- 11 Apr, 2018 36 commits
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Tom Abraham authored
Calling swapon() on a zero length swap file on SSD can lead to a divide-by-zero. Although creating such files isn't possible with mkswap and they woud be considered invalid, it would be better for the swapon code to be more robust and handle this condition gracefully (return -EINVAL). Especially since the fix is small and straightforward. To help with wear leveling on SSD, the swapon syscall calculates a random position in the swap file using modulo p->highest_bit, which is set to maxpages - 1 in read_swap_header. If the swap file is zero length, read_swap_header sets maxpages=1 and last_page=0, resulting in p->highest_bit=0 and we divide-by-zero when we modulo p->highest_bit in swapon syscall. This can be prevented by having read_swap_header return zero if last_page is zero. Link: http://lkml.kernel.org/r/5AC747C1020000A7001FA82C@prv-mh.provo.novell.comSigned-off-by:
Thomas Abraham <tabraham@suse.com> Reported-by: <Mark.Landis@Teradata.com> Reviewed-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored
Commit a983b5eb ("mm: memcontrol: fix excessive complexity in memory.stat reporting") added per-cpu drift to all memory cgroup stats and events shown in memory.stat and memory.events. For memory.stat this is acceptable. But memory.events issues file notifications, and somebody polling the file for changes will be confused when the counters in it are unchanged after a wakeup. Luckily, the events in memory.events - MEMCG_LOW, MEMCG_HIGH, MEMCG_MAX, MEMCG_OOM - are sufficiently rare and high-level that we don't need per-cpu buffering for them: MEMCG_HIGH and MEMCG_MAX would be the most frequent, but they're counting invocations of reclaim, which is a complex operation that touches many shared cachelines. This splits memory.events from the generic VM events and tracks them in their own, unbuffered atomic counters. That's also cleaner, as it eliminates the ugly enum nesting of VM and cgroup events. [hannes@cmpxchg.org: "array subscript is above array bounds"] Link: http://lkml.kernel.org/r/20180406155441.GA20806@cmpxchg.org Link: http://lkml.kernel.org/r/20180405175507.GA24817@cmpxchg.org Fixes: a983b5eb ("mm: memcontrol: fix excessive complexity in memory.stat reporting") Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Reported-by:
Tejun Heo <tj@kernel.org> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Roman Gushchin <guro@fb.com> Cc: Rik van Riel <riel@surriel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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Claudio Imbrenda authored
When using KSM with use_zero_pages, we replace anonymous pages containing only zeroes with actual zero pages, which are not anonymous. We need to do proper accounting of the mm counters, otherwise we will get wrong values in /proc and a BUG message in dmesg when tearing down the mm. Link: http://lkml.kernel.org/r/1522931274-15552-1-git-send-email-imbrenda@linux.vnet.ibm.com Fixes: e86c59b1 ("mm/ksm: improve deduplication of zero pages with colouring") Signed-off-by:
Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Reviewed-by:
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Matthew Wilcox authored
We have a perfectly good macro to determine whether the gfp flags allow you to sleep or not; use it instead of trying to infer it. Link: http://lkml.kernel.org/r/20180408062206.GC16007@bombadil.infradead.orgSigned-off-by:
Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by:
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Xidong Wang authored
In z3fold_create_pool(), the memory allocated by __alloc_percpu() is not released on the error path that pool->compact_wq , which holds the return value of create_singlethread_workqueue(), is NULL. This will result in a memory leak bug. [akpm@linux-foundation.org: fix oops on kzalloc() failure, check __alloc_percpu() retval] Link: http://lkml.kernel.org/r/1522803111-29209-1-git-send-email-wangxidong_97@163.comSigned-off-by:
Xidong Wang <wangxidong_97@163.com> Reviewed-by:
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Michal Hocko authored
A THP memcg charge can trigger the oom killer since 25160354 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations"). We have used an explicit __GFP_NORETRY previously which ruled the OOM killer automagically. Memcg charge path should be semantically compliant with the allocation path and that means that if we do not trigger the OOM killer for costly orders which should do the same in the memcg charge path as well. Otherwise we are forcing callers to distinguish the two and use different gfp masks which is both non-intuitive and bug prone. As soon as we get a costly high order kmalloc user we even do not have any means to tell the memcg specific gfp mask to prevent from OOM because the charging is deep within guts of the slab allocator. The unexpected memcg OOM on THP has already been fixed upstream by 9d3c3354 ("mm, thp: do not cause memcg oom for thp") but this is a one-off fix rather than a generic solution. Teach mem_cgroup_oom to bail out on costly order requests to fix the THP issue as well as any other costly OOM eligible allocations to be added in future. Also revert 9d3c3354 because special gfp for THP is no longer needed. Link: http://lkml.kernel.org/r/20180403193129.22146-1-mhocko@kernel.org Fixes: 25160354 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations") Signed-off-by:
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Ralph Campbell authored
Use of pte_write(pte) is only valid for present pte, the common code which set the migration entry can be reach for both valid present pte and special swap entry (for device memory). Fix the code to use the mpfn value which properly handle both cases. On x86 this did not have any bad side effect because pte write bit is below PAGE_BIT_GLOBAL and thus special swap entry have it set to 0 which in turn means we were always creating read only special migration entry. So once migration did finish we always write protected the CPU page table entry (moreover this is only an issue when migrating from device memory to system memory). End effect is that CPU write access would fault again and restore write permission. This behaviour isn't too bad; it just burns CPU cycles by forcing CPU to take a second fault on write access. ie, double faulting the same address. There is no corruption or incorrect states (it behaves as a COWed page from a fork with a mapcount of 1). Link: http://lkml.kernel.org/r/20180402023506.12180-1-jglisse@redhat.comSigned-off-by:
Ralph Campbell <rcampbell@nvidia.com> Signed-off-by:
Jérôme Glisse <jglisse@redhat.com> Signed-off-by:
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Wei Yang authored
__highest_present_section_nr is a more strict boundary than NR_MEM_SECTIONS. So checking __highest_present_section_nr directly is enough. Link: http://lkml.kernel.org/r/20180330032044.21647-1-richard.weiyang@gmail.comSigned-off-by:
Wei Yang <richard.weiyang@gmail.com> Reviewed-by:
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Mel Gorman authored
change_pte_range is called from task work context to mark PTEs for receiving NUMA faulting hints. If the marked pages are dirty then migration may fail. Some filesystems cannot migrate dirty pages without blocking so are skipped in MIGRATE_ASYNC mode which just wastes CPU. Even when they can, it can be a waste of cycles when the pages are shared forcing higher scan rates. This patch avoids marking shared dirty pages for hinting faults but also will skip a migration if the page was dirtied after the scanner updated a clean page. This is most noticeable running the NASA Parallel Benchmark when backed by btrfs, the default root filesystem for some distributions, but also noticeable when using XFS. The following are results from a 4-socket machine running a 4.16-rc4 kernel with some scheduler patches that are pending for the next merge window. 4.16.0-rc4 4.16.0-rc4 schedtip-20180309 nodirty-v1 Time cg.D 459.07 ( 0.00%) 444.21 ( 3.24%) Time ep.D 76.96 ( 0.00%) 77.69 ( -0.95%) Time is.D 25.55 ( 0.00%) 27.85 ( -9.00%) Time lu.D 601.58 ( 0.00%) 596.87 ( 0.78%) Time mg.D 107.73 ( 0.00%) 108.22 ( -0.45%) is.D regresses slightly in terms of absolute time but note that that particular load varies quite a bit from run to run. The more relevant observation is the total system CPU usage. 4.16.0-rc4 4.16.0-rc4 schedtip-20180309 nodirty-v1 User 71471.91 70627.04 System 11078.96 8256.13 Elapsed 661.66 632.74 That is a substantial drop in system CPU usage and overall the workload completes faster. The NUMA balancing statistics are also interesting NUMA base PTE updates 111407972 139848884 NUMA huge PMD updates 206506 264869 NUMA page range updates 217139044 275461812 NUMA hint faults 4300924 3719784 NUMA hint local faults 3012539 3416618 NUMA hint local percent 70 91 NUMA pages migrated 1517487 1358420 While more PTEs are scanned due to changes in what faults are gathered, it's clear that a far higher percentage of faults are local as the bulk of the remote hits were dirty pages that, in this case with btrfs, had no chance of migrating. The following is a comparison when using XFS as that is a more realistic filesystem choice for a data partition 4.16.0-rc4 4.16.0-rc4 schedtip-20180309 nodirty-v1r47 Time cg.D 485.28 ( 0.00%) 442.62 ( 8.79%) Time ep.D 77.68 ( 0.00%) 77.54 ( 0.18%) Time is.D 26.44 ( 0.00%) 24.79 ( 6.24%) Time lu.D 597.46 ( 0.00%) 597.11 ( 0.06%) Time mg.D 142.65 ( 0.00%) 105.83 ( 25.81%) That is a reasonable gain on two relatively long-lived workloads. While not presented, there is also a substantial drop in system CPu usage and the NUMA balancing stats show similar improvements in locality as btrfs did. Link: http://lkml.kernel.org/r/20180326094334.zserdec62gwmmfqf@techsingularity.netSigned-off-by:Mel Gorman <mgorman@techsingularity.net> Reviewed-by:
Rik van Riel <riel@surriel.com> Signed-off-by:
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Jérôme Glisse authored
This fix typos and syntaxes, thanks to Randy Dunlap for pointing them out (they were all my faults). Link: http://lkml.kernel.org/r/20180409151859.4713-1-jglisse@redhat.comSigned-off-by:
Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
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Arnd Bergmann authored
The last fix was still wrong, as we need the inline dummy functions also for the case that CONFIG_HMM is enabled but CONFIG_HMM_MIRROR is not: kernel/fork.o: In function `__mmdrop': fork.c:(.text+0x14f6): undefined reference to `hmm_mm_destroy' This adds back the second copy of the dummy functions, hopefully this time in the right place. Link: http://lkml.kernel.org/r/20180404110236.804484-1-arnd@arndb.de Fixes: 8900d06a277a ("mm/hmm: fix header file if/else/endif maze") Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Reviewed-by:
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Tejun Heo authored
hmm_devmem_find() requires rcu_read_lock_held() but there's nothing which actually uses the RCU protection. The only caller is hmm_devmem_pages_create() which already grabs the mutex and does superfluous rcu_read_lock/unlock() around the function. This doesn't add anything and just adds to confusion. Remove the RCU protection and open-code the radix tree lookup. If this needs to become more sophisticated in the future, let's add them back when necessary. Link: http://lkml.kernel.org/r/20180314194515.1661824-4-tj@kernel.orgSigned-off-by:
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Jérôme Glisse authored
Users of hmm_vma_fault() and hmm_vma_get_pfns() provide a flags array and pfn shift value allowing them to define their own encoding for HMM pfn that are fill inside the pfns array of the hmm_range struct. With this device driver can get pfn that match their own private encoding out of HMM without having to do any conversion. [rcampbell@nvidia.com: don't ignore specific pte fault flag in hmm_vma_fault()] Link: http://lkml.kernel.org/r/20180326213009.2460-2-jglisse@redhat.com [rcampbell@nvidia.com: clarify fault logic for device private memory] Link: http://lkml.kernel.org/r/20180326213009.2460-3-jglisse@redhat.com Link: http://lkml.kernel.org/r/20180323005527.758-16-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
This changes hmm_vma_fault() to not take a global write fault flag for a range but instead rely on caller to populate HMM pfns array with proper fault flag ie HMM_PFN_VALID if driver want read fault for that address or HMM_PFN_VALID and HMM_PFN_WRITE for write. Moreover by setting HMM_PFN_DEVICE_PRIVATE the device driver can ask for device private memory to be migrated back to system memory through page fault. This is more flexible API and it better reflects how device handles and reports fault. Link: http://lkml.kernel.org/r/20180323005527.758-15-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
No functional change, just create one function to handle pmd and one to handle pte (hmm_vma_handle_pmd() and hmm_vma_handle_pte()). Link: http://lkml.kernel.org/r/20180323005527.758-14-jglisse@redhat.comSigned-off-by:
John Hubbard <jhubbard@nvidia.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Mark Hairgrove <mhairgrove@nvidia.com> Signed-off-by:
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Jérôme Glisse authored
Move hmm_pfns_clear() closer to where it is used to make it clear it is not use by page table walkers. Link: http://lkml.kernel.org/r/20180323005527.758-13-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
Make naming consistent across code, DEVICE_PRIVATE is the name use outside HMM code so use that one. Link: http://lkml.kernel.org/r/20180323005527.758-12-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
There is no point in differentiating between a range for which there is not even a directory (and thus entries) and empty entry (pte_none() or pmd_none() returns true). Simply drop the distinction ie remove HMM_PFN_EMPTY flag and merge now duplicate hmm_vma_walk_hole() and hmm_vma_walk_clear() functions. Link: http://lkml.kernel.org/r/20180323005527.758-11-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
Special vma (one with any of the VM_SPECIAL flags) can not be access by device because there is no consistent model across device drivers on those vma and their backing memory. This patch directly use hmm_range struct for hmm_pfns_special() argument as it is always affecting the whole vma and thus the whole range. It also make behavior consistent after this patch both hmm_vma_fault() and hmm_vma_get_pfns() returns -EINVAL when facing such vma. Previously hmm_vma_fault() returned 0 and hmm_vma_get_pfns() return -EINVAL but both were filling the HMM pfn array with special entry. Link: http://lkml.kernel.org/r/20180323005527.758-10-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
All device driver we care about are using 64bits page table entry. In order to match this and to avoid useless define convert all HMM pfn to directly use uint64_t. It is a first step on the road to allow driver to directly use pfn value return by HMM (saving memory and CPU cycles use for conversion between the two). Link: http://lkml.kernel.org/r/20180323005527.758-9-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
Only peculiar architecture allow write without read thus assume that any valid pfn do allow for read. Note we do not care for write only because it does make sense with thing like atomic compare and exchange or any other operations that allow you to get the memory value through them. Link: http://lkml.kernel.org/r/20180323005527.758-8-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
Both hmm_vma_fault() and hmm_vma_get_pfns() were taking a hmm_range struct as parameter and were initializing that struct with others of their parameters. Have caller of those function do this as they are likely to already do and only pass this struct to both function this shorten function signature and make it easier in the future to add new parameters by simply adding them to the structure. Link: http://lkml.kernel.org/r/20180323005527.758-7-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
The private field of mm_walk struct point to an hmm_vma_walk struct and not to the hmm_range struct desired. Fix to get proper struct pointer. Link: http://lkml.kernel.org/r/20180323005527.758-6-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
This code was lost in translation at one point. This properly call mmu_notifier_unregister_no_release() once last user is gone. This fix the zombie mm_struct as without this patch we do not drop the refcount we have on it. Link: http://lkml.kernel.org/r/20180323005527.758-5-jglisse@redhat.comSigned-off-by:
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Ralph Campbell authored
hmm_mirror_register() registers a callback for when the CPU pagetable is modified. Normally, the device driver will call hmm_mirror_unregister() when the process using the device is finished. However, if the process exits uncleanly, the struct_mm can be destroyed with no warning to the device driver. Link: http://lkml.kernel.org/r/20180323005527.758-4-jglisse@redhat.comSigned-off-by:
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Jérôme Glisse authored
The #if/#else/#endif for IS_ENABLED(CONFIG_HMM) were wrong. Because of this after multiple include there was multiple definition of both hmm_mm_init() and hmm_mm_destroy() leading to build failure if HMM was enabled (CONFIG_HMM set). Link: http://lkml.kernel.org/r/20180323005527.758-3-jglisse@redhat.comSigned-off-by:
Balbir Singh <bsingharora@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Ralph Campbell authored
Update the documentation for HMM to fix minor typos and phrasing to be a bit more readable. Link: http://lkml.kernel.org/r/20180323005527.758-2-jglisse@redhat.comSigned-off-by:
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Steven Rostedt authored
The trace event trace_mm_vmscan_lru_shrink_inactive() currently has 12 parameters! Seven of them are from the reclaim_stat structure. This structure is currently local to mm/vmscan.c. By moving it to the global vmstat.h header, we can also reference it from the vmscan tracepoints. In moving it, it brings down the overhead of passing so many arguments to the trace event. In the future, we may limit the number of arguments that a trace event may pass (ideally just 6, but more realistically it may be 8). Before this patch, the code to call the trace event is this: 0f 83 aa fe ff ff jae ffffffff811e6261 <shrink_inactive_list+0x1e1> 48 8b 45 a0 mov -0x60(%rbp),%rax 45 8b 64 24 20 mov 0x20(%r12),%r12d 44 8b 6d d4 mov -0x2c(%rbp),%r13d 8b 4d d0 mov -0x30(%rbp),%ecx 44 8b 75 cc mov -0x34(%rbp),%r14d 44 8b 7d c8 mov -0x38(%rbp),%r15d 48 89 45 90 mov %rax,-0x70(%rbp) 8b 83 b8 fe ff ff mov -0x148(%rbx),%eax 8b 55 c0 mov -0x40(%rbp),%edx 8b 7d c4 mov -0x3c(%rbp),%edi 8b 75 b8 mov -0x48(%rbp),%esi 89 45 80 mov %eax,-0x80(%rbp) 65 ff 05 e4 f7 e2 7e incl %gs:0x7ee2f7e4(%rip) # 15bd0 <__preempt_count> 48 8b 05 75 5b 13 01 mov 0x1135b75(%rip),%rax # ffffffff8231bf68 <__tracepoint_mm_vmscan_lru_shrink_inactive+0x28> 48 85 c0 test %rax,%rax 74 72 je ffffffff811e646a <shrink_inactive_list+0x3ea> 48 89 c3 mov %rax,%rbx 4c 8b 10 mov (%rax),%r10 89 f8 mov %edi,%eax 48 89 85 68 ff ff ff mov %rax,-0x98(%rbp) 89 f0 mov %esi,%eax 48 89 85 60 ff ff ff mov %rax,-0xa0(%rbp) 89 c8 mov %ecx,%eax 48 89 85 78 ff ff ff mov %rax,-0x88(%rbp) 89 d0 mov %edx,%eax 48 89 85 70 ff ff ff mov %rax,-0x90(%rbp) 8b 45 8c mov -0x74(%rbp),%eax 48 8b 7b 08 mov 0x8(%rbx),%rdi 48 83 c3 18 add $0x18,%rbx 50 push %rax 41 54 push %r12 41 55 push %r13 ff b5 78 ff ff ff pushq -0x88(%rbp) 41 56 push %r14 41 57 push %r15 ff b5 70 ff ff ff pushq -0x90(%rbp) 4c 8b 8d 68 ff ff ff mov -0x98(%rbp),%r9 4c 8b 85 60 ff ff ff mov -0xa0(%rbp),%r8 48 8b 4d 98 mov -0x68(%rbp),%rcx 48 8b 55 90 mov -0x70(%rbp),%rdx 8b 75 80 mov -0x80(%rbp),%esi 41 ff d2 callq *%r10 After the patch: 0f 83 a8 fe ff ff jae ffffffff811e626d <shrink_inactive_list+0x1cd> 8b 9b b8 fe ff ff mov -0x148(%rbx),%ebx 45 8b 64 24 20 mov 0x20(%r12),%r12d 4c 8b 6d a0 mov -0x60(%rbp),%r13 65 ff 05 f5 f7 e2 7e incl %gs:0x7ee2f7f5(%rip) # 15bd0 <__preempt_count> 4c 8b 35 86 5b 13 01 mov 0x1135b86(%rip),%r14 # ffffffff8231bf68 <__tracepoint_mm_vmscan_lru_shrink_inactive+0x28> 4d 85 f6 test %r14,%r14 74 2a je ffffffff811e6411 <shrink_inactive_list+0x371> 49 8b 06 mov (%r14),%rax 8b 4d 8c mov -0x74(%rbp),%ecx 49 8b 7e 08 mov 0x8(%r14),%rdi 49 83 c6 18 add $0x18,%r14 4c 89 ea mov %r13,%rdx 45 89 e1 mov %r12d,%r9d 4c 8d 45 b8 lea -0x48(%rbp),%r8 89 de mov %ebx,%esi 51 push %rcx 48 8b 4d 98 mov -0x68(%rbp),%rcx ff d0 callq *%rax Link: http://lkml.kernel.org/r/2559d7cb-ec60-1200-2362-04fa34fd02bb@fb.com Link: http://lkml.kernel.org/r/20180322121003.4177af15@gandalf.local.homeSigned-off-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Reported-by:
Alexei Starovoitov <ast@fb.com> Acked-by:
David Rientjes <rientjes@google.com> Acked-by:
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Andrey Ryabinin authored
memcg reclaim may alter pgdat->flags based on the state of LRU lists in cgroup and its children. PGDAT_WRITEBACK may force kswapd to sleep congested_wait(), PGDAT_DIRTY may force kswapd to writeback filesystem pages. But the worst here is PGDAT_CONGESTED, since it may force all direct reclaims to stall in wait_iff_congested(). Note that only kswapd have powers to clear any of these bits. This might just never happen if cgroup limits configured that way. So all direct reclaims will stall as long as we have some congested bdi in the system. Leave all pgdat->flags manipulations to kswapd. kswapd scans the whole pgdat, only kswapd can clear pgdat->flags once node is balanced, thus it's reasonable to leave all decisions about node state to kswapd. Why only kswapd? Why not allow to global direct reclaim change these flags? It is because currently only kswapd can clear these flags. I'm less worried about the case when PGDAT_CONGESTED falsely not set, and more worried about the case when it falsely set. If direct reclaimer sets PGDAT_CONGESTED, do we have guarantee that after the congestion problem is sorted out, kswapd will be woken up and clear the flag? It seems like there is no such guarantee. E.g. direct reclaimers may eventually balance pgdat and kswapd simply won't wake up (see wakeup_kswapd()). Moving pgdat->flags manipulation to kswapd, means that cgroup2 recalim now loses its congestion throttling mechanism. Add per-cgroup congestion state and throttle cgroup2 reclaimers if memcg is in congestion state. Currently there is no need in per-cgroup PGDAT_WRITEBACK and PGDAT_DIRTY bits since they alter only kswapd behavior. The problem could be easily demonstrated by creating heavy congestion in one cgroup: echo "+memory" > /sys/fs/cgroup/cgroup.subtree_control mkdir -p /sys/fs/cgroup/congester echo 512M > /sys/fs/cgroup/congester/memory.max echo $$ > /sys/fs/cgroup/congester/cgroup.procs /* generate a lot of diry data on slow HDD */ while true; do dd if=/dev/zero of=/mnt/sdb/zeroes bs=1M count=1024; done & .... while true; do dd if=/dev/zero of=/mnt/sdb/zeroes bs=1M count=1024; done & and some job in another cgroup: mkdir /sys/fs/cgroup/victim echo 128M > /sys/fs/cgroup/victim/memory.max # time cat /dev/sda > /dev/null real 10m15.054s user 0m0.487s sys 1m8.505s According to the tracepoint in wait_iff_congested(), the 'cat' spent 50% of the time sleeping there. With the patch, cat don't waste time anymore: # time cat /dev/sda > /dev/null real 5m32.911s user 0m0.411s sys 0m56.664s [aryabinin@virtuozzo.com: congestion state should be per-node] Link: http://lkml.kernel.org/r/20180406135215.10057-1-aryabinin@virtuozzo.com [ayabinin@virtuozzo.com: make congestion state per-cgroup-per-node instead of just per-cgroup[ Link: http://lkml.kernel.org/r/20180406180254.8970-2-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20180323152029.11084-5-aryabinin@virtuozzo.comSigned-off-by:Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by:
Shakeel Butt <shakeelb@google.com> Acked-by:
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Andrey Ryabinin authored
We have separate LRU list for each memory cgroup. Memory reclaim iterates over cgroups and calls shrink_inactive_list() every inactive LRU list. Based on the state of a single LRU shrink_inactive_list() may flag the whole node as dirty,congested or under writeback. This is obviously wrong and hurtful. It's especially hurtful when we have possibly small congested cgroup in system. Than *all* direct reclaims waste time by sleeping in wait_iff_congested(). And the more memcgs in the system we have the longer memory allocation stall is, because wait_iff_congested() called on each lru-list scan. Sum reclaim stats across all visited LRUs on node and flag node as dirty, congested or under writeback based on that sum. Also call congestion_wait(), wait_iff_congested() once per pgdat scan, instead of once per lru-list scan. This only fixes the problem for global reclaim case. Per-cgroup reclaim may alter global pgdat flags too, which is wrong. But that is separate issue and will be addressed in the next patch. This change will not have any effect on a systems with all workload concentrated in a single cgroup. [aryabinin@virtuozzo.com: check nr_writeback against all nr_taken, not just file] Link: http://lkml.kernel.org/r/20180406180254.8970-1-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20180323152029.11084-4-aryabinin@virtuozzo.comSigned-off-by:
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Andrey Ryabinin authored
Only kswapd can have non-zero nr_immediate, and current_may_throttle() is always true for kswapd (PF_LESS_THROTTLE bit is never set) thus it's enough to check stat.nr_immediate only. Link: http://lkml.kernel.org/r/20180315164553.17856-4-aryabinin@virtuozzo.comSigned-off-by:
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Andrey Ryabinin authored
Update some comments that became stale since transiton from per-zone to per-node reclaim. Link: http://lkml.kernel.org/r/20180315164553.17856-2-aryabinin@virtuozzo.comSigned-off-by:
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Roman Gushchin authored
Indirectly reclaimable memory can consume a significant part of total memory and it's actually reclaimable (it will be released under actual memory pressure). So, the overcommit logic should treat it as free. Otherwise, it's possible to cause random system-wide memory allocation failures by consuming a significant amount of memory by indirectly reclaimable memory, e.g. dentry external names. If overcommit policy GUESS is used, it might be used for denial of service attack under some conditions. The following program illustrates the approach. It causes the kernel to allocate an unreclaimable kmalloc-256 chunk for each stat() call, so that at some point the overcommit logic may start blocking large allocation system-wide. int main() { char buf[256]; unsigned long i; struct stat statbuf; buf[0] = '/'; for (i = 1; i < sizeof(buf); i++) buf[i] = '_'; for (i = 0; 1; i++) { sprintf(&buf[248], "%8lu", i); stat(buf, &statbuf); } return 0; } This patch in combination with related indirectly reclaimable memory patches closes this issue. Link: http://lkml.kernel.org/r/20180313130041.8078-1-guro@fb.comSigned-off-by:Roman Gushchin <guro@fb.com> Reviewed-by:
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Roman Gushchin authored
I received a report about suspicious growth of unreclaimable slabs on some machines. I've found that it happens on machines with low memory pressure, and these unreclaimable slabs are external names attached to dentries. External names are allocated using generic kmalloc() function, so they are accounted as unreclaimable. But they are held by dentries, which are reclaimable, and they will be reclaimed under the memory pressure. In particular, this breaks MemAvailable calculation, as it doesn't take unreclaimable slabs into account. This leads to a silly situation, when a machine is almost idle, has no memory pressure and therefore has a big dentry cache. And the resulting MemAvailable is too low to start a new workload. To address the issue, the NR_INDIRECTLY_RECLAIMABLE_BYTES counter is used to track the amount of memory, consumed by external names. The counter is increased in the dentry allocation path, if an external name structure is allocated; and it's decreased in the dentry freeing path. To reproduce the problem I've used the following Python script: import os for iter in range (0, 10000000): try: name = ("/some_long_name_%d" % iter) + "_" * 220 os.stat(name) except Exception: pass Without this patch: $ cat /proc/meminfo | grep MemAvailable MemAvailable: 7811688 kB $ python indirect.py $ cat /proc/meminfo | grep MemAvailable MemAvailable: 2753052 kB With the patch: $ cat /proc/meminfo | grep MemAvailable MemAvailable: 7809516 kB $ python indirect.py $ cat /proc/meminfo | grep MemAvailable MemAvailable: 7749144 kB [guro@fb.com: fix indirectly reclaimable memory accounting for CONFIG_SLOB] Link: http://lkml.kernel.org/r/20180312194140.19517-1-guro@fb.com [guro@fb.com: fix indirectly reclaimable memory accounting] Link: http://lkml.kernel.org/r/20180313125701.7955-1-guro@fb.com Link: http://lkml.kernel.org/r/20180305133743.12746-5-guro@fb.comSigned-off-by: -
Roman Gushchin authored
Adjust /proc/meminfo MemAvailable calculation by adding the amount of indirectly reclaimable memory (rounded to the PAGE_SIZE). Link: http://lkml.kernel.org/r/20180305133743.12746-4-guro@fb.comSigned-off-by:
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Roman Gushchin authored
Patch series "indirectly reclaimable memory", v2. This patchset introduces the concept of indirectly reclaimable memory and applies it to fix the issue of when a big number of dentries with external names can significantly affect the MemAvailable value. This patch (of 3): Introduce a concept of indirectly reclaimable memory and adds the corresponding memory counter and /proc/vmstat item. Indirectly reclaimable memory is any sort of memory, used by the kernel (except of reclaimable slabs), which is actually reclaimable, i.e. will be released under memory pressure. The counter is in bytes, as it's not always possible to count such objects in pages. The name contains BYTES by analogy to NR_KERNEL_STACK_KB. Link: http://lkml.kernel.org/r/20180305133743.12746-2-guro@fb.comSigned-off-by:
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- 10 Apr, 2018 4 commits
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git://linux-c6x.org/git/projects/linux-c6x-upstreamingLinus Torvalds authored
Pull c6x updates from Mark Salter. * tag 'for-linus' of git://linux-c6x.org/git/projects/linux-c6x-upstreaming: c6x: pass endianness info to sparse c6x: fix platforms/plldata.c get_coreid build error c6x: remove unused KTHREAD_SIZE definition
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git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/mipsLinus Torvalds authored
Pull MIPS updates from James Hogan: "These are the main MIPS changes for 4.17. Rough overview: (1) generic platform: Add support for Microsemi Ocelot SoCs (2) crypto: Add CRC32 and CRC32C HW acceleration module (3) Various cleanups and misc improvements More detailed summary: Miscellaneous: - hang more efficiently on halt/powerdown/restart - pm-cps: Block system suspend when a JTAG probe is present - expand make help text for generic defconfigs - refactor handling of legacy defconfigs - determine the entry point from the ELF file header to fix microMIPS for certain toolchains - introduce isa-rev.h for MIPS_ISA_REV and use to simplify other code Minor cleanups: - DTS: boston/ci20: Unit name cleanups and correction - kdump: Make the default for PHYSICAL_START always 64-bit - constify gpio_led in Alchemy, AR7, and TXX9 - silence a couple of W=1 warnings - remove duplicate includes Platform support: Generic platform: - add support for Microsemi Ocelot - dt-bindings: Add vendor prefix for Microsemi Corporation - dt-bindings: Add bindings for Microsemi SoCs - add ocelot SoC & PCB123 board DTS files - MAINTAINERS: Add entry for Microsemi MIPS SoCs - enable crc32-mips on r6 configs ath79: - fix AR724X_PLL_REG_PCIE_CONFIG offset BCM47xx: - firmware: Use mac_pton() for MAC address parsing - add Luxul XAP1500/XWR1750 WiFi LEDs - use standard reset button for Luxul XWR-1750 BMIPS: - enable CONFIG_BRCMSTB_PM in bmips_stb_defconfig for build coverage - add STB PM, wake-up timer, watchdog DT nodes Octeon: - drop '.' after newlines in printk calls ralink: - pci-mt7621: Enable PCIe on MT7688" * tag 'mips_4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/mips: (37 commits) MIPS: BCM47XX: Use standard reset button for Luxul XWR-1750 MIPS: BCM47XX: Add Luxul XAP1500/XWR1750 WiFi LEDs MIPS: Make the default for PHYSICAL_START always 64-bit MIPS: Use the entry point from the ELF file header MAINTAINERS: Add entry for Microsemi MIPS SoCs MIPS: generic: Add support for Microsemi Ocelot MIPS: mscc: Add ocelot PCB123 device tree MIPS: mscc: Add ocelot dtsi dt-bindings: mips: Add bindings for Microsemi SoCs dt-bindings: Add vendor prefix for Microsemi Corporation MIPS: ath79: Fix AR724X_PLL_REG_PCIE_CONFIG offset MIPS: pci-mt7620: Enable PCIe on MT7688 MIPS: pm-cps: Block system suspend when a JTAG probe is present MIPS: VDSO: Replace __mips_isa_rev with MIPS_ISA_REV MIPS: BPF: Replace __mips_isa_rev with MIPS_ISA_REV MIPS: cpu-features.h: Replace __mips_isa_rev with MIPS_ISA_REV MIPS: Introduce isa-rev.h to define MIPS_ISA_REV MIPS: Hang more efficiently on halt/powerdown/restart FIRMWARE: bcm47xx_nvram: Replace mac address parsing MIPS: BMIPS: Add Broadcom STB watchdog nodes ... -
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-traceLinus Torvalds authored
Pull tracing updates from Steven Rostedt: "New features: - Tom Zanussi's extended histogram work. This adds the synthetic events to have histograms from multiple event data Adds triggers "onmatch" and "onmax" to call the synthetic events Several updates to the histogram code from this - Allow way to nest ring buffer calls in the same context - Allow absolute time stamps in ring buffer - Rewrite of filter code parsing based on Al Viro's suggestions - Setting of trace_clock to global if TSC is unstable (on boot) - Better OOM handling when allocating large ring buffers - Added initcall tracepoints (consolidated initcall_debug code with them) And other various fixes and clean ups" * tag 'trace-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (68 commits) init: Have initcall_debug still work without CONFIG_TRACEPOINTS init, tracing: Have printk come through the trace events for initcall_debug init, tracing: instrument security and console initcall trace events init, tracing: Add initcall trace events tracing: Add rcu dereference annotation for test func that touches filter->prog tracing: Add rcu dereference annotation for filter->prog tracing: Fixup logic inversion on setting trace_global_clock defaults tracing: Hide global trace clock from lockdep ring-buffer: Add set/clear_current_oom_origin() during allocations ring-buffer: Check if memory is available before allocation lockdep: Add print_irqtrace_events() to __warn vsprintf: Do not preprocess non-dereferenced pointers for bprintf (%px and %pK) tracing: Uninitialized variable in create_tracing_map_fields() tracing: Make sure variable string fields are NULL-terminated tracing: Add action comparisons when testing matching hist triggers tracing: Don't add flag strings when displaying variable references tracing: Fix display of hist trigger expressions containing timestamps ftrace: Drop a VLA in module_exists() tracing: Mention trace_clock=global when warning about unstable clocks tracing: Default to using trace_global_clock if sched_clock is unstable ... -
git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimmLinus Torvalds authored
Pull libnvdimm updates from Dan Williams: "This cycle was was not something I ever want to repeat as there were several late changes that have only now just settled. Half of the branch up to commit d2c997c0 ("fs, dax: use page->mapping to warn...") have been in -next for several releases. The of_pmem driver and the address range scrub rework were late arrivals, and the dax work was scaled back at the last moment. The of_pmem driver missed a previous merge window due to an oversight. A sense of obligation to rectify that miss is why it is included for 4.17. It has acks from PowerPC folks. Stephen reported a build failure that only occurs when merging it with your latest tree, for now I have fixed that up by disabling modular builds of of_pmem. A test merge with your tree has received a build success report from the 0day robot over 156 configs. An initial version of the ARS rework was submitted before the merge window. It is self contained to libnvdimm, a net code reduction, and passing all unit tests. The filesystem-dax changes are based on the wait_var_event() functionality from tip/sched/core. However, late review feedback showed that those changes regressed truncate performance to a large degree. The branch was rewound to drop the truncate behavior change and now only includes preparation patches and cleanups (with full acks and reviews). The finalization of this dax-dma-vs-trnucate work will need to wait for 4.18. Summary: - A rework of the filesytem-dax implementation provides for detection of unmap operations (truncate / hole punch) colliding with in-progress device-DMA. A fix for these collisions remains a work-in-progress pending resolution of truncate latency and starvation regressions. - The of_pmem driver expands the users of libnvdimm outside of x86 and ACPI to describe an implementation of persistent memory on PowerPC with Open Firmware / Device tree. - Address Range Scrub (ARS) handling is completely rewritten to account for the fact that ARS may run for 100s of seconds and there is no platform defined way to cancel it. ARS will now no longer block namespace initialization. - The NVDIMM Namespace Label implementation is updated to handle label areas as small as 1K, down from 128K. - Miscellaneous cleanups and updates to unit test infrastructure" * tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (39 commits) libnvdimm, of_pmem: workaround OF_NUMA=n build error nfit, address-range-scrub: add module option to skip initial ars nfit, address-range-scrub: rework and simplify ARS state machine nfit, address-range-scrub: determine one platform max_ars value powerpc/powernv: Create platform devs for nvdimm buses doc/devicetree: Persistent memory region bindings libnvdimm: Add device-tree based driver libnvdimm: Add of_node to region and bus descriptors libnvdimm, region: quiet region probe libnvdimm, namespace: use a safe lookup for dimm device name libnvdimm, dimm: fix dpa reservation vs uninitialized label area libnvdimm, testing: update the default smart ctrl_temperature libnvdimm, testing: Add emulation for smart injection commands nfit, address-range-scrub: introduce nfit_spa->ars_state libnvdimm: add an api to cast a 'struct nd_region' to its 'struct device' nfit, address-range-scrub: fix scrub in-progress reporting dax, dm: allow device-mapper to operate without dax support dax: introduce CONFIG_DAX_DRIVER fs, dax: use page->mapping to warn if truncate collides with a busy page ext2, dax: introduce ext2_dax_aops ...
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