug_lock){+.+.}-{3:3}, at: lock_device_hotplug+0x20/0x30 [ 133.765565] #2: ffff88820cf6a108 (&dev->mutex){....}-{3:3}, at: device_online+0x2f/0x1d0 [ 133.768978] #3: ffffffff86d08ff0 (cpu_hotplug_lock){++++}-{0:0}, at: mem_hotplug_begin+0x17/0x30 [ 133.772312] #4: ffffffff8702dfb0 (mem_hotplug_lock){++++}-{0:0}, at: mem_hotplug_begin+0x23/0x30 [ 133.775544] #5: ffffffff875d3310 ((memory_chain).rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x60/0xb0 [ 133.779113] [ 133.779113] stack backtrace: [ 133.783728] CPU: 5 UID: 0 PID: 1133 Comm: (udev-worker) Tainted: G O N 6.11.0-rc2+ #146 [ 133.787220] Tainted: [O]=OOT_MODULE, [N]=TEST [ 133.789948] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 [ 133.793291] Call Trace: [ 133.795826] <TASK> [ 133.798284] dump_stack_lvl+0xea/0x150 [ 133.801025] dump_stack+0x19/0x20 [ 133.803609] print_circular_bug+0x477/0x740 [ 133.806341] check_noncircular+0x2f4/0x3e0 [ 133.809056] ? __pfx_check_noncircular+0x10/0x10 [ 133.811866] ? __pfx_lockdep_lock+0x10/0x10 [ 133.814670] ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30 [ 133.817610] __lock_acquire+0x2efd/0x5c60 [ 133.820339] ? __pfx___lock_acquire+0x10/0x10 [ 133.823128] ? __dax_driver_register+0x141/0x1b0 [ 133.825926] ? do_one_initcall+0x117/0x5d0 [ 133.828648] lock_acquire+0x1ce/0x580 [ 133.831349] ? memtier_hotplug_callback+0x383/0x4b0 [ 133.834293] ? __pfx_lock_acquire+0x10/0x10 [ 133.837134] __mutex_lock+0x15c/0x1490 [ 133.839829] ? memtier_hotplug_callback+0x383/0x4b0 [ 133.842753] ? memtier_hotplug_callback+0x383/0x4b0 [ 133.845602] ? __this_cpu_preempt_check+0x21/0x30 [ 133.848438] ? __pfx___mutex_lock+0x10/0x10 [ 133.851200] ? __pfx_lock_acquire+0x10/0x10 [ 133.853935] ? global_dirty_limits+0xc0/0x160 [ 133.856699] ? __sanitizer_cov_trace_switch+0x58/0xa0 [ 133.859564] mutex_lock_nested+0x1f/0x30 [ 133.862251] ? mutex_lock_nested+0x1f/0x30 [ 133.864964] memtier_hotplug_callback+0x383/0x4b0 [ 133.867752] notifier_call_chain+0xbf/0x370 [ 133.870550] ? writeback_set_ratelimit+0xe8/0x160 [ 133.873372] blocking_notifier_call_chain+0x76/0xb0 [ 133.876311] memory_notify+0x2e/0x40 [ 133.879013] online_pages+0x597/0x720 [ 133.881686] ? irqentry_exit+0x3e/0xa0 [ 133.884397] ? __pfx_online_pages+0x10/0x10 [ 133.887244] ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30 [ 133.890299] ? mhp_init_memmap_on_memory+0x7a/0x1c0 [ 133.893203] memory_subsys_online+0x4f6/0x7f0 [ 133.896099] ? __pfx_memory_subsys_online+0x10/0x10 [ 133.899039] ? xa_load+0x16d/0x2e0 [ 133.901667] ? __pfx_xa_load+0x10/0x10 [ 133.904366] ? __pfx_memory_subsys_online+0x10/0x10 [ 133.907218] device_online+0x141/0x1d0 [ 133.909845] online_memory_block+0x4d/0x60 [ 133.912494] walk_memory_blocks+0xc0/0x120 [ 133.915104] ? __pfx_online_memory_block+0x10/0x10 [ 133.917776] add_memory_resource+0x51d/0x6c0 [ 133.920404] ? __pfx_add_memory_resource+0x10/0x10 [ 133.923104] ? _raw_write_unlock+0x31/0x60 [ 133.925781] ? register_memory_resource+0x119/0x180 [ 133.928450] add_memory_driver_managed+0xf5/0x180 [ 133.931036] dev_dax_kmem_probe+0x7f7/0xb40 [kmem] [ 133.933665] ? __pfx_dev_dax_kmem_probe+0x10/0x10 [kmem] [ 133.936332] ? __pfx___up_read+0x10/0x10 [ 133.938878] dax_bus_probe+0x147/0x230 [ 133.941332] ? __pfx_dax_bus_probe+0x10/0x10 [ 133.943954] really_probe+0x27f/0xac0 [ 133.946387] ? __sanitizer_cov_trace_const_cmp1+0x1e/0x30 [ 133.949106] __driver_probe_device+0x1f3/0x460 [ 133.951704] ? parse_option_str+0x149/0x190 [ 133.954241] driver_probe_device+0x56/0x1b0 [ 133.956749] __driver_attach+0x277/0x570 [ 133.959228] ? __pfx___driver_attach+0x10/0x10 [ 133.961776] bus_for_each_dev+0x145/0x1e0 [ 133.964367] ? __pfx_bus_for_each_dev+0x10/0x10 [ 133.967019] ? __kasan_check_read+0x15/0x20 [ 133.969543] ? _raw_spin_unlock+0x31/0x60 [ 133.972132] driver_attach+0x49/0x60 [ 133.974536] bus_add_driver+0x2f3/0x6b0 [ 133.977044] driver_register+0x170/0x4b0 [ 133.979480] __dax_driver_register+0x141/0x1b0 [ 133.982126] ? __pfx_dax_kmem_init+0x10/0x10 [kmem] [ 133.984724] dax_kmem_init+0x54/0xff0 [kmem] [ 133.987284] ? __pfx_dax_kmem_init+0x10/0x10 [kmem] [ 133.989965] do_one_initcall+0x117/0x5d0 [ 133.992506] ? __pfx_do_one_initcall+0x10/0x10 [ 133.995185] ? __kasan_kmalloc+0x88/0xa0 [ 133.997748] ? kasan_poison+0x3e/0x60 [ 134.000288] ? kasan_unpoison+0x2c/0x60 [ 134.002762] ? kasan_poison+0x3e/0x60 [ 134.005202] ? __asan_register_globals+0x62/0x80 [ 134.007753] ? __pfx_dax_kmem_init+0x10/0x10 [kmem] [ 134.010439] do_init_module+0x277/0x750 [ 134.012953] load_module+0x5d1d/0x74f0 [ 134.015406] ? __pfx_load_module+0x10/0x10 [ 134.017887] ? __pfx_ima_post_read_file+0x10/0x10 [ 134.020470] ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30 [ 134.023127] ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20 [ 134.025767] ? security_kernel_post_read_file+0xa2/0xd0 [ 134.028429] ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20 [ 134.031162] ? kernel_read_file+0x503/0x820 [ 134.033645] ? __pfx_kernel_read_file+0x10/0x10 [ 134.036232] ? __pfx___lock_acquire+0x10/0x10 [ 134.038766] init_module_from_file+0x12c/0x1a0 [ 134.041291] ? init_module_from_file+0x12c/0x1a0 [ 134.043936] ? __pfx_init_module_from_file+0x10/0x10 [ 134.046516] ? __this_cpu_preempt_check+0x21/0x30 [ 134.049091] ? __kasan_check_read+0x15/0x20 [ 134.051551] ? do_raw_spin_unlock+0x60/0x210 [ 134.054077] idempotent_init_module+0x3f1/0x690 [ 134.056643] ? __pfx_idempotent_init_module+0x10/0x10 [ 134.059318] ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20 [ 134.061995] ? __fget_light+0x17d/0x210 [ 134.064428] __x64_sys_finit_module+0x10e/0x1a0 [ 134.066976] x64_sys_call+0x184d/0x20d0 [ 134.069405] do_syscall_64+0x6d/0x140 [ 134.071926] entry_SYSCALL_64_after_hwframe+0x76/0x7e [yanfei.xu@intel.com: add mutex_lock/unlock() pair back] Link: https://lkml.kernel.org/r/20240830102447.1445296-1-yanfei.xu@intel.com Link: https://lkml.kernel.org/r/20240827113614.1343049-1-yanfei.xu@intel.com Fixes: 823430c8 ("memory tier: consolidate the initialization of memory tiers") Signed-off-by:
Yanfei Xu <yanfei.xu@intel.com> Reviewed-by:
"Huang, Ying" <ying.huang@intel.com> Cc: Ho-Ren (Jack) Chuang <horen.chuang@linux.dev> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by:
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Uladzislau Rezki (Sony) authored
The aim is to simplify and making the vm_area_alloc_pages() function less confusing as it became more clogged nowadays: - eliminate a "bulk_gfp" variable and do not overwrite a gfp flag for bulk allocator; - drop __GFP_NOFAIL flag for high-order-page requests on upper layer. It becomes less spread between levels when it comes to __GFP_NOFAIL allocations; - add a comment about a fallback path if high-order attempt is unsuccessful because for such cases __GFP_NOFAIL is dropped; - fix a typo in a commit message. Link: https://lkml.kernel.org/r/20240827190916.34242-1-urezki@gmail.comSigned-off-by:
Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by:
Michal Hocko <mhocko@suse.com> Reviewed-by:
Baoquan He <bhe@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com> Signed-off-by:
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Lorenzo Stoakes authored
In commit 714965ca ("mm/mmap: start distinguishing if vma can be removed in mergeability test") we relaxed the VMA merge rules for VMAs possessing a vm_ops->close() hook, permitting this operation in instances where we wouldn't delete the VMA as part of the merge operation. This was later corrected in commit fc0c8f90 ("mm, mmap: fix vma_merge() case 7 with vma_ops->close") to account for a subtle case that the previous commit had not taken into account. In both instances, we first rely on is_mergeable_vma() to determine whether we might be dealing with a VMA that might be removed, taking advantage of the fact that a 'previous' VMA will never be deleted, only VMAs that follow it. The second patch corrects the instance where a merge of the previous VMA into a subsequent one did not correctly check whether the subsequent VMA had a vm_ops->close() handler. Both changes prevent merge cases that are actually permissible (for instance a merge of a VMA into a following VMA with a vm_ops->close(), but with no previous VMA, which would result in the next VMA being extended, not deleted). In addition, both changes fail to consider the case where a VMA that would otherwise be merged with the previous and next VMA might have vm_ops->close(), on the assumption that for this to be the case, all three would have to have the same vma->vm_file to be mergeable and thus the same vm_ops. And in addition both changes operate at 50,000 feet, trying to guess whether a VMA will be deleted. As we have majorly refactored the VMA merge operation and de-duplicated code to the point where we know precisely where deletions will occur, this patch removes the aforementioned checks altogether and instead explicitly checks whether a VMA will be deleted. In cases where a reduced merge is still possible (where we merge both previous and next VMA but the next VMA has a vm_ops->close hook, meaning we could just merge the previous and current VMA), we do so, otherwise the merge is not permitted. We take advantage of our userland testing to assert that this functions correctly - replacing the previous limited vm_ops->close() tests with tests for every single case where we delete a VMA. We also update all testing for both new and modified VMAs to set vma->vm_ops->close() in every single instance where this would not prevent the merge, to assert that we never do so. Link: https://lkml.kernel.org/r/9f96b8cfeef3d14afabddac3d6144afdfbef2e22.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Mark Brown <broonie@kernel.org> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by:
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Lorenzo Stoakes authored
The existing vma_merge() function is no longer required to handle what were previously referred to as cases 1-3 (i.e. the merging of a new VMA), as this is now handled by vma_merge_new_vma(). Additionally, simplify the convoluted control flow of the original, maintaining identical logic only expressed more clearly and doing away with a complicated set of cases, rather logically examining each possible outcome - merging of both the previous and subsequent VMA, merging of the previous VMA and merging of the subsequent VMA alone. We now utilise the previously implemented commit_merge() function to share logic with vma_expand() de-duplicating code and providing less surface area for bugs and confusion. In order to do so, we adjust this function to accept parameters specific to merging existing ranges. Link: https://lkml.kernel.org/r/2cf6016b7bfcc4965fc3cde10827560c42e4f12c.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
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Lorenzo Stoakes authored
Pull the part of vma_expand() which actually commits the merge operation, that is inserts it into the maple tree and sets the VMA's vma->vm_start and vma->vm_end parameters, into its own function. We implement only the parts needed for vma_expand() which now as a result of previous work is also the means by which new VMA ranges are merged. The next commit in the series will implement merging of existing ranges which will extend commit_merge() to accommodate this case and result in all merges using this common code. Link: https://lkml.kernel.org/r/7b985a20dfa549e3c370cd274d732b64c44f6dbd.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
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Lorenzo Stoakes authored
Now we have abstracted merge behaviour for new VMA ranges, we are able to render vma_prepare(), init_vma_prep(), vma_complete(), can_vma_merge_before() and can_vma_merge_after() static and internal to vma.c. These are internal implementation details of kernel VMA manipulation and merging mechanisms and thus should not be exposed. This also renders the functions userland testable. Link: https://lkml.kernel.org/r/7f7f1c34ce10405a6aab2714c505af3cf41b7851.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
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Lorenzo Stoakes authored
Abstract vma_merge_new_vma() to use vma_merge_struct and rename the resultant function vma_merge_new_range() to be clear what the purpose of this function is - a new VMA is desired in the specified range, and we wish to see if it is possible to 'merge' surrounding VMAs into this range rather than having to allocate a new VMA. Note that this function uses vma_extend() exclusively, so adopts its requirement that the iterator point at or before the gap. We add an assert to this effect. This is as opposed to vma_merge_existing_range(), which will be introduced in a subsequent commit, and provide the same functionality for cases in which we are modifying an existing VMA. In mmap_region() and do_brk_flags() we open code scenarios where we prefer to use vma_expand() rather than invoke a full vma_merge() operation. Abstract this logic and eliminate all of the open-coding, and also use the same logic for all cases where we add new VMAs to, rather than ultimately use vma_merge(), rather use vma_expand(). Doing so removes duplication and simplifies VMA merging in all such cases, laying the ground for us to eliminate the merging of new VMAs in vma_merge() altogether. Also add the ability for the vmg to track state, and able to report errors, allowing for us to differentiate a failed merge from an inability to allocate memory in callers. This makes it far easier to understand what is happening in these cases avoiding confusion, bugs and allowing for future optimisation. Also introduce vma_iter_next_rewind() to allow for retrieval of the next, and (optionally) the prev VMA, rewinding to the start of the previous gap. Introduce are_anon_vmas_compatible() to abstract individual VMA anon_vma comparison for the case of merging on both sides where the anon_vma of the VMA being merged maybe compatible with prev and next, but prev and next's anon_vma's may not be compatible with each other. Finally also introduce can_vma_merge_left() / can_vma_merge_right() to check adjacent VMA compatibility and that they are indeed adjacent. Link: https://lkml.kernel.org/r/49d37c0769b6b9dc03b27fe4d059173832556392.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
Mark Brown <broonie@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by:
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Lorenzo Stoakes authored
The purpose of the vmg is to thread merge state through functions and avoid egregious parameter lists. We expand this to vma_expand(), which is used for a number of merge cases. Accordingly, adjust its callers, mmap_region() and relocate_vma_down(), to use a vmg. An added purpose of this change is the ability in a future commit to perform all new VMA range merging using vma_expand(). Link: https://lkml.kernel.org/r/4bc8c9dbc9ca52452ef8e587b28fe555854ceb38.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Mark Brown <broonie@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Bert Karwatzki <spasswolf@web.de> Cc: Jeff Xu <jeffxu@chromium.org> Cc: Jiri Olsa <olsajiri@gmail.com> Cc: Kees Cook <kees@kernel.org> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Paul E. McKenney" <paulmck@kernel.org> Cc: Paul Moore <paul@paul-moore.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by:
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Lorenzo Stoakes authored
Both can_vma_merge_before() and can_vma_merge_after() are invoked after checking for compatible VMA NUMA policy, we can simply move this to is_mergeable_vma() and abstract this altogether. In mmap_region() we set vmg->policy to NULL, so the policy comparisons checked in can_vma_merge_before() and can_vma_merge_after() are exactly equivalent to !vma_policy(vmg.next) and !vma_policy(vmg.prev). Equally, in do_brk_flags(), vmg->policy is NULL, so the can_vma_merge_after() is checking !vma_policy(vma), as we set vmg.prev to vma. In vma_merge(), we compare prev and next policies with vmg->policy before checking can_vma_merge_after() and can_vma_merge_before() respectively, which this patch causes to be checked in precisely the same way. This therefore maintains precisely the same logic as before, only now abstracted into is_mergeable_vma(). Link: https://lkml.kernel.org/r/0dbff286d9c4988333bc6f4ff3734cb95dd5410a.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
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Lorenzo Stoakes authored
Rather than passing around huge numbers of parameters to numerous helper functions, abstract them into a single struct that we thread through the operation, the vma_merge_struct ('vmg'). Adjust vma_merge() and vma_modify() to accept this parameter, as well as predicate functions can_vma_merge_before(), can_vma_merge_after(), and the vma_modify_...() helper functions. Also introduce VMG_STATE() and VMG_VMA_STATE() helper macros to allow for easy vmg declaration. We additionally remove the requirement that vma_merge() is passed a VMA object representing the candidate new VMA. Previously it used this to obtain the mm_struct, file and anon_vma properties of the proposed range (a rather confusing state of affairs), which are now provided by the vmg directly. We also remove the pgoff calculation previously performed vma_modify(), and instead calculate this in VMG_VMA_STATE() via the vma_pgoff_offset() helper. Link: https://lkml.kernel.org/r/a955aad09d81329f6fbeb636b2dd10cde7b73dab.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by: -
Lorenzo Stoakes authored
Add a variety of VMA merge unit tests to assert that the behaviour of VMA merge is correct at an abstract level and VMAs are merged or not merged as expected. These are intentionally added _before_ we start refactoring vma_merge() in order that we can continually assert correctness throughout the rest of the series. In order to reduce churn going forward, we backport the vma_merge_struct data type to the test code which we introduce and use in a future commit, and add wrappers around the merge new and existing VMA cases. Link: https://lkml.kernel.org/r/1c7a0b43cfad2c511a6b1b52f3507696478ff51a.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
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Lorenzo Stoakes authored
Patch series "mm: remove vma_merge()", v3. The infamous vma_merge() function has been the cause of a great deal of pain, bugs and confusion for a very long time. It is subtle, contains many corner cases, tries to do far too much and is as a result very fragile. The fact that the function requires there to be a numbering system to cover each possible eventuality with references to each in the many branches of its implementation as to which case you are looking at speaks to all this. Some of this complexity is inherent - unfortunately there is no getting away from the need to figure out precisely how to execute the merge, whether we need to remove VMAs, whether it is safe to do so, what constitutes a mergeable VMA and so on. However, a lot of the complexity is not inherent but instead a product of the function's 'organic' development. Liam has gone to great lengths to improve the situation as a part of his maple tree implementation, greatly improving the readability of the code, and Vlastimil and myself have additionally gone to lengths to try to improve things further. However, with the availability of userland VMA testing, it now becomes possible to perform a rather more significant refactoring while maintaining confidence in its correct operation. An attempt was previously made by Vlastimil [0] to eliminate vma_merge(), however it was rather - brutal - and an astute reader might refer to the date of that patch for insight as to its intent. This series instead divides merge operations into two natural kinds - merges which occur when a NEW vma is being added to the address space, and merges which occur when a vma is being MODIFIED. Happily, the vma_expand() function introduced by Liam, which has the capacity for also deleting a subsequent VMA, covers each of the NEW vma cases. By abstracting the actual final commit of changes to a VMA to its own function, commit_merge() and writing a wrapper around vma_expand() for new VMA cases vma_merge_new_range(), we can avoid having to use vma_merge() for these instances altogether. By doing so we are also able to then de-duplicate all existing merge logic in mmap_region() and do_brk_flags() and have everything invoke this new function, so we universally take the same approach to merging new VMAs. Having done so, we can then completely rework vma_merge() into vma_merge_existing_range() and use this for the instances where a merge is proposed for a region of an existing VMA. This eliminates vma_merge() and its numbered cases and instead divides things into logical cases - merge both, merge left, merge right (the latter 2 being either partial or full merges). The code is heavily annotated with ASCII diagrams and greatly simplified in comparison to the existing vma_merge() function. Having made this change, we take the opportunity to address an issue with merging VMAs possessing a vm_ops->close() hook - commit 714965ca ("mm/mmap: start distinguishing if vma can be removed in mergeability test") and commit fc0c8f90 ("mm, mmap: fix vma_merge() case 7 with vma_ops->close") make efforts to relax how we handle these, making assumptions about which VMAs might end up deleted (and thus, if possessing a vm_ops->close() hook, cannot be). This refactor means we do not need to guess, so instead explicitly only disallow merge in instances where a VMA with a vm_ops->close() hook would be deleted (and try a smaller merge in cases where this is possible). In addition to these changes, we introduce a new vma_merge_struct abstraction to allow VMA merge state to be threaded through the operation neatly. There is heavy unit testing provided for all merge functionality, added prior to the refactoring, allowing for before/after testing. The vm_ops->close() change also introduces exhaustive testing to demonstrate that this functions as expected, and in addition to this the reproduction code from commit fc0c8f90 ("mm, mmap: fix vma_merge() case 7 with vma_ops->close") was tested and confirmed passing. [0]:https://lore.kernel.org/linux-mm/20240401192623.18575-2-vbabka@suse.cz/ This patch (of 10): Have vma.o depend on its source dependencies explicitly, as previously these were simply being ignored as existing object files were up to date. This now correctly re-triggers the build if mm/ source is changed as well as local source code. Also set clean as a phony rule. Link: https://lkml.kernel.org/r/cover.1725040657.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/e3ea58f08364ae5432c9a074de0195a7c7e0b04a.1725040657.git.lorenzo.stoakes@oracle.comSigned-off-by:
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Liam R. Howlett authored
The vma_munmap_struct has a hole of 4 bytes and pushes the struct to three cachelines. Relocating the three booleans upwards allows for the struct to only use two cachelines (as reported by pahole on amd64). Before: struct vma_munmap_struct { struct vma_iterator * vmi; /* 0 8 */ struct vm_area_struct * vma; /* 8 8 */ struct vm_area_struct * prev; /* 16 8 */ struct vm_area_struct * next; /* 24 8 */ struct list_head * uf; /* 32 8 */ long unsigned int start; /* 40 8 */ long unsigned int end; /* 48 8 */ long unsigned int unmap_start; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ long unsigned int unmap_end; /* 64 8 */ int vma_count; /* 72 4 */ /* XXX 4 bytes hole, try to pack */ long unsigned int nr_pages; /* 80 8 */ long unsigned int locked_vm; /* 88 8 */ long unsigned int nr_accounted; /* 96 8 */ long unsigned int exec_vm; /* 104 8 */ long unsigned int stack_vm; /* 112 8 */ long unsigned int data_vm; /* 120 8 */ /* --- cacheline 2 boundary (128 bytes) --- */ bool unlock; /* 128 1 */ bool clear_ptes; /* 129 1 */ bool closed_vm_ops; /* 130 1 */ /* size: 136, cachelines: 3, members: 19 */ /* sum members: 127, holes: 1, sum holes: 4 */ /* padding: 5 */ /* last cacheline: 8 bytes */ }; After: struct vma_munmap_struct { struct vma_iterator * vmi; /* 0 8 */ struct vm_area_struct * vma; /* 8 8 */ struct vm_area_struct * prev; /* 16 8 */ struct vm_area_struct * next; /* 24 8 */ struct list_head * uf; /* 32 8 */ long unsigned int start; /* 40 8 */ long unsigned int end; /* 48 8 */ long unsigned int unmap_start; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ long unsigned int unmap_end; /* 64 8 */ int vma_count; /* 72 4 */ bool unlock; /* 76 1 */ bool clear_ptes; /* 77 1 */ bool closed_vm_ops; /* 78 1 */ /* XXX 1 byte hole, try to pack */ long unsigned int nr_pages; /* 80 8 */ long unsigned int locked_vm; /* 88 8 */ long unsigned int nr_accounted; /* 96 8 */ long unsigned int exec_vm; /* 104 8 */ long unsigned int stack_vm; /* 112 8 */ long unsigned int data_vm; /* 120 8 */ /* size: 128, cachelines: 2, members: 19 */ /* sum members: 127, holes: 1, sum holes: 1 */ }; Link: https://lkml.kernel.org/r/20240830040101.822209-22-Liam.Howlett@oracle.comSigned-off-by: -
Liam R. Howlett authored
The comment has been outdated since 6b73cff2 ("mm: change munmap splitting order and move_vma()"). The move_vma() was altered to fix the fragile state of the accounting since then. Link: https://lkml.kernel.org/r/20240830040101.822209-21-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
The may_expand_vm() check requires the count of the pages within the munmap range. Since this is needed for accounting and obtained later, the reodering of ma_expand_vm() to later in the call stack, after the vma munmap struct (vms) is initialised and the gather stage is potentially run, will allow for a single loop over the vmas. The gather sage does not commit any work and so everything can be undone in the case of a failure. The MAP_FIXED page count is available after the vms_gather_munmap_vmas() call, so use it instead of looping over the vmas twice. Link: https://lkml.kernel.org/r/20240830040101.822209-20-Liam.Howlett@oracle.comSigned-off-by:
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Liam R. Howlett authored
The do_vma_munmap() wrapper existed for callers that didn't have a vma iterator and needed to check the vma mseal status prior to calling the underlying munmap(). All callers now use a vma iterator and since the mseal check has been moved to do_vmi_align_munmap() and the vmas are aligned, this function can just be called instead. do_vmi_align_munmap() can no longer be static as ipc/shm is using it and it is exported via the mm.h header. Link: https://lkml.kernel.org/r/20240830040101.822209-19-Liam.Howlett@oracle.comSigned-off-by:
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