- 15 4月, 2015 3 次提交
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由 David Rientjes 提交于
Commit 077fcf11 ("mm/thp: allocate transparent hugepages on local node") restructured alloc_hugepage_vma() with the intent of only allocating transparent hugepages locally when there was not an effective interleave mempolicy. alloc_pages_exact_node() does not limit the allocation to the single node, however, but rather prefers it. This is because __GFP_THISNODE is not set which would cause the node-local nodemask to be passed. Without it, only a nodemask that prefers the local node is passed. Fix this by passing __GFP_THISNODE and falling back to small pages when the allocation fails. Commit 9f1b868a ("mm: thp: khugepaged: add policy for finding target node") suffers from a similar problem for khugepaged, which is also fixed. Fixes: 077fcf11 ("mm/thp: allocate transparent hugepages on local node") Fixes: 9f1b868a ("mm: thp: khugepaged: add policy for finding target node") Signed-off-by: NDavid Rientjes <rientjes@google.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Pravin Shelar <pshelar@nicira.com> Cc: Jarno Rajahalme <jrajahalme@nicira.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Greg Thelen <gthelen@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ebru Akagunduz 提交于
This patch improves THP collapse rates, by allowing zero pages. Currently THP can collapse 4kB pages into a THP when there are up to khugepaged_max_ptes_none pte_none ptes in a 2MB range. This patch counts pte none and mapped zero pages with the same variable. The patch was tested with a program that allocates 800MB of memory, and performs interleaved reads and writes, in a pattern that causes some 2MB areas to first see read accesses, resulting in the zero pfn being mapped there. To simulate memory fragmentation at allocation time, I modified do_huge_pmd_anonymous_page to return VM_FAULT_FALLBACK for read faults. Without the patch, only %50 of the program was collapsed into THP and the percentage did not increase over time. With this patch after 10 minutes of waiting khugepaged had collapsed %99 of the program's memory. [aarcange@redhat.com: fix bogus BUG()] Signed-off-by: NEbru Akagunduz <ebru.akagunduz@gmail.com> Reviewed-by: NRik van Riel <riel@redhat.com> Reviewed-by: NAndrea Arcangeli <aarcange@redhat.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
After commit a1fde08c ("VM: skip the stack guard page lookup in get_user_pages only for mlock") FOLL_MLOCK has lost its original meaning: we don't necessarily mlock the page if the flags is set -- we also take VM_LOCKED into consideration. Since we use the same codepath for __mm_populate(), let's rename FOLL_MLOCK to FOLL_POPULATE. Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Acked-by: NDavid Rientjes <rientjes@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 3月, 2015 4 次提交
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由 Mel Gorman 提交于
Base PTEs are marked young when the NUMA hinting information is cleared but the same does not happen for huge pages which this patch addresses. Note that migrated pages are not marked young as the base page migration code does not assume that migrated pages have been referenced. This could be addressed but beyond the scope of this series which is aimed at Dave Chinners shrink workload that is unlikely to be affected by this issue. Signed-off-by: NMel Gorman <mgorman@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Dave Chinner reported the following on https://lkml.org/lkml/2015/3/1/226 Across the board the 4.0-rc1 numbers are much slower, and the degradation is far worse when using the large memory footprint configs. Perf points straight at the cause - this is from 4.0-rc1 on the "-o bhash=101073" config: - 56.07% 56.07% [kernel] [k] default_send_IPI_mask_sequence_phys - default_send_IPI_mask_sequence_phys - 99.99% physflat_send_IPI_mask - 99.37% native_send_call_func_ipi smp_call_function_many - native_flush_tlb_others - 99.85% flush_tlb_page ptep_clear_flush try_to_unmap_one rmap_walk try_to_unmap migrate_pages migrate_misplaced_page - handle_mm_fault - 99.73% __do_page_fault trace_do_page_fault do_async_page_fault + async_page_fault 0.63% native_send_call_func_single_ipi generic_exec_single smp_call_function_single This is showing excessive migration activity even though excessive migrations are meant to get throttled. Normally, the scan rate is tuned on a per-task basis depending on the locality of faults. However, if migrations fail for any reason then the PTE scanner may scan faster if the faults continue to be remote. This means there is higher system CPU overhead and fault trapping at exactly the time we know that migrations cannot happen. This patch tracks when migration failures occur and slows the PTE scanner. Signed-off-by: NMel Gorman <mgorman@suse.de> Reported-by: NDave Chinner <david@fromorbit.com> Tested-by: NDave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Protecting a PTE to trap a NUMA hinting fault clears the writable bit and further faults are needed after trapping a NUMA hinting fault to set the writable bit again. This patch preserves the writable bit when trapping NUMA hinting faults. The impact is obvious from the number of minor faults trapped during the basis balancing benchmark and the system CPU usage; autonumabench 4.0.0-rc4 4.0.0-rc4 baseline preserve Time System-NUMA01 107.13 ( 0.00%) 103.13 ( 3.73%) Time System-NUMA01_THEADLOCAL 131.87 ( 0.00%) 83.30 ( 36.83%) Time System-NUMA02 8.95 ( 0.00%) 10.72 (-19.78%) Time System-NUMA02_SMT 4.57 ( 0.00%) 3.99 ( 12.69%) Time Elapsed-NUMA01 515.78 ( 0.00%) 517.26 ( -0.29%) Time Elapsed-NUMA01_THEADLOCAL 384.10 ( 0.00%) 384.31 ( -0.05%) Time Elapsed-NUMA02 48.86 ( 0.00%) 48.78 ( 0.16%) Time Elapsed-NUMA02_SMT 47.98 ( 0.00%) 48.12 ( -0.29%) 4.0.0-rc4 4.0.0-rc4 baseline preserve User 44383.95 43971.89 System 252.61 201.24 Elapsed 998.68 1000.94 Minor Faults 2597249 1981230 Major Faults 365 364 There is a similar drop in system CPU usage using Dave Chinner's xfsrepair workload 4.0.0-rc4 4.0.0-rc4 baseline preserve Amean real-xfsrepair 454.14 ( 0.00%) 442.36 ( 2.60%) Amean syst-xfsrepair 277.20 ( 0.00%) 204.68 ( 26.16%) The patch looks hacky but the alternatives looked worse. The tidest was to rewalk the page tables after a hinting fault but it was more complex than this approach and the performance was worse. It's not generally safe to just mark the page writable during the fault if it's a write fault as it may have been read-only for COW so that approach was discarded. Signed-off-by: NMel Gorman <mgorman@suse.de> Reported-by: NDave Chinner <david@fromorbit.com> Tested-by: NDave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
These are three follow-on patches based on the xfsrepair workload Dave Chinner reported was problematic in 4.0-rc1 due to changes in page table management -- https://lkml.org/lkml/2015/3/1/226. Much of the problem was reduced by commit 53da3bc2 ("mm: fix up numa read-only thread grouping logic") and commit ba68bc01 ("mm: thp: Return the correct value for change_huge_pmd"). It was known that the performance in 3.19 was still better even if is far less safe. This series aims to restore the performance without compromising on safety. For the test of this mail, I'm comparing 3.19 against 4.0-rc4 and the three patches applied on top autonumabench 3.19.0 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 vanilla vanilla vmwrite-v5r8 preserve-v5r8 slowscan-v5r8 Time System-NUMA01 124.00 ( 0.00%) 161.86 (-30.53%) 107.13 ( 13.60%) 103.13 ( 16.83%) 145.01 (-16.94%) Time System-NUMA01_THEADLOCAL 115.54 ( 0.00%) 107.64 ( 6.84%) 131.87 (-14.13%) 83.30 ( 27.90%) 92.35 ( 20.07%) Time System-NUMA02 9.35 ( 0.00%) 10.44 (-11.66%) 8.95 ( 4.28%) 10.72 (-14.65%) 8.16 ( 12.73%) Time System-NUMA02_SMT 3.87 ( 0.00%) 4.63 (-19.64%) 4.57 (-18.09%) 3.99 ( -3.10%) 3.36 ( 13.18%) Time Elapsed-NUMA01 570.06 ( 0.00%) 567.82 ( 0.39%) 515.78 ( 9.52%) 517.26 ( 9.26%) 543.80 ( 4.61%) Time Elapsed-NUMA01_THEADLOCAL 393.69 ( 0.00%) 384.83 ( 2.25%) 384.10 ( 2.44%) 384.31 ( 2.38%) 380.73 ( 3.29%) Time Elapsed-NUMA02 49.09 ( 0.00%) 49.33 ( -0.49%) 48.86 ( 0.47%) 48.78 ( 0.63%) 50.94 ( -3.77%) Time Elapsed-NUMA02_SMT 47.51 ( 0.00%) 47.15 ( 0.76%) 47.98 ( -0.99%) 48.12 ( -1.28%) 49.56 ( -4.31%) 3.19.0 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 vanilla vanillavmwrite-v5r8preserve-v5r8slowscan-v5r8 User 46334.60 46391.94 44383.95 43971.89 44372.12 System 252.84 284.66 252.61 201.24 249.00 Elapsed 1062.14 1050.96 998.68 1000.94 1026.78 Overall the system CPU usage is comparable and the test is naturally a bit variable. The slowing of the scanner hurts numa01 but on this machine it is an adverse workload and patches that dramatically help it often hurt absolutely everything else. Due to patch 2, the fault activity is interesting 3.19.0 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 vanilla vanillavmwrite-v5r8preserve-v5r8slowscan-v5r8 Minor Faults 2097811 2656646 2597249 1981230 1636841 Major Faults 362 450 365 364 365 Note the impact preserving the write bit across protection updates and fault reduces faults. NUMA alloc hit 1229008 1217015 1191660 1178322 1199681 NUMA alloc miss 0 0 0 0 0 NUMA interleave hit 0 0 0 0 0 NUMA alloc local 1228514 1216317 1190871 1177448 1199021 NUMA base PTE updates 245706197 240041607 238195516 244704842 115012800 NUMA huge PMD updates 479530 468448 464868 477573 224487 NUMA page range updates 491225557 479886983 476207932 489222218 229950144 NUMA hint faults 659753 656503 641678 656926 294842 NUMA hint local faults 381604 373963 360478 337585 186249 NUMA hint local percent 57 56 56 51 63 NUMA pages migrated 5412140 6374899 6266530 5277468 5755096 AutoNUMA cost 5121% 5083% 4994% 5097% 2388% Here the impact of slowing the PTE scanner on migratrion failures is obvious as "NUMA base PTE updates" and "NUMA huge PMD updates" are massively reduced even though the headline performance is very similar. As xfsrepair was the reported workload here is the impact of the series on it. xfsrepair 3.19.0 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 vanilla vanilla vmwrite-v5r8 preserve-v5r8 slowscan-v5r8 Min real-fsmark 1183.29 ( 0.00%) 1165.73 ( 1.48%) 1152.78 ( 2.58%) 1153.64 ( 2.51%) 1177.62 ( 0.48%) Min syst-fsmark 4107.85 ( 0.00%) 4027.75 ( 1.95%) 3986.74 ( 2.95%) 3979.16 ( 3.13%) 4048.76 ( 1.44%) Min real-xfsrepair 441.51 ( 0.00%) 463.96 ( -5.08%) 449.50 ( -1.81%) 440.08 ( 0.32%) 439.87 ( 0.37%) Min syst-xfsrepair 195.76 ( 0.00%) 278.47 (-42.25%) 262.34 (-34.01%) 203.70 ( -4.06%) 143.64 ( 26.62%) Amean real-fsmark 1188.30 ( 0.00%) 1177.34 ( 0.92%) 1157.97 ( 2.55%) 1158.21 ( 2.53%) 1182.22 ( 0.51%) Amean syst-fsmark 4111.37 ( 0.00%) 4055.70 ( 1.35%) 3987.19 ( 3.02%) 3998.72 ( 2.74%) 4061.69 ( 1.21%) Amean real-xfsrepair 450.88 ( 0.00%) 468.32 ( -3.87%) 454.14 ( -0.72%) 442.36 ( 1.89%) 440.59 ( 2.28%) Amean syst-xfsrepair 199.66 ( 0.00%) 290.60 (-45.55%) 277.20 (-38.84%) 204.68 ( -2.51%) 150.55 ( 24.60%) Stddev real-fsmark 4.12 ( 0.00%) 10.82 (-162.29%) 4.14 ( -0.28%) 5.98 (-45.05%) 4.60 (-11.53%) Stddev syst-fsmark 2.63 ( 0.00%) 20.32 (-671.82%) 0.37 ( 85.89%) 16.47 (-525.59%) 15.05 (-471.79%) Stddev real-xfsrepair 6.87 ( 0.00%) 4.55 ( 33.75%) 3.46 ( 49.58%) 1.78 ( 74.12%) 0.52 ( 92.50%) Stddev syst-xfsrepair 3.02 ( 0.00%) 10.30 (-241.37%) 13.17 (-336.37%) 0.71 ( 76.63%) 5.00 (-65.61%) CoeffVar real-fsmark 0.35 ( 0.00%) 0.92 (-164.73%) 0.36 ( -2.91%) 0.52 (-48.82%) 0.39 (-12.10%) CoeffVar syst-fsmark 0.06 ( 0.00%) 0.50 (-682.41%) 0.01 ( 85.45%) 0.41 (-543.22%) 0.37 (-478.78%) CoeffVar real-xfsrepair 1.52 ( 0.00%) 0.97 ( 36.21%) 0.76 ( 49.94%) 0.40 ( 73.62%) 0.12 ( 92.33%) CoeffVar syst-xfsrepair 1.51 ( 0.00%) 3.54 (-134.54%) 4.75 (-214.31%) 0.34 ( 77.20%) 3.32 (-119.63%) Max real-fsmark 1193.39 ( 0.00%) 1191.77 ( 0.14%) 1162.90 ( 2.55%) 1166.66 ( 2.24%) 1188.50 ( 0.41%) Max syst-fsmark 4114.18 ( 0.00%) 4075.45 ( 0.94%) 3987.65 ( 3.08%) 4019.45 ( 2.30%) 4082.80 ( 0.76%) Max real-xfsrepair 457.80 ( 0.00%) 474.60 ( -3.67%) 457.82 ( -0.00%) 444.42 ( 2.92%) 441.03 ( 3.66%) Max syst-xfsrepair 203.11 ( 0.00%) 303.65 (-49.50%) 294.35 (-44.92%) 205.33 ( -1.09%) 155.28 ( 23.55%) The really relevant lines as syst-xfsrepair which is the system CPU usage when running xfsrepair. Note that on my machine the overhead was 45% higher on 4.0-rc4 which may be part of what Dave is seeing. Once we preserve the write bit across faults, it's only 2.51% higher on average. With the full series applied, system CPU usage is 24.6% lower on average. Again, the impact of preserving the write bit on minor faults is obvious and the impact of slowing scanning after migration failures is obvious on the PTE updates. Note also that the number of pages migrated is much reduced even though the headline performance is comparable. 3.19.0 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 vanilla vanillavmwrite-v5r8preserve-v5r8slowscan-v5r8 Minor Faults 153466827 254507978 249163829 153501373 105737890 Major Faults 610 702 690 649 724 NUMA base PTE updates 217735049 210756527 217729596 216937111 144344993 NUMA huge PMD updates 129294 85044 106921 127246 79887 NUMA pages migrated 21938995 29705270 28594162 22687324 16258075 3.19.0 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 4.0.0-rc4 vanilla vanillavmwrite-v5r8preserve-v5r8slowscan-v5r8 Mean sdb-avgqusz 13.47 2.54 2.55 2.47 2.49 Mean sdb-avgrqsz 202.32 140.22 139.50 139.02 138.12 Mean sdb-await 25.92 5.09 5.33 5.02 5.22 Mean sdb-r_await 4.71 0.19 0.83 0.51 0.11 Mean sdb-w_await 104.13 5.21 5.38 5.05 5.32 Mean sdb-svctm 0.59 0.13 0.14 0.13 0.14 Mean sdb-rrqm 0.16 0.00 0.00 0.00 0.00 Mean sdb-wrqm 3.59 1799.43 1826.84 1812.21 1785.67 Max sdb-avgqusz 111.06 12.13 14.05 11.66 15.60 Max sdb-avgrqsz 255.60 190.34 190.01 187.33 191.78 Max sdb-await 168.24 39.28 49.22 44.64 65.62 Max sdb-r_await 660.00 52.00 280.00 76.00 12.00 Max sdb-w_await 7804.00 39.28 49.22 44.64 65.62 Max sdb-svctm 4.00 2.82 2.86 1.98 2.84 Max sdb-rrqm 8.30 0.00 0.00 0.00 0.00 Max sdb-wrqm 34.20 5372.80 5278.60 5386.60 5546.15 FWIW, I also checked SPECjbb in different configurations but it's similar observations -- minor faults lower, PTE update activity lower and performance is roughly comparable against 3.19. This patch (of 3): Threads that share writable data within pages are grouped together as related tasks. This decision is based on whether the PTE is marked dirty which is subject to timing races between the PTE scanner update and when the application writes the page. If the page is file-backed, then background flushes and sync also affect placement. This is unpredictable behaviour which is impossible to reason about so this patch makes grouping decisions based on the VMA flags. Signed-off-by: NMel Gorman <mgorman@suse.de> Reported-by: NDave Chinner <david@fromorbit.com> Tested-by: NDave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 3月, 2015 1 次提交
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由 Mel Gorman 提交于
The wrong value is being returned by change_huge_pmd since commit 10c1045f ("mm: numa: avoid unnecessary TLB flushes when setting NUMA hinting entries") which allows a fallthrough that tries to adjust non-existent PTEs. This patch corrects it. Signed-off-by: NMel Gorman <mgorman@suse.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 12 3月, 2015 1 次提交
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由 Linus Torvalds 提交于
Dave Chinner reported that commit 4d942466 ("mm: convert p[te|md]_mknonnuma and remaining page table manipulations") slowed down his xfsrepair test enormously. In particular, it was using more system time due to extra TLB flushing. The ultimate reason turns out to be how the change to use the regular page table accessor functions broke the NUMA grouping logic. The old special mknuma/mknonnuma code accessed the page table present bit and the magic NUMA bit directly, while the new code just changes the page protections using PROT_NONE and the regular vma protections. That sounds equivalent, and from a fault standpoint it really is, but a subtle side effect is that the *other* protection bits of the page table entries also change. And the code to decide how to group the NUMA entries together used the writable bit to decide whether a particular page was likely to be shared read-only or not. And with the change to make the NUMA handling use the regular permission setting functions, that writable bit was basically always cleared for private mappings due to COW. So even if the page actually ends up being written to in the end, the NUMA balancing would act as if it was always shared RO. This code is a heuristic anyway, so the fix - at least for now - is to instead check whether the page is dirty rather than writable. The bit doesn't change with protection changes. NOTE! This also adds a FIXME comment to revisit this issue, Not only should we probably re-visit the whole "is this a shared read-only page" heuristic (we might want to take the vma permissions into account and base this more on those than the per-page ones, and also look at whether the particular access that triggers it is a write or not), but the whole COW issue shows that we should think about the NUMA fault handling some more. For example, maybe we should do the early-COW thing that a regular fault does. Or maybe we should accept that while using the same bits as PROTNONE was a good thing (and got rid of the specual NUMA bit), we might still want to just preseve the other protection bits across NUMA faulting. Those are bigger questions, left for later. This just fixes up the heuristic so that it at least approximates working again. More analysis and work needed. Reported-by: NDave Chinner <david@fromorbit.com> Tested-by: NMel Gorman <mgorman@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org>, Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 2月, 2015 6 次提交
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由 Mel Gorman 提交于
If a PTE or PMD is already marked NUMA when scanning to mark entries for NUMA hinting then it is not necessary to update the entry and incur a TLB flush penalty. Avoid the avoidhead where possible. Signed-off-by: NMel Gorman <mgorman@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
pte_protnone_numa is only safe to use after VMA checks for PROT_NONE are complete. Treating a real PROT_NONE PTE as a NUMA hinting fault is going to result in strangeness so add a check for it. BUG_ON looks like overkill but if this is hit then it's a serious bug that could result in corruption so do not even try recovering. It would have been more comprehensive to check VMA flags in pte_protnone_numa but it would have made the API ugly just for a debugging check. Signed-off-by: NMel Gorman <mgorman@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Faults on the huge zero page are pointless and there is a BUG_ON to catch them during fault time. This patch reintroduces a check that avoids marking the zero page PAGE_NONE. Signed-off-by: NMel Gorman <mgorman@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
With PROT_NONE, the traditional page table manipulation functions are sufficient. [andre.przywara@arm.com: fix compiler warning in pmdp_invalidate()] [akpm@linux-foundation.org: fix build with STRICT_MM_TYPECHECKS] Signed-off-by: NMel Gorman <mgorman@suse.de> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Acked-by: NAneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Tested-by: NSasha Levin <sasha.levin@oracle.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Convert existing users of pte_numa and friends to the new helper. Note that the kernel is broken after this patch is applied until the other page table modifiers are also altered. This patch layout is to make review easier. Signed-off-by: NMel Gorman <mgorman@suse.de> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Acked-by: NAneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: NSasha Levin <sasha.levin@oracle.com> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Automatic NUMA balancing depends on being able to protect PTEs to trap a fault and gather reference locality information. Very broadly speaking it would mark PTEs as not present and use another bit to distinguish between NUMA hinting faults and other types of faults. It was universally loved by everybody and caused no problems whatsoever. That last sentence might be a lie. This series is very heavily based on patches from Linus and Aneesh to replace the existing PTE/PMD NUMA helper functions with normal change protections. I did alter and add parts of it but I consider them relatively minor contributions. At their suggestion, acked-bys are in there but I've no problem converting them to Signed-off-by if requested. AFAIK, this has received no testing on ppc64 and I'm depending on Aneesh for that. I tested trinity under kvm-tool and passed and ran a few other basic tests. At the time of writing, only the short-lived tests have completed but testing of V2 indicated that long-term testing had no surprises. In most cases I'm leaving out detail as it's not that interesting. specjbb single JVM: There was negligible performance difference in the benchmark itself for short runs. However, system activity is higher and interrupts are much higher over time -- possibly TLB flushes. Migrations are also higher. Overall, this is more overhead but considering the problems faced with the old approach I think we just have to suck it up and find another way of reducing the overhead. specjbb multi JVM: Negligible performance difference to the actual benchmark but like the single JVM case, the system overhead is noticeably higher. Again, interrupts are a major factor. autonumabench: This was all over the place and about all that can be reasonably concluded is that it's different but not necessarily better or worse. autonumabench 3.18.0-rc5 3.18.0-rc5 mmotm-20141119 protnone-v3r3 User NUMA01 32380.24 ( 0.00%) 21642.92 ( 33.16%) User NUMA01_THEADLOCAL 22481.02 ( 0.00%) 22283.22 ( 0.88%) User NUMA02 3137.00 ( 0.00%) 3116.54 ( 0.65%) User NUMA02_SMT 1614.03 ( 0.00%) 1543.53 ( 4.37%) System NUMA01 322.97 ( 0.00%) 1465.89 (-353.88%) System NUMA01_THEADLOCAL 91.87 ( 0.00%) 49.32 ( 46.32%) System NUMA02 37.83 ( 0.00%) 14.61 ( 61.38%) System NUMA02_SMT 7.36 ( 0.00%) 7.45 ( -1.22%) Elapsed NUMA01 716.63 ( 0.00%) 599.29 ( 16.37%) Elapsed NUMA01_THEADLOCAL 553.98 ( 0.00%) 539.94 ( 2.53%) Elapsed NUMA02 83.85 ( 0.00%) 83.04 ( 0.97%) Elapsed NUMA02_SMT 86.57 ( 0.00%) 79.15 ( 8.57%) CPU NUMA01 4563.00 ( 0.00%) 3855.00 ( 15.52%) CPU NUMA01_THEADLOCAL 4074.00 ( 0.00%) 4136.00 ( -1.52%) CPU NUMA02 3785.00 ( 0.00%) 3770.00 ( 0.40%) CPU NUMA02_SMT 1872.00 ( 0.00%) 1959.00 ( -4.65%) System CPU usage of NUMA01 is worse but it's an adverse workload on this machine so I'm reluctant to conclude that it's a problem that matters. On the other workloads that are sensible on this machine, system CPU usage is great. Overall time to complete the benchmark is comparable 3.18.0-rc5 3.18.0-rc5 mmotm-20141119protnone-v3r3 User 59612.50 48586.44 System 460.22 1537.45 Elapsed 1442.20 1304.29 NUMA alloc hit 5075182 5743353 NUMA alloc miss 0 0 NUMA interleave hit 0 0 NUMA alloc local 5075174 5743339 NUMA base PTE updates 637061448 443106883 NUMA huge PMD updates 1243434 864747 NUMA page range updates 1273699656 885857347 NUMA hint faults 1658116 1214277 NUMA hint local faults 959487 754113 NUMA hint local percent 57 62 NUMA pages migrated 5467056 61676398 The NUMA pages migrated look terrible but when I looked at a graph of the activity over time I see that the massive spike in migration activity was during NUMA01. This correlates with high system CPU usage and could be simply down to bad luck but any modifications that affect that workload would be related to scan rates and migrations, not the protection mechanism. For all other workloads, migration activity was comparable. Overall, headline performance figures are comparable but the overhead is higher, mostly in interrupts. To some extent, higher overhead from this approach was anticipated but not to this degree. It's going to be necessary to reduce this again with a separate series in the future. It's still worth going ahead with this series though as it's likely to avoid constant headaches with Xen and is probably easier to maintain. This patch (of 10): A transhuge NUMA hinting fault may find the page is migrating and should wait until migration completes. The check is race-prone because the pmd is deferenced outside of the page lock and while the race is tiny, it'll be larger if the PMD is cleared while marking PMDs for hinting fault. This patch closes the race. Signed-off-by: NMel Gorman <mgorman@suse.de> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 12 2月, 2015 4 次提交
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由 Ebru Akagunduz 提交于
This patch aims to improve THP collapse rates, by allowing THP collapse in the presence of read-only ptes, like those left in place by do_swap_page after a read fault. Currently THP can collapse 4kB pages into a THP when there are up to khugepaged_max_ptes_none pte_none ptes in a 2MB range. This patch applies the same limit for read-only ptes. The patch was tested with a test program that allocates 800MB of memory, writes to it, and then sleeps. I force the system to swap out all but 190MB of the program by touching other memory. Afterwards, the test program does a mix of reads and writes to its memory, and the memory gets swapped back in. Without the patch, only the memory that did not get swapped out remained in THPs, which corresponds to 24% of the memory of the program. The percentage did not increase over time. With this patch, after 5 minutes of waiting khugepaged had collapsed 50% of the program's memory back into THPs. Test results: With the patch: After swapped out: cat /proc/pid/smaps: Anonymous: 100464 kB AnonHugePages: 100352 kB Swap: 699540 kB Fraction: 99,88 cat /proc/meminfo: AnonPages: 1754448 kB AnonHugePages: 1716224 kB Fraction: 97,82 After swapped in: In a few seconds: cat /proc/pid/smaps: Anonymous: 800004 kB AnonHugePages: 145408 kB Swap: 0 kB Fraction: 18,17 cat /proc/meminfo: AnonPages: 2455016 kB AnonHugePages: 1761280 kB Fraction: 71,74 In 5 minutes: cat /proc/pid/smaps Anonymous: 800004 kB AnonHugePages: 407552 kB Swap: 0 kB Fraction: 50,94 cat /proc/meminfo: AnonPages: 2456872 kB AnonHugePages: 2023424 kB Fraction: 82,35 Without the patch: After swapped out: cat /proc/pid/smaps: Anonymous: 190660 kB AnonHugePages: 190464 kB Swap: 609344 kB Fraction: 99,89 cat /proc/meminfo: AnonPages: 1740456 kB AnonHugePages: 1667072 kB Fraction: 95,78 After swapped in: cat /proc/pid/smaps: Anonymous: 800004 kB AnonHugePages: 190464 kB Swap: 0 kB Fraction: 23,80 cat /proc/meminfo: AnonPages: 2350032 kB AnonHugePages: 1667072 kB Fraction: 70,93 I waited 10 minutes the fractions did not change without the patch. Signed-off-by: NEbru Akagunduz <ebru.akagunduz@gmail.com> Reviewed-by: NRik van Riel <riel@redhat.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Acked-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: NAndrea Arcangeli <aarcange@redhat.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Naoya Horiguchi 提交于
This patch makes do_mincore() use walk_page_vma(), which reduces many lines of code by using common page table walk code. [daeseok.youn@gmail.com: remove unneeded variable 'err'] Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: NDaeseok Youn <daeseok.youn@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Aneesh Kumar K.V 提交于
This make sure that we try to allocate hugepages from local node if allowed by mempolicy. If we can't, we fallback to small page allocation based on mempolicy. This is based on the observation that allocating pages on local node is more beneficial than allocating hugepages on remote node. With this patch applied we may find transparent huge page allocation failures if the current node doesn't have enough freee hugepages. Before this patch such failures result in us retrying the allocation on other nodes in the numa node mask. [akpm@linux-foundation.org: fix comment, add CONFIG_TRANSPARENT_HUGEPAGE dependency] Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Wang, Yalin 提交于
Add KPF_ZERO_PAGE flag for zero_page, so that userspace processes can detect zero_page in /proc/kpageflags, and then do memory analysis more accurately. Signed-off-by: NYalin Wang <yalin.wang@sonymobile.com> Acked-by: NKirill A. Shutemov <kirill@shutemov.name> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 12月, 2014 1 次提交
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由 Kirill A. Shutemov 提交于
Zero pages can be used only in anonymous mappings, which never have writable vma->vm_page_prot: see protection_map in mm/mmap.c and __PX1X definitions. Let's drop redundant pmd_wrprotect() in set_huge_zero_page(). Signed-off-by: N"Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 30 10月, 2014 2 次提交
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由 David Rientjes 提交于
If an anonymous mapping is not allowed to fault thp memory and then madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never collapse this memory into thp memory. This occurs because the madvise(2) handler for thp, hugepage_madvise(), clears VM_NOHUGEPAGE on the stack and it isn't stored in vma->vm_flags until the final action of madvise_behavior(). This causes the khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when the vma had previously had VM_NOHUGEPAGE set. Fix this by passing the correct vma flags to the khugepaged mm slot handler. There's no chance khugepaged can run on this vma until after madvise_behavior() returns since we hold mm->mmap_sem. It would be possible to clear VM_NOHUGEPAGE directly from vma->vm_flags in hugepage_advise(), but I didn't want to introduce special case behavior into madvise_behavior(). I think it's best to just let it always set vma->vm_flags itself. Signed-off-by: NDavid Rientjes <rientjes@google.com> Reported-by: NSuleiman Souhlal <suleiman@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Yu Zhao 提交于
Compound page should be freed by put_page() or free_pages() with correct order. Not doing so will cause tail pages leaked. The compound order can be obtained by compound_order() or use HPAGE_PMD_ORDER in our case. Some people would argue the latter is faster but I prefer the former which is more general. This bug was observed not just on our servers (the worst case we saw is 11G leaked on a 48G machine) but also on our workstations running Ubuntu based distro. $ cat /proc/vmstat | grep thp_zero_page_alloc thp_zero_page_alloc 55 thp_zero_page_alloc_failed 0 This means there is (thp_zero_page_alloc - 1) * (2M - 4K) memory leaked. Fixes: 97ae1749 ("thp: implement refcounting for huge zero page") Signed-off-by: NYu Zhao <yuzhao@google.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Rientjes <rientjes@google.com> Cc: Bob Liu <lliubbo@gmail.com> Cc: <stable@vger.kernel.org> [3.8+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 10月, 2014 2 次提交
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由 Martin Schwidefsky 提交于
Analog to ptep_get_and_clear_full define a variant of the pmpd_get_and_clear primitive which gets the full hint from the mmu_gather struct. This allows s390 to avoid a costly instruction when destroying an address space. Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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由 Dominik Dingel 提交于
Add a new function stub to allow architectures to disable for an mm_structthe backing of non-present, anonymous pages with read-only empty zero pages. Signed-off-by: NDominik Dingel <dingel@linux.vnet.ibm.com> Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 10 10月, 2014 3 次提交
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由 Sasha Levin 提交于
Dump the contents of the relevant struct_mm when we hit the bug condition. Signed-off-by: NSasha Levin <sasha.levin@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Sasha Levin 提交于
Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract more information when they trigger. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NSasha Levin <sasha.levin@oracle.com> Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Vlastimil Babka 提交于
When allocating huge page for collapsing, khugepaged currently holds mmap_sem for reading on the mm where collapsing occurs. Afterwards the read lock is dropped before write lock is taken on the same mmap_sem. Holding mmap_sem during whole huge page allocation is therefore useless, the vma needs to be rechecked after taking the write lock anyway. Furthemore, huge page allocation might involve a rather long sync compaction, and thus block any mmap_sem writers and i.e. affect workloads that perform frequent m(un)map or mprotect oterations. This patch simply releases the read lock before allocating a huge page. It also deletes an outdated comment that assumed vma must be stable, as it was using alloc_hugepage_vma(). This is no longer true since commit 9f1b868a ("mm: thp: khugepaged: add policy for finding target node"). Signed-off-by: NVlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Acked-by: NMel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: NDavid Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 03 10月, 2014 1 次提交
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由 Mel Gorman 提交于
This patch reverts 1ba6e0b5 ("mm: numa: split_huge_page: transfer the NUMA type from the pmd to the pte"). If a huge page is being split due a protection change and the tail will be in a PROT_NONE vma then NUMA hinting PTEs are temporarily created in the protected VMA. VM_RW|VM_PROTNONE |-----------------| ^ split here In the specific case above, it should get fixed up by change_pte_range() but there is a window of opportunity for weirdness to happen. Similarly, if a huge page is shrunk and split during a protection update but before pmd_numa is cleared then a pte_numa can be left behind. Instead of adding complexity trying to deal with the case, this patch will not mark PTEs NUMA when splitting a huge page. NUMA hinting faults will not be triggered which is marginal in comparison to the complexity in dealing with the corner cases during THP split. Cc: stable@vger.kernel.org Signed-off-by: NMel Gorman <mgorman@suse.de> Acked-by: NRik van Riel <riel@redhat.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 8月, 2014 1 次提交
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由 Johannes Weiner 提交于
These patches rework memcg charge lifetime to integrate more naturally with the lifetime of user pages. This drastically simplifies the code and reduces charging and uncharging overhead. The most expensive part of charging and uncharging is the page_cgroup bit spinlock, which is removed entirely after this series. Here are the top-10 profile entries of a stress test that reads a 128G sparse file on a freshly booted box, without even a dedicated cgroup (i.e. executing in the root memcg). Before: 15.36% cat [kernel.kallsyms] [k] copy_user_generic_string 13.31% cat [kernel.kallsyms] [k] memset 11.48% cat [kernel.kallsyms] [k] do_mpage_readpage 4.23% cat [kernel.kallsyms] [k] get_page_from_freelist 2.38% cat [kernel.kallsyms] [k] put_page 2.32% cat [kernel.kallsyms] [k] __mem_cgroup_commit_charge 2.18% kswapd0 [kernel.kallsyms] [k] __mem_cgroup_uncharge_common 1.92% kswapd0 [kernel.kallsyms] [k] shrink_page_list 1.86% cat [kernel.kallsyms] [k] __radix_tree_lookup 1.62% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn After: 15.67% cat [kernel.kallsyms] [k] copy_user_generic_string 13.48% cat [kernel.kallsyms] [k] memset 11.42% cat [kernel.kallsyms] [k] do_mpage_readpage 3.98% cat [kernel.kallsyms] [k] get_page_from_freelist 2.46% cat [kernel.kallsyms] [k] put_page 2.13% kswapd0 [kernel.kallsyms] [k] shrink_page_list 1.88% cat [kernel.kallsyms] [k] __radix_tree_lookup 1.67% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn 1.39% kswapd0 [kernel.kallsyms] [k] free_pcppages_bulk 1.30% cat [kernel.kallsyms] [k] kfree As you can see, the memcg footprint has shrunk quite a bit. text data bss dec hex filename 37970 9892 400 48262 bc86 mm/memcontrol.o.old 35239 9892 400 45531 b1db mm/memcontrol.o This patch (of 4): The memcg charge API charges pages before they are rmapped - i.e. have an actual "type" - and so every callsite needs its own set of charge and uncharge functions to know what type is being operated on. Worse, uncharge has to happen from a context that is still type-specific, rather than at the end of the page's lifetime with exclusive access, and so requires a lot of synchronization. Rewrite the charge API to provide a generic set of try_charge(), commit_charge() and cancel_charge() transaction operations, much like what's currently done for swap-in: mem_cgroup_try_charge() attempts to reserve a charge, reclaiming pages from the memcg if necessary. mem_cgroup_commit_charge() commits the page to the charge once it has a valid page->mapping and PageAnon() reliably tells the type. mem_cgroup_cancel_charge() aborts the transaction. This reduces the charge API and enables subsequent patches to drastically simplify uncharging. As pages need to be committed after rmap is established but before they are added to the LRU, page_add_new_anon_rmap() must stop doing LRU additions again. Revive lru_cache_add_active_or_unevictable(). [hughd@google.com: fix shmem_unuse] [hughd@google.com: Add comments on the private use of -EAGAIN] Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: NHugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 8月, 2014 4 次提交
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由 David Rientjes 提交于
Commit 9f1b868a ("mm: thp: khugepaged: add policy for finding target node") improved the previous khugepaged logic which allocated a transparent hugepages from the node of the first page being collapsed. However, it is still possible to collapse pages to remote memory which may suffer from additional access latency. With the current policy, it is possible that 255 pages (with PAGE_SHIFT == 12) will be collapsed remotely if the majority are allocated from that node. When zone_reclaim_mode is enabled, it means the VM should make every attempt to allocate locally to prevent NUMA performance degradation. In this case, we do not want to collapse hugepages to remote nodes that would suffer from increased access latency. Thus, when zone_reclaim_mode is enabled, only allow collapsing to nodes with RECLAIM_DISTANCE or less. There is no functional change for systems that disable zone_reclaim_mode. Signed-off-by: NDavid Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Acked-by: NMel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Bob Liu <bob.liu@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
Transparent huge page charges prefer falling back to regular pages rather than spending a lot of time in direct reclaim. Desired reclaim behavior is usually declared in the gfp mask, but THP charges use GFP_KERNEL and then rely on the fact that OOM is disabled for THP charges, and that OOM-disabled charges don't retry reclaim. Needless to say, this is anything but obvious and quite error prone. Convert THP charges to use GFP_TRANSHUGE instead, which implies __GFP_NORETRY, to indicate the low-latency requirement. Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Waiman Long 提交于
In some architectures like x86, atomic_add() is a full memory barrier. In that case, an additional smp_mb() is just a waste of time. This patch replaces that smp_mb() by smp_mb__after_atomic() which will avoid the redundant memory barrier in some architectures. With a 3.16-rc1 based kernel, this patch reduced the execution time of breaking 1000 transparent huge pages from 38,245us to 30,964us. A reduction of 19% which is quite sizeable. It also reduces the %cpu time of the __split_huge_page_refcount function in the perf profile from 2.18% to 1.15%. Signed-off-by: NWaiman Long <Waiman.Long@hp.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Scott J Norton <scott.norton@hp.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Waiman Long 提交于
In __split_huge_page_map(), the check for page_mapcount(page) is invariant within the for loop. Because of the fact that the macro is implemented using atomic_read(), the redundant check cannot be optimized away by the compiler leading to unnecessary read to the page structure. This patch moves the invariant bug check out of the loop so that it will be done only once. On a 3.16-rc1 based kernel, the execution time of a microbenchmark that broke up 1000 transparent huge pages using munmap() had an execution time of 38,245us and 38,548us with and without the patch respectively. The performance gain is about 1%. Signed-off-by: NWaiman Long <Waiman.Long@hp.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Scott J Norton <scott.norton@hp.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 6月, 2014 2 次提交
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由 Hugh Dickins 提交于
Trinity has reported: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: __lock_acquire (kernel/locking/lockdep.c:3070 (discriminator 1)) CPU: 6 PID: 16173 Comm: trinity-c364 Tainted: G W 3.15.0-rc1-next-20140415-sasha-00020-gaa90d09 #398 lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) _raw_spin_lock (include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:151) remove_migration_pte (mm/migrate.c:137) rmap_walk (mm/rmap.c:1628 mm/rmap.c:1699) remove_migration_ptes (mm/migrate.c:224) migrate_pages (mm/migrate.c:922 mm/migrate.c:960 mm/migrate.c:1126) migrate_misplaced_page (mm/migrate.c:1733) __handle_mm_fault (mm/memory.c:3762 mm/memory.c:3812 mm/memory.c:3925) handle_mm_fault (mm/memory.c:3948) __get_user_pages (mm/memory.c:1851) __mlock_vma_pages_range (mm/mlock.c:255) __mm_populate (mm/mlock.c:711) SyS_mlockall (include/linux/mm.h:1799 mm/mlock.c:817 mm/mlock.c:791) I believe this comes about because, whereas collapsing and splitting THP functions take anon_vma lock in write mode (which excludes concurrent rmap walks), faulting THP functions (write protection and misplaced NUMA) do not - and mostly they do not need to. But they do use a pmdp_clear_flush(), set_pmd_at() sequence which, for an instant (indeed, for a long instant, given the inter-CPU TLB flush in there), leaves *pmd neither present not trans_huge. Which can confuse a concurrent rmap walk, as when removing migration ptes, seen in the dumped trace. Although that rmap walk has a 4k page to insert, anon_vmas containing THPs are in no way segregated from 4k-page anon_vmas, so the 4k-intent mm_find_pmd() does need to cope with that instant when a trans_huge pmd is temporarily absent. I don't think we need strengthen the locking at the THP end: it's easily handled with an ACCESS_ONCE() before testing both conditions. And since mm_find_pmd() had only one caller who wanted a THP rather than a pmd, let's slightly repurpose it to fail when it hits a THP or non-present pmd, and open code split_huge_page_address() again. Signed-off-by: NHugh Dickins <hughd@google.com> Reported-by: NSasha Levin <sasha.levin@oracle.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Lameter <cl@gentwo.org> Cc: Dave Jones <davej@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hugh Dickins 提交于
Trinity has for over a year been reporting a CONFIG_DEBUG_PAGEALLOC oops in copy_page_rep() called from copy_user_huge_page() called from do_huge_pmd_wp_page(). I believe this is a DEBUG_PAGEALLOC false positive, due to the source page being split, and a tail page freed, while copy is in progress; and not a problem without DEBUG_PAGEALLOC, since the pmd_same() check will prevent a miscopy from being made visible. Fix by adding get_user_huge_page() and put_user_huge_page(): reducing to the usual get_page() and put_page() on head page in the usual config; but get and put references to all of the tail pages when DEBUG_PAGEALLOC. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NHugh Dickins <hughd@google.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: NSasha Levin <sasha.levin@oracle.com> Tested-by: NSasha Levin <sasha.levin@oracle.com> Cc: Dave Jones <davej@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 6月, 2014 2 次提交
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由 Andrew Morton 提交于
It was using a mix of pr_foo() and printk(KERN_ERR ...). Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill A. Shutemov 提交于
It doesn't make sense to have two assert checks for each invariant: one for printing and one for BUG(). Let's trigger BUG() if we print error message. Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 4月, 2014 1 次提交
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由 Kirill A. Shutemov 提交于
Sasha Levin has reported two THP BUGs[1][2]. I believe both of them have the same root cause. Let's look to them one by one. The first bug[1] is "kernel BUG at mm/huge_memory.c:1829!". It's BUG_ON(mapcount != page_mapcount(page)) in __split_huge_page(). From my testing I see that page_mapcount() is higher than mapcount here. I think it happens due to race between zap_huge_pmd() and page_check_address_pmd(). page_check_address_pmd() misses PMD which is under zap: CPU0 CPU1 zap_huge_pmd() pmdp_get_and_clear() __split_huge_page() anon_vma_interval_tree_foreach() __split_huge_page_splitting() page_check_address_pmd() mm_find_pmd() /* * We check if PMD present without taking ptl: no * serialization against zap_huge_pmd(). We miss this PMD, * it's not accounted to 'mapcount' in __split_huge_page(). */ pmd_present(pmd) == 0 BUG_ON(mapcount != page_mapcount(page)) // CRASH!!! page_remove_rmap(page) atomic_add_negative(-1, &page->_mapcount) The second bug[2] is "kernel BUG at mm/huge_memory.c:1371!". It's VM_BUG_ON_PAGE(!PageHead(page), page) in zap_huge_pmd(). This happens in similar way: CPU0 CPU1 zap_huge_pmd() pmdp_get_and_clear() page_remove_rmap(page) atomic_add_negative(-1, &page->_mapcount) __split_huge_page() anon_vma_interval_tree_foreach() __split_huge_page_splitting() page_check_address_pmd() mm_find_pmd() pmd_present(pmd) == 0 /* The same comment as above */ /* * No crash this time since we already decremented page->_mapcount in * zap_huge_pmd(). */ BUG_ON(mapcount != page_mapcount(page)) /* * We split the compound page here into small pages without * serialization against zap_huge_pmd() */ __split_huge_page_refcount() VM_BUG_ON_PAGE(!PageHead(page), page); // CRASH!!! So my understanding the problem is pmd_present() check in mm_find_pmd() without taking page table lock. The bug was introduced by me commit with commit 117b0791. Sorry for that. :( Let's open code mm_find_pmd() in page_check_address_pmd() and do the check under page table lock. Note that __page_check_address() does the same for PTE entires if sync != 0. I've stress tested split and zap code paths for 36+ hours by now and don't see crashes with the patch applied. Before it took <20 min to trigger the first bug and few hours for second one (if we ignore first). [1] https://lkml.kernel.org/g/<53440991.9090001@oracle.com> [2] https://lkml.kernel.org/g/<5310C56C.60709@oracle.com> Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: NSasha Levin <sasha.levin@oracle.com> Tested-by: NSasha Levin <sasha.levin@oracle.com> Cc: Bob Liu <lliubbo@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michel Lespinasse <walken@google.com> Cc: Dave Jones <davej@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [3.13+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 4月, 2014 1 次提交
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由 Dongsheng Yang 提交于
Replace various -20/+19 hardcoded nice values with MIN_NICE/MAX_NICE. Signed-off-by: NDongsheng Yang <yangds.fnst@cn.fujitsu.com> Acked-by: NTejun Heo <tj@kernel.org> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/ff13819fd09b7a5dba5ab5ae797f2e7019bdfa17.1394532288.git.yangds.fnst@cn.fujitsu.com Cc: devel@driverdev.osuosl.org Cc: devicetree@vger.kernel.org Cc: fcoe-devel@open-fcoe.org Cc: linux390@de.ibm.com Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-s390@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: nbd-general@lists.sourceforge.net Cc: ocfs2-devel@oss.oracle.com Cc: openipmi-developer@lists.sourceforge.net Cc: qla2xxx-upstream@qlogic.com Cc: linux-arch@vger.kernel.org [ Consolidated the patches, twiddled the changelog. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 08 4月, 2014 1 次提交
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由 Michal Hocko 提交于
mem_cgroup_newpage_charge is used only for charging anonymous memory so it is better to rename it to mem_cgroup_charge_anon. mem_cgroup_cache_charge is used for file backed memory so rename it to mem_cgroup_charge_file. Signed-off-by: NMichal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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