- 04 Oct, 2023 40 commits
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SeongJae Park authored
Patch series "mm/damon: implement DAMOS apply intervals". DAMON-based operation schemes are applied for every aggregation interval. That is mainly because schemes are using nr_accesses, which be complete to be used for every aggregation interval. This makes some DAMOS use cases be tricky. Quota setting under long aggregation interval is one such example. Suppose the aggregation interval is ten seconds, and there is a scheme having CPU quota 100ms per 1s. The scheme will actually uses 100ms per ten seconds, since it cannobe be applied before next aggregation interval. The feature is working as intended, but the results might not that intuitive for some users. This could be fixed by updating the quota to 1s per 10s. But, in the case, the CPU usage of DAMOS could look like spikes, and actually make a bad effect to other CPU-sensitive workloads. Also, with such huge aggregation interval, users may want schemes to be applied more frequently. DAMON provides nr_accesses_bp, which is updated for each sampling interval in a way that reasonable to be used. By using that instead of nr_accesses, DAMOS can have its own time interval and mitigate abovely mentioned issues. This patchset makes DAMOS schemes to use nr_accesses_bp instead of nr_accesses, and have their own timing intervals. Also update DAMOS tried regions sysfs files and DAMOS before_apply tracepoint to use the new data as their source. Note that the interval is zero by default, and it is interpreted to use the aggregation interval instead. This avoids making user-visible behavioral changes. Patches Seuqeunce ----------------- The first patch (patch 1/9) makes DAMOS uses nr_accesses_bp instead of nr_accesses, and following two patches (patches 2/9 and 3/9) updates DAMON sysfs interface for DAMOS tried regions and the DAMOS before_apply tracespoint to use nr_accesses_bp instead of nr_accesses, respectively. The following two patches (patches 4/9 and 5/9) implements the scheme-specific apply interval for DAMON kernel API users and update the design document for the new feature. Finally, the following four patches (patches 6/9, 7/9, 8/9 and 9/9) add support of the feature in DAMON sysfs interface, add a simple selftest test case, and document the new file on the usage and the ABI documents, repsectively. This patch (of 9): DAMON provides nr_accesses_bp, which becomes same to nr_accesses * 10000 for every aggregation interval, but updated every sampling interval with a reasonable accuracy. Since DAMON-based operation schemes are applied in every aggregation interval using nr_accesses, using nr_accesses_bp instead will make no difference to users. Meanwhile, it allows DAMOS to apply the schemes in a time interval that less than the aggregation interval. It could be useful and more flexible for some cases. Do it. Link: https://lkml.kernel.org/r/20230916020945.47296-1-sj@kernel.org Link: https://lkml.kernel.org/r/20230916020945.47296-2-sj@kernel.orgSigned-off-by:
SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <shuah@kernel.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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Matthew Wilcox (Oracle) authored
Convert the callers to expect a folio and remove the unnecesary conversion back to a struct page. Link: https://lkml.kernel.org/r/20230824141325.2704553-4-willy@infradead.orgSigned-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by:
Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by:
Muchun Song <songmuchun@bytedance.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by:
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Matthew Wilcox (Oracle) authored
Anything found on a linked list threaded through ->lru is guaranteed to be a folio as the compound_head found in a tail page overlaps the ->lru member of struct page. So we can pull folios directly off these lists no matter whether pages or folios were added to the list. Link: https://lkml.kernel.org/r/20230824141325.2704553-3-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Patch series "Small hugetlb cleanups", v2. Some trivial folio conversions This patch (of 3): update_and_free_hugetlb_folio puts the memory on hpage_freelist as a folio so we can take it off the list as a folio. Link: https://lkml.kernel.org/r/20230824141325.2704553-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230824141325.2704553-2-willy@infradead.orgSigned-off-by:
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Usama Arif authored
The new boot flow when it comes to initialization of gigantic pages is as follows: - At boot time, for a gigantic page during __alloc_bootmem_hugepage, the region after the first struct page is marked as noinit. - This results in only the first struct page to be initialized in reserve_bootmem_region. As the tail struct pages are not initialized at this point, there can be a significant saving in boot time if HVO succeeds later on. - Later on in the boot, the head page is prepped and the first HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page) - 1 tail struct pages are initialized. - HVO is attempted. If it is not successful, then the rest of the tail struct pages are initialized. If it is successful, no more tail struct pages need to be initialized saving significant boot time. The WARN_ON for increased ref count in gather_bootmem_prealloc was changed to a VM_BUG_ON. This is OK as there should be no speculative references this early in boot process. The VM_BUG_ON's are there just in case such code is introduced. [akpm@linux-foundation.org: make it nicer for 80 cols] Link: https://lkml.kernel.org/r/20230913105401.519709-5-usama.arif@bytedance.comSigned-off-by:
Usama Arif <usama.arif@bytedance.com> Reviewed-by:
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Usama Arif authored
For reserved memory regions marked with this flag, reserve_bootmem_region is not called during memmap_init_reserved_pages. This can be used to avoid struct page initialization for regions which won't need them, for e.g. hugepages with Hugepage Vmemmap Optimization enabled. Link: https://lkml.kernel.org/r/20230913105401.519709-4-usama.arif@bytedance.comSigned-off-by:
Mike Rapoport (IBM) <rppt@kernel.org> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by:
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Usama Arif authored
This allows setting flags to both memblock types and is in preparation for setting flags (for e.g. to not initialize struct pages) on reserved memory region. [usama.arif@bytedance.com: add missing argument definition] Link: https://lkml.kernel.org/r/20230918090657.220463-1-usama.arif@bytedance.com Link: https://lkml.kernel.org/r/20230913105401.519709-3-usama.arif@bytedance.comSigned-off-by:
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Usama Arif authored
Patch series "mm: hugetlb: Skip initialization of gigantic tail struct pages if freed by HVO", v5. This series moves the boot time initialization of tail struct pages of a gigantic page to later on in the boot. Only the HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page) - 1 tail struct pages are initialized at the start. If HVO is successful, then no more tail struct pages need to be initialized. For a 1G hugepage, this series avoid initialization of 262144 - 63 = 262081 struct pages per hugepage. When tested on a 512G system (allocating 500 1G hugepages), the kexec-boot times with DEFERRED_STRUCT_PAGE_INIT enabled are: - with patches, HVO enabled: 1.32 seconds - with patches, HVO disabled: 2.15 seconds - without patches, HVO enabled: 3.90 seconds - without patches, HVO disabled: 3.58 seconds This represents an approximately 70% reduction in boot time and will significantly reduce server downtime when using a large number of gigantic pages. This patch (of 4): If tail page prep and initialization is skipped, then the "start" page will not contain the correct nid. Use the nid from first vmemap page. Link: https://lkml.kernel.org/r/20230913105401.519709-1-usama.arif@bytedance.com Link: https://lkml.kernel.org/r/20230913105401.519709-2-usama.arif@bytedance.comSigned-off-by:
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SeongJae Park authored
The function is used by only mm/damon/core.c. Mark it as a static function. Link: https://lkml.kernel.org/r/20230915025251.72816-9-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
damon_merge_regions_of(), which is called for each aggregation interval, updates nr_accesses_bp to nr_accesses * 10000. However, nr_accesses_bp is updated for each sampling interval via damon_moving_sum() using the aggregation interval as the moving time window. And by the definition of the algorithm, the value becomes same to discrete-window based sum for each time window-aligned time. Hence, nr_accesses_bp will be same to nr_accesses * 10000 for each aggregation interval without explicit update. Remove the unnecessary update of nr_accesses_bp in damon_merge_regions_of(). Link: https://lkml.kernel.org/r/20230915025251.72816-8-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Let nr_accesses_bp be calculated as a pseudo-moving sum that updated for every sampling interval, using damon_moving_sum(). This is assumed to be useful for cases that the aggregation interval is set quite huge, but the monivoting results need to be collected earlier than next aggregation interval is passed. Link: https://lkml.kernel.org/r/20230915025251.72816-7-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Add yet another representation of the access rate of each region, namely nr_accesses_bp. It is just same to the nr_accesses but represents the value in basis point (1 in 10,000), and updated at once in every aggregation interval. That is, moving_accesses_bp is just nr_accesses * 10000. This may seems useless at the moment. However, it will be useful for representing less than one nr_accesses value that will be needed to make moving sum-based nr_accesses. Link: https://lkml.kernel.org/r/20230915025251.72816-6-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Add a simple unit test for the pseudo moving-sum function (damon_moving_sum()). Link: https://lkml.kernel.org/r/20230915025251.72816-5-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
For values that continuously change, moving average or sum are good ways to provide fast updates while handling temporal and errorneous variability of the value. For example, the access rate counter (nr_accesses) is calculated as a sum of the number of positive sampled access check results that collected during a discrete time window (aggregation interval), and hence it handles temporal and errorneous access check results, but provides the update only for every aggregation interval. Using a moving sum method for that could allow providing the value for every sampling interval. That could be useful for getting monitoring results snapshot or running DAMOS in fine-grained timing. However, supporting the moving sum for cases that number of samples in the time window is arbirary could impose high overhead, since the number of past values that it needs to keep could be too high. The nr_accesses would also be one of the cases. To mitigate the overhead, implement a pseudo-moving sum function that only provides an estimated pseudo-moving sum. It assumes there was no error in last discrete time window and subtract constant portion of last discrete time window sum. Note that the function is not strictly implementing the moving sum, but it keeps a property of moving sum, which makes the value same to the dsicrete-window based sum for each time window-aligned timing. Hence, people collecting the value in the old timings would show no difference. Link: https://lkml.kernel.org/r/20230915025251.72816-4-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
When getting mm_struct of the monitoring target process fails, there wil be no need to increase the access rate counter (nr_accesses) of the regions for the process. Hence, damon_va_check_accesses() skips calling damon_update_region_access_rate() in the case. This breaks the assumption that damon_update_region_access_rate() is called for every region, for every sampling interval. Call the function for every region even in the case. This might increase the overhead in some cases, but such case would not be frequent, so no significant impact is really expected. Link: https://lkml.kernel.org/r/20230915025251.72816-3-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Patch series "mm/damon: provide pseudo-moving sum based access rate". DAMON checks the access to each region for every sampling interval, increase the access rate counter of the region, namely nr_accesses, if the access was made. For every aggregation interval, the counter is reset. The counter is exposed to users to be used as a metric showing the relative access rate (frequency) of each region. In other words, DAMON provides access rate of each region in every aggregation interval. The aggregation avoids temporal access pattern changes making things confusing. However, this also makes a few DAMON-related operations to unnecessarily need to be aligned to the aggregation interval. This can restrict the flexibility of DAMON applications, especially when the aggregation interval is huge. To provide the monitoring results in finer-grained timing while keeping handling of temporal access pattern change, this patchset implements a pseudo-moving sum based access rate metric. It is pseudo-moving sum because strict moving sum implementation would need to keep all values for last time window, and that could incur high overhead of there could be arbitrary number of values in a time window. Especially in case of the nr_accesses, since the sampling interval and aggregation interval can arbitrarily set and the past values should be maintained for every region, it could be risky. The pseudo-moving sum assumes there were no temporal access pattern change in last discrete time window to remove the needs for keeping the list of the last time window values. As a result, it beocmes not strict moving sum implementation, but provides a reasonable accuracy. Also, it keeps an important property of the moving sum. That is, the moving sum becomes same to discrete-window based sum at the time that aligns to the time window. This means using the pseudo moving sum based nr_accesses makes no change to users who shows the value for every aggregation interval. Patches Sequence ---------------- The sequence of the patches is as follows. The first four patches are for preparation of the change. The first two (patches 1 and 2) implements a helper function for nr_accesses update and eliminate corner case that skips use of the function, respectively. Following two (patches 3 and 4) respectively implement the pseudo-moving sum function and its simple unit test case. Two patches for making DAMON to use the pseudo-moving sum follow. The fifthe one (patch 5) introduces a new field for representing the pseudo-moving sum-based access rate of each region, and the sixth one makes the new representation to actually updated with the pseudo-moving sum function. Last two patches (patches 7 and 8) makes followup fixes for skipping unnecessary updates and marking the moving sum function as static, respectively. This patch (of 8): Each DAMON operarions set is updating nr_accesses field of each damon_region for each of their access check results, from the check_accesses() callback. Directly accessing the field could make things complex to manage and change in future. Define and use a dedicated function for the purpose. Link: https://lkml.kernel.org/r/20230915025251.72816-1-sj@kernel.org Link: https://lkml.kernel.org/r/20230915025251.72816-2-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
DAMON sleeps for sampling interval after each sampling, and check if the aggregation interval and the ops update interval have passed using ktime_get_coarse_ts64() and baseline timestamps for the intervals. That design is for making the operations occur at deterministic timing regardless of the time that spend for each work. However, it turned out it is not that useful, and incur not-that-intuitive results. After all, timer functions, and especially sleep functions that DAMON uses to wait for specific timing, are not necessarily strictly accurate. It is legal design, so no problem. However, depending on such inaccuracies, the nr_accesses can be larger than aggregation interval divided by sampling interval. For example, with the default setting (5 ms sampling interval and 100 ms aggregation interval) we frequently show regions having nr_accesses larger than 20. Also, if the execution of a DAMOS scheme takes a long time, next aggregation could happen before enough number of samples are collected. This is not what usual users would intuitively expect. Since access check sampling is the smallest unit work of DAMON, using the number of passed sampling intervals as the DAMON-internal timer can easily avoid these problems. That is, convert aggregation and ops update intervals to numbers of sampling intervals that need to be passed before those operations be executed, count the number of passed sampling intervals, and invoke the operations as soon as the specific amount of sampling intervals passed. Make the change. Note that this could make a behavioral change to settings that using intervals that not aligned by the sampling interval. For example, if the sampling interval is 5 ms and the aggregation interval is 12 ms, DAMON effectively uses 15 ms as its aggregation interval, because it checks whether the aggregation interval after sleeping the sampling interval. This change will make DAMON to effectively use 10 ms as aggregation interval, since it uses 'aggregation interval / sampling interval * sampling interval' as the effective aggregation interval, and we don't use floating point types. Usual users would have used aligned intervals, so this behavioral change is not expected to make any meaningful impact, so just make this change. Link: https://lkml.kernel.org/r/20230914021523.60649-1-sj@kernel.orgSigned-off-by:
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Zi Yan authored
__flush_dcache_pages() is called during hugetlb migration via migrate_pages() -> migrate_hugetlbs() -> unmap_and_move_huge_page() -> move_to_new_folio() -> flush_dcache_folio(). And with hugetlb and without sparsemem vmemmap, struct page is not guaranteed to be contiguous beyond a section. Use nth_page() instead. Without the fix, a wrong address might be used for data cache page flush. No bug is reported. The fix comes from code inspection. Link: https://lkml.kernel.org/r/20230913201248.452081-6-zi.yan@sent.com Fixes: 15fa3e8e ("mips: implement the new page table range API") Signed-off-by:
Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: <stable@vger.kernel.org> Signed-off-by:
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Zi Yan authored
When dealing with hugetlb pages, struct page is not guaranteed to be contiguous on SPARSEMEM without VMEMMAP. Use nth_page() to handle it properly. Without the fix, a wrong subpage might be checked for HWPoison, causing wrong number of bytes of a page copied to user space. No bug is reported. The fix comes from code inspection. Link: https://lkml.kernel.org/r/20230913201248.452081-5-zi.yan@sent.com Fixes: 38c1ddbd ("hugetlbfs: improve read HWPOISON hugepage") Signed-off-by:
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Zi Yan authored
When dealing with hugetlb pages, manipulating struct page pointers directly can get to wrong struct page, since struct page is not guaranteed to be contiguous on SPARSEMEM without VMEMMAP. Use pfn calculation to handle it properly. Without the fix, a wrong number of page might be skipped. Since skip cannot be negative, scan_movable_page() will end early and might miss a movable page with -ENOENT. This might fail offline_pages(). No bug is reported. The fix comes from code inspection. Link: https://lkml.kernel.org/r/20230913201248.452081-4-zi.yan@sent.com Fixes: eeb0efd0 ("mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepages") Signed-off-by:
David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: <stable@vger.kernel.org> Signed-off-by:
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Zi Yan authored
When dealing with hugetlb pages, manipulating struct page pointers directly can get to wrong struct page, since struct page is not guaranteed to be contiguous on SPARSEMEM without VMEMMAP. Use nth_page() to handle it properly. A wrong or non-existing page might be tried to be grabbed, either leading to a non freeable page or kernel memory access errors. No bug is reported. It comes from code inspection. Link: https://lkml.kernel.org/r/20230913201248.452081-3-zi.yan@sent.com Fixes: 57a196a5 ("hugetlb: simplify hugetlb handling in follow_page_mask") Signed-off-by:
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Zi Yan authored
Patch series "Use nth_page() in place of direct struct page manipulation", v3. On SPARSEMEM without VMEMMAP, struct page is not guaranteed to be contiguous, since each memory section's memmap might be allocated independently. hugetlb pages can go beyond a memory section size, thus direct struct page manipulation on hugetlb pages/subpages might give wrong struct page. Kernel provides nth_page() to do the manipulation properly. Use that whenever code can see hugetlb pages. This patch (of 5): When dealing with hugetlb pages, manipulating struct page pointers directly can get to wrong struct page, since struct page is not guaranteed to be contiguous on SPARSEMEM without VMEMMAP. Use nth_page() to handle it properly. Without the fix, page_kasan_tag_reset() could reset wrong page tags, causing a wrong kasan result. No related bug is reported. The fix comes from code inspection. Link: https://lkml.kernel.org/r/20230913201248.452081-1-zi.yan@sent.com Link: https://lkml.kernel.org/r/20230913201248.452081-2-zi.yan@sent.com Fixes: 2813b9c0 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc") Signed-off-by:
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Vlastimil Babka authored
This isolate_mode_t flag is effectively unused since 89f6c88a ("mm: __isolate_lru_page_prepare() in isolate_migratepages_block()") as sc->may_unmap is now checked directly (and only node_reclaim has a mode that sets it to 0). The last remaining place is mm_vmscan_lru_isolate tracepoint for the isolate_mode parameter. That one was mainly used to indicate the active/inactive mode, which the trace-vmscan-postprocess.pl script consumed, but that got silently broken. After fixing the script by the previous patch, it does not need the isolate_mode anymore. So just remove the parameter and with that the whole ISOLATE_UNMAPPED flag. Link: https://lkml.kernel.org/r/20230914131637.12204-4-vbabka@suse.czSigned-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
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Vlastimil Babka authored
The script has fallen behind tracepoint changes for a while, fix it up. Most changes are mechanical (renames, removal of tracepoint parameters that are not used by the script). More notable change involves mm_vmscan_lru_isolate which is relying on the isolate_mode to determine if the inactive list is being scanned. However the parameter currently only indicates ISOLATE_UNMAPPED. We can use the lru parameter instead to determine which list is scanned, and stop checking isolate_mode. Link: https://lkml.kernel.org/r/20230914131637.12204-3-vbabka@suse.czSigned-off-by:
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Matthew Wilcox (Oracle) authored
Inline it into __bread_gfp(). Link: https://lkml.kernel.org/r/20230914150011.843330-9-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Most of the callers of sb_getblk_gfp() already assumed that they were passing the entire GFP flags to use. Fix up the two callers that didn't, and remove the __GFP_NOFAIL from them since they both appear to correctly handle failure. Link: https://lkml.kernel.org/r/20230914150011.843330-8-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Now that __getblk() is in the right place in the file, it is trivial to call it from sb_getblk(). Link: https://lkml.kernel.org/r/20230914150011.843330-7-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Move these two functions up in the file for the benefit of the next patch, and pass in all of the GFP flags to use instead of the partial GFP flags used by __getblk_gfp(). Link: https://lkml.kernel.org/r/20230914150011.843330-6-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
__getblk() adds __GFP_NOFAIL, which is unnecessary for readahead; we're quite comfortable with the possibility that we may not get a bh back. Switch to bdev_getblk() which does not include __GFP_NOFAIL. Link: https://lkml.kernel.org/r/20230914150011.843330-5-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
sb_getblk_gfp adds __GFP_NOFAIL, which is unnecessary for readahead; we're quite comfortable with the possibility that we may not get a bh back. Switch to bdev_getblk() which does not include __GFP_NOFAIL. Link: https://lkml.kernel.org/r/20230914150011.843330-4-willy@infradead.orgSigned-off-by:
Hui Zhu <teawater@antgroup.com> Closes: https://lore.kernel.org/linux-fsdevel/20230811035705.3296-1-teawaterz@linux.alibaba.com/Signed-off-by:
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Matthew Wilcox (Oracle) authored
grow_dev_page() is only called by grow_buffers(). grow_buffers() is only called by __getblk_slow() and __getblk_slow() is only called from __getblk_gfp(), so it is safe to move the GFP flags setting all the way up. With that done, add a new bdev_getblk() entry point that leaves the GFP flags the way the caller specified them. [willy@infradead.org: fix grow_dev_page() error handling] Link: https://lkml.kernel.org/r/ZRREEIwqiy5DijKB@casper.infradead.org Link: https://lkml.kernel.org/r/20230914150011.843330-3-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Patch series "Add and use bdev_getblk()", v2. This patch series fixes a bug reported by Hui Zhu; see proposed patches v1 and v2: https://lore.kernel.org/linux-fsdevel/20230811035705.3296-1-teawaterz@linux.alibaba.com/ https://lore.kernel.org/linux-fsdevel/20230811071519.1094-1-teawaterz@linux.alibaba.com/ I decided to go in a rather different direction for this fix, and fix a related problem at the same time. I don't think there's any urgency to rush this into Linus' tree, nor have I marked it for stable. Reasonable people may disagree. This patch (of 8): Instead of creating entirely new flags, inherit them from grow_dev_page(). The other callers create the same flags that this function used to create. Link: https://lkml.kernel.org/r/20230914150011.843330-1-willy@infradead.org Link: https://lkml.kernel.org/r/20230914150011.843330-2-willy@infradead.orgSigned-off-by:
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SeongJae Park authored
Document damos_before_apply tracepoint on the usage document. Link: https://lkml.kernel.org/r/20230913022050.2109-3-sj@kernel.orgSigned-off-by:
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SeongJae Park authored
Patch series "mm/damon: add a tracepoint for damos apply target regions", v2. DAMON provides damon_aggregated tracepoint to let users record full monitoring results. Sometimes, users need to record monitoring results of specific pattern. DAMOS tried regions directory of DAMON sysfs interface allows it, but the interface is mainly designed for snapshots and therefore would be inefficient for such recording. Implement yet another tracepoint for efficient support of the usecase. This patch (of 2): DAMON provides damon_aggregated tracepoint, which exposes details of each region and its access monitoring results. It is useful for getting whole monitoring results, e.g., for recording purposes. For investigations of DAMOS, DAMON Sysfs interface provides DAMOS statistics and tried_regions directory. But, those provides only statistics and snapshots. If the scheme is frequently applied and if the user needs to know every detail of DAMOS behavior, the snapshot-based interface could be insufficient and expensive. As a last resort, userspace users need to record the all monitoring results via damon_aggregated tracepoint and simulate how DAMOS would worked. It is unnecessarily complicated. DAMON kernel API users, meanwhile, can do that easily via before_damos_apply() callback field of 'struct damon_callback', though. Add a tracepoint that will be called just after before_damos_apply() callback for more convenient investigations of DAMOS. The tracepoint exposes all details about each regions, similar to damon_aggregated tracepoint. Please note that DAMOS is currently not only for memory management but also for query-like efficient monitoring results retrievals (when 'stat' action is used). Until now, only statistics or snapshots were supported. Addition of this tracepoint allows efficient full recording of DAMOS-based filtered monitoring results. Link: https://lkml.kernel.org/r/20230913022050.2109-1-sj@kernel.org Link: https://lkml.kernel.org/r/20230913022050.2109-2-sj@kernel.orgSigned-off-by:
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Kefeng Wang authored
Directly check the return of isolate_hugetlb() and folio_isolate_lru() to remove isolated variable, also setup err = -EBUSY in advance before isolation, and update err only when successfully queued for migration, which could help us to unify and simplify code a bit. Link: https://lkml.kernel.org/r/20230913095131.2426871-9-wangkefeng.wang@huawei.comSigned-off-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by:
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Kefeng Wang authored
There is some different between hugeTLB and THP behave when passed the address of a tail page, for THP, it will migrate the entire THP page, but for HugeTLB, it will return -EACCES, or -ENOENT before commit e66f17ff ("mm/hugetlb: take page table lock in follow_huge_pmd()"), -EACCES The page is mapped by multiple processes and can be moved only if MPOL_MF_MOVE_ALL is specified. -ENOENT The page is not present. But when check manual[1], both of the two errnos are not suitable, it is better to keep the same behave between hugetlb and THP when passed the address of a tail page, so let's just remove the PageHead() check for HugeTLB. [1] https://man7.org/linux/man-pages/man2/move_pages.2.html Link: https://lkml.kernel.org/r/20230913095131.2426871-8-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Use a folio in add_page_for_migration() to save compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-7-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Use __folio_test_movable(), no need to convert from folio to page again. Link: https://lkml.kernel.org/r/20230913095131.2426871-6-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
At present, numa balance only support base page and PMD-mapped THP, but we will expand to support to migrate large folio/pte-mapped THP in the future, it is better to make migrate_misplaced_page() to take a folio instead of a page, and rename it to migrate_misplaced_folio(), it is a preparation, also this remove several compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-5-wangkefeng.wang@huawei.comSigned-off-by:
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Kefeng Wang authored
Rename numamigrate_isolate_page() to numamigrate_isolate_folio(), then make it takes a folio and use folio API to save compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-4-wangkefeng.wang@huawei.comSigned-off-by:
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