- 26 Oct, 2018 40 commits
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Keith Busch authored
If the '-w' parameter was provided, the benchmark would exit due to a mssing 'break'. Link: http://lkml.kernel.org/r/20181010195605.10689-3-keith.busch@intel.comSigned-off-by:
Keith Busch <keith.busch@intel.com> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by:
Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Keith Busch authored
Provide new gup benchmark ioctl commands to run different user page pinning methods, get_user_pages_longterm() and get_user_pages(), in addition to the existing get_user_pages_fast(). Link: http://lkml.kernel.org/r/20181010195605.10689-2-keith.busch@intel.comSigned-off-by:
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Keith Busch authored
We'd like to measure time to unpin user pages, so this adds a second benchmark timer on put_page, separate from get_page. Adding the field breaks this ioctl ABI, but should be okay since this an in-tree kernel selftest. [akpm@linux-foundation.org: add expansion to struct gup_benchmark for future use] Link: http://lkml.kernel.org/r/20181010195605.10689-1-keith.busch@intel.comSigned-off-by:
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Roman Gushchin authored
It was reported that on some of our machines containers were restarted with OOM symptoms without an obvious reason. Despite there were almost no memory pressure and plenty of page cache, MEMCG_OOM event was raised occasionally, causing the container management software to think, that OOM has happened. However, no tasks have been killed. The following investigation showed that the problem is caused by a failing attempt to charge a high-order page. In such case, the OOM killer is never invoked. As shown below, it can happen under conditions, which are very far from a real OOM: e.g. there is plenty of clean page cache and no memory pressure. There is no sense in raising an OOM event in this case, as it might confuse a user and lead to wrong and excessive actions (e.g. restart the workload, as in my case). Let's look at the charging path in try_charge(). If the memory usage is about memory.max, which is absolutely natural for most memory cgroups, we try to reclaim some pages. Even if we were able to reclaim enough memory for the allocation, the following check can fail due to a race with another concurrent allocation: if (mem_cgroup_margin(mem_over_limit) >= nr_pages) goto retry; For regular pages the following condition will save us from triggering the OOM: if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) goto retry; But for high-order allocation this condition will intentionally fail. The reason behind is that we'll likely fall to regular pages anyway, so it's ok and even preferred to return ENOMEM. In this case the idea of raising MEMCG_OOM looks dubious. Fix this by moving MEMCG_OOM raising to mem_cgroup_oom() after allocation order check, so that the event won't be raised for high order allocations. This change doesn't affect regular pages allocation and charging. Link: http://lkml.kernel.org/r/20181004214050.7417-1-guro@fb.comSigned-off-by:Roman Gushchin <guro@fb.com> Acked-by:
David Rientjes <rientjes@google.com> Acked-by:
Michal Hocko <mhocko@kernel.org> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by:
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Dave Chinner authored
We've recently seen a workload on XFS filesystems with a repeatable deadlock between background writeback and a multi-process application doing concurrent writes and fsyncs to a small range of a file. range_cyclic writeback Process 1 Process 2 xfs_vm_writepages write_cache_pages writeback_index = 2 cycled = 0 .... find page 2 dirty lock Page 2 ->writepage page 2 writeback page 2 clean page 2 added to bio no more pages write() locks page 1 dirties page 1 locks page 2 dirties page 1 fsync() .... xfs_vm_writepages write_cache_pages start index 0 find page 1 towrite lock Page 1 ->writepage page 1 writeback page 1 clean page 1 added to bio find page 2 towrite lock Page 2 page 2 is writeback <blocks> write() locks page 1 dirties page 1 fsync() .... xfs_vm_writepages write_cache_pages start index 0 !done && !cycled sets index to 0, restarts lookup find page 1 dirty find page 1 towrite lock Page 1 page 1 is writeback <blocks> lock Page 1 <blocks> DEADLOCK because: - process 1 needs page 2 writeback to complete to make enough progress to issue IO pending for page 1 - writeback needs page 1 writeback to complete so process 2 can progress and unlock the page it is blocked on, then it can issue the IO pending for page 2 - process 2 can't make progress until process 1 issues IO for page 1 The underlying cause of the problem here is that range_cyclic writeback is processing pages in descending index order as we hold higher index pages in a structure controlled from above write_cache_pages(). The write_cache_pages() caller needs to be able to submit these pages for IO before write_cache_pages restarts writeback at mapping index 0 to avoid wcp inverting the page lock/writeback wait order. generic_writepages() is not susceptible to this bug as it has no private context held across write_cache_pages() - filesystems using this infrastructure always submit pages in ->writepage immediately and so there is no problem with range_cyclic going back to mapping index 0. However: mpage_writepages() has a private bio context, exofs_writepages() has page_collect fuse_writepages() has fuse_fill_wb_data nfs_writepages() has nfs_pageio_descriptor xfs_vm_writepages() has xfs_writepage_ctx All of these ->writepages implementations can hold pages under writeback in their private structures until write_cache_pages() returns, and hence they are all susceptible to this deadlock. Also worth noting is that ext4 has it's own bastardised version of write_cache_pages() and so it /may/ have an equivalent deadlock. I looked at the code long enough to understand that it has a similar retry loop for range_cyclic writeback reaching the end of the file and then promptly ran away before my eyes bled too much. I'll leave it for the ext4 developers to determine if their code is actually has this deadlock and how to fix it if it has. There's a few ways I can see avoid this deadlock. There's probably more, but these are the first I've though of: 1. get rid of range_cyclic altogether 2. range_cyclic always stops at EOF, and we start again from writeback index 0 on the next call into write_cache_pages() 2a. wcp also returns EAGAIN to ->writepages implementations to indicate range cyclic has hit EOF. writepages implementations can then flush the current context and call wpc again to continue. i.e. lift the retry into the ->writepages implementation 3. range_cyclic uses trylock_page() rather than lock_page(), and it skips pages it can't lock without blocking. It will already do this for pages under writeback, so this seems like a no-brainer 3a. all non-WB_SYNC_ALL writeback uses trylock_page() to avoid blocking as per pages under writeback. I don't think #1 is an option - range_cyclic prevents frequently dirtied lower file offset from starving background writeback of rarely touched higher file offsets. #2 is simple, and I don't think it will have any impact on performance as going back to the start of the file implies an immediate seek. We'll have exactly the same number of seeks if we switch writeback to another inode, and then come back to this one later and restart from index 0. #2a is pretty much "status quo without the deadlock". Moving the retry loop up into the wcp caller means we can issue IO on the pending pages before calling wcp again, and so avoid locking or waiting on pages in the wrong order. I'm not convinced we need to do this given that we get the same thing from #2 on the next writeback call from the writeback infrastructure. #3 is really just a band-aid - it doesn't fix the access/wait inversion problem, just prevents it from becoming a deadlock situation. I'd prefer we fix the inversion, not sweep it under the carpet like this. #3a is really an optimisation that just so happens to include the band-aid fix of #3. So it seems that the simplest way to fix this issue is to implement solution #2 Link: http://lkml.kernel.org/r/20181005054526.21507-1-david@fromorbit.comSigned-off-by:Dave Chinner <dchinner@redhat.com> Reviewed-by:
Jan Kara <jack@suse.de> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by:
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Pavel Tatashin authored
memmap_init_zone, is getting complex, because it is called from different contexts: hotplug, and during boot, and also because it must handle some architecture quirks. One of them is mirrored memory. Move the code that decides whether to skip mirrored memory outside of memmap_init_zone, into a separate function. [pasha.tatashin@oracle.com: uninline overlap_memmap_init()] Link: http://lkml.kernel.org/r/20180726193509.3326-4-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180724235520.10200-4-pasha.tatashin@oracle.comSigned-off-by:
Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by:
Oscar Salvador <osalvador@suse.de> Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by:
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Pavel Tatashin authored
update_defer_init() should be called only when struct page is about to be initialized. Because it counts number of initialized struct pages, but there we may skip struct pages if there is some mirrored memory. So move, update_defer_init() after checking for mirrored memory. Also, rename update_defer_init() to defer_init() and reverse the return boolean to emphasize that this is a boolean function, that tells that the reset of memmap initialization should be deferred. Make this function self-contained: do not pass number of already initialized pages in this zone by using static counters. I found this bug by reading the code. The effect is that fewer than expected struct pages are initialized early in boot, and it is possible that in some corner cases we may fail to boot when mirrored pages are used. The deferred on demand code should somewhat mitigate this. But this still brings some inconsistencies compared to when booting without mirrored pages, so it is better to fix. [pasha.tatashin@oracle.com: add comment about defer_init's lack of locking] Link: http://lkml.kernel.org/r/20180726193509.3326-3-pasha.tatashin@oracle.com [akpm@linux-foundation.org: make defer_init non-inline, __meminit] Link: http://lkml.kernel.org/r/20180724235520.10200-3-pasha.tatashin@oracle.comSigned-off-by:
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Pavel Tatashin authored
memmap_init is sometimes a macro sometimes a function based on __HAVE_ARCH_MEMMAP_INIT. It is only a function on ia64. Make memmap_init a weak function instead, and let ia64 redefine it. Link: http://lkml.kernel.org/r/20180724235520.10200-2-pasha.tatashin@oracle.comSigned-off-by:
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Kirill Tkhai authored
This will allow to use generic refcount_t interfaces to check counters overflow instead of currently existing VM_BUG_ON(). The only difference after the patch is VM_BUG_ON() may cause BUG(), while refcount_t fires with WARN(). But this seems not to be significant here, since such the problems are usually caught by syzbot with panic-on-warn enabled. Link: http://lkml.kernel.org/r/153910718919.7006.13400779039257185427.stgit@localhost.localdomainSigned-off-by:
Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by:
Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Andrea Parri <andrea.parri@amarulasolutions.com> Signed-off-by:
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David Rientjes authored
If move_freepages_block() returns 0 because !zone_spans_pfn(), *num_movable can hold the value from the stack because it does not get initialized in move_freepages(). Move the initialization to move_freepages_block() to guarantee the value actually makes sense. This currently doesn't affect its only caller where num_movable != NULL, so no bug fix, but just more robust. Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1810051355490.212229@chino.kir.corp.google.comSigned-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Greg Thelen <gthelen@google.com> Signed-off-by:
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Gustavo A. R. Silva authored
Replace "fallthru" with a proper "fall through" annotation. This fix is part of the ongoing efforts to enabling -Wimplicit-fallthrough Link: http://lkml.kernel.org/r/20181003105114.GA24423@embeddedor.comSigned-off-by:
Gustavo A. R. Silva <gustavo@embeddedor.com> Reviewed-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by:
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Peter Xu authored
Now we recycle the uffd servicing threads earlier than the lock threads. It might happen that when the lock thread is still blocked at a pthread mutex lock while the servicing thread has already quitted for the cpu so the lock thread will be blocked forever and hang the test program. To fix the possible race, recycle the lock threads first. This never happens with current missing-only tests, but when I start to run the write-protection tests (the feature is not yet posted upstream) it happens every time of the run possibly because in that new test we'll need to service two page faults for each lock operation. Link: http://lkml.kernel.org/r/20180930074259.18229-4-peterx@redhat.comSigned-off-by:
Peter Xu <peterx@redhat.com> Acked-by:
Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Shaohua Li <shli@fb.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com> Signed-off-by:
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Peter Xu authored
We do very similar things in read and poll modes, but we're copying the codes around. Share the codes properly on reading the message and handling the page fault to make the code cleaner. Meanwhile this solves previous mismatch of behaviors between the two modes on that the old code: - did not check EAGAIN case in read() mode - ignored BOUNCE_VERIFY check in read() mode Link: http://lkml.kernel.org/r/20180930074259.18229-3-peterx@redhat.comSigned-off-by:
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Peter Xu authored
Firstly, the help in the comment region is obsolete, now we support three parameters. Since at it, change it and move it into the help message of the program. Also, the help messages dumped here and there is obsolete too. Use a single usage() helper. Link: http://lkml.kernel.org/r/20180930074259.18229-2-peterx@redhat.comSigned-off-by:
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Jann Horn authored
Having two gigantic arrays that must manually be kept in sync, including ifdefs, isn't exactly robust. To make it easier to catch such issues in the future, add a BUILD_BUG_ON(). Link: http://lkml.kernel.org/r/20181001143138.95119-3-jannh@google.comSigned-off-by:
Jann Horn <jannh@google.com> Reviewed-by:
Kees Cook <keescook@chromium.org> Reviewed-by:
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Aneesh Kumar K.V authored
We clear the pte temporarily during read/modify/write update of the pte. If we take a page fault while the pte is cleared, the application can get SIGBUS. One such case is with remap_pfn_range without a backing vm_ops->fault callback. do_fault will return SIGBUS in that case. cpu 0 cpu1 mprotect() ptep_modify_prot_start()/pte cleared. . . page fault. . . prep_modify_prot_commit() Fix this by taking page table lock and rechecking for pte_none. [aneesh.kumar@linux.ibm.com: fix crash observed with syzkaller run] Link: http://lkml.kernel.org/r/87va6bwlfg.fsf@linux.ibm.com Link: http://lkml.kernel.org/r/20180926031858.9692-1-aneesh.kumar@linux.ibm.comSigned-off-by:
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by:
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Yang Shi authored
The comment for PFN_SPECIAL is missed in pfn_t.h. Add comment to get consistent with other pfn flags. Link: http://lkml.kernel.org/r/1538086549-100536-1-git-send-email-yang.shi@linux.alibaba.comSigned-off-by:
Yang Shi <yang.shi@linux.alibaba.com> Suggested-by:
Dan Williams <dan.j.williams@intel.com> Reviewed-by:
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Yang Shi authored
brk might be used to shrink memory mapping too other than munmap(). So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The brk() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case. But, it may set mm->brk after __do_munmap(), which needs hold write mmap_sem. However, a simple trick can workaround this by setting mm->brk before __do_munmap(). Then restore the original value if __do_munmap() fails. With this trick, it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-2-git-send-email-yang.shi@linux.alibaba.comSigned-off-by: -
Yang Shi authored
Other than munmap, mremap might be used to shrink memory mapping too. So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The mremap() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case, so it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. MREMAP_FIXED and MREMAP_MAYMOVE are more complicated to adopt this optimization since they need manipulate vmas after do_munmap(), downgrading mmap_sem may create race window. Simple mapping shrink is the low hanging fruit, and it may cover the most cases of unmap with munmap together. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-2-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-1-git-send-email-yang.shi@linux.alibaba.comSigned-off-by: -
Souptick Joarder authored
These codes can be replaced with new inline vmf_error(). Link: http://lkml.kernel.org/r/20180927171411.GA23331@jordon-HP-15-Notebook-PCSigned-off-by:
Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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Alexandre Ghiti authored
ia64, mips, parisc, powerpc, sh, sparc, x86 architectures use the same version of huge_ptep_get, so move this generic implementation into asm-generic/hugetlb.h. [arnd@arndb.de: fix ARM 3level page tables] Link: http://lkml.kernel.org/r/20181005161722.904274-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20180920060358.16606-12-alex@ghiti.frSigned-off-by:
Alexandre Ghiti <alex@ghiti.fr> Reviewed-by:
Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by:
Mike Kravetz <mike.kravetz@oracle.com> Tested-by: Helge Deller <deller@gmx.de> [parisc] Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Acked-by: Paul Burton <paul.burton@mips.com> [MIPS] Acked-by: Ingo Molnar <mingo@kernel.org> [x86] Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David S. Miller <davem@davemloft.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James E.J. Bottomley <jejb@parisc-linux.org> Cc: James Hogan <jhogan@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by:
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Alexandre Ghiti authored
arm, ia64, sh, x86 architectures use the same version of huge_ptep_set_access_flags, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-11-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, ia64, mips, powerpc, sh, x86 architectures use the same version of huge_ptep_set_wrprotect, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-10-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, arm64, powerpc, sparc, x86 architectures use the same version of prepare_hugepage_range, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-9-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, arm64, ia64, mips, parisc, powerpc, sh, sparc, x86 architectures use the same version of huge_pte_wrprotect, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-8-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, arm64, ia64, mips, parisc, powerpc, sh, sparc, x86 architectures use the same version of huge_pte_none, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-7-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, x86 architectures use the same version of huge_ptep_clear_flush, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-6-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, ia64, sh, x86 architectures use the same version of huge_ptep_get_and_clear, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-5-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, ia64, mips, powerpc, sh, x86 architectures use the same version of set_huge_pte_at, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-4-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
arm, arm64, mips, parisc, sh, x86 architectures use the same version of hugetlb_free_pgd_range, so move this generic implementation into asm-generic/hugetlb.h. Link: http://lkml.kernel.org/r/20180920060358.16606-3-alex@ghiti.frSigned-off-by:
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Alexandre Ghiti authored
In order to reduce copy/paste of functions across architectures and then make riscv hugetlb port (and future ports) simpler and smaller, this patchset intends to factorize the numerous hugetlb primitives that are defined across all the architectures. Except for prepare_hugepage_range, this patchset moves the versions that are just pass-through to standard pte primitives into asm-generic/hugetlb.h by using the same #ifdef semantic that can be found in asm-generic/pgtable.h, i.e. __HAVE_ARCH_***. s390 architecture has not been tackled in this serie since it does not use asm-generic/hugetlb.h at all. This patchset has been compiled on all addressed architectures with success (except for parisc, but the problem does not come from this series). This patch (of 11): asm-generic/hugetlb.h proposes generic implementations of hugetlb related functions: use __HAVE_ARCH_HUGE* defines in order to make arch specific implementations of hugetlb functions consistent with pgtable.h scheme. Link: http://lkml.kernel.org/r/20180920060358.16606-2-alex@ghiti.frSigned-off-by:
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Wei Yang authored
The local variable `addr' in __get_user_pages_fast() is just a shadow of `start'. Since `start' never changes after assignment to `addr', it is fine to replace `start' with it. Also the meaning of [start, end] is more obvious than [addr, end] when passed to gup_pgd_range(). Link: http://lkml.kernel.org/r/20180925021448.20265-1-richard.weiyang@gmail.comSigned-off-by:
Wei Yang <richard.weiyang@gmail.com> Reviewed-by:
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Alexander Duyck authored
The ZONE_DEVICE pages were being initialized in two locations. One was with the memory_hotplug lock held and another was outside of that lock. The problem with this is that it was nearly doubling the memory initialization time. Instead of doing this twice, once while holding a global lock and once without, I am opting to defer the initialization to the one outside of the lock. This allows us to avoid serializing the overhead for memory init and we can instead focus on per-node init times. One issue I encountered is that devm_memremap_pages and hmm_devmmem_pages_create were initializing only the pgmap field the same way. One wasn't initializing hmm_data, and the other was initializing it to a poison value. Since this is something that is exposed to the driver in the case of hmm I am opting for a third option and just initializing hmm_data to 0 since this is going to be exposed to unknown third party drivers. [alexander.h.duyck@linux.intel.com: fix reference count for pgmap in devm_memremap_pages] Link: http://lkml.kernel.org/r/20181008233404.1909.37302.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/20180925202053.3576.66039.stgit@localhost.localdomainSigned-off-by:
Alexander Duyck <alexander.h.duyck@linux.intel.com> Reviewed-by:
Pavel Tatashin <pavel.tatashin@microsoft.com> Tested-by:
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Alexander Duyck authored
It doesn't make much sense to use the atomic SetPageReserved at init time when we are using memset to clear the memory and manipulating the page flags via simple "&=" and "|=" operations in __init_single_page. This patch adds a non-atomic version __SetPageReserved that can be used during page init and shows about a 10% improvement in initialization times on the systems I have available for testing. On those systems I saw initialization times drop from around 35 seconds to around 32 seconds to initialize a 3TB block of persistent memory. I believe the main advantage of this is that it allows for more compiler optimization as the __set_bit operation can be reordered whereas the atomic version cannot. I tried adding a bit of documentation based on f1dd2cd1 ("mm, memory_hotplug: do not associate hotadded memory to zones until online"). Ideally the reserved flag should be set earlier since there is a brief window where the page is initialization via __init_single_page and we have not set the PG_Reserved flag. I'm leaving that for a future patch set as that will require a more significant refactor. Link: http://lkml.kernel.org/r/20180925202018.3576.11607.stgit@localhost.localdomainSigned-off-by:
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Alexander Duyck authored
Patch series "Address issues slowing persistent memory initialization", v5. The main thing this patch set achieves is that it allows us to initialize each node worth of persistent memory independently. As a result we reduce page init time by about 2 minutes because instead of taking 30 to 40 seconds per node and going through each node one at a time, we process all 4 nodes in parallel in the case of a 12TB persistent memory setup spread evenly over 4 nodes. This patch (of 3): On systems with a large amount of memory it can take a significant amount of time to initialize all of the page structs with the PAGE_POISON_PATTERN value. I have seen it take over 2 minutes to initialize a system with over 12TB of RAM. In order to work around the issue I had to disable CONFIG_DEBUG_VM and then the boot time returned to something much more reasonable as the arch_add_memory call completed in milliseconds versus seconds. However in doing that I had to disable all of the other VM debugging on the system. In order to work around a kernel that might have CONFIG_DEBUG_VM enabled on a system that has a large amount of memory I have added a new kernel parameter named "vm_debug" that can be set to "-" in order to disable it. Link: http://lkml.kernel.org/r/20180925201921.3576.84239.stgit@localhost.localdomainReviewed-by:
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Shakeel Butt authored
The flag memcg_kmem_skip_account was added during the era of opt-out kmem accounting. There is no need for such flag in the opt-in world as there aren't any __GFP_ACCOUNT allocations within memcg_create_cache_enqueue(). Link: http://lkml.kernel.org/r/20180919004501.178023-1-shakeelb@google.comSigned-off-by:
Shakeel Butt <shakeelb@google.com> Acked-by:
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Oscar Salvador authored
This patch, as the previous one, gets rid of the wrong if statements. While at it, I realized that the comments are sometimes very confusing, to say the least, and wrong. For example: ___ zone_last = ZONE_MOVABLE; /* * check whether node_states[N_HIGH_MEMORY] will be changed * If we try to offline the last present @nr_pages from the node, * we can determind we will need to clear the node from * node_states[N_HIGH_MEMORY]. */ for (; zt <= zone_last; zt++) present_pages += pgdat->node_zones[zt].present_pages; if (nr_pages >= present_pages) arg->status_change_nid = zone_to_nid(zone); else arg->status_change_nid = -1; ___ In case the node gets empry, it must be removed from N_MEMORY. We already check N_HIGH_MEMORY a bit above within the CONFIG_HIGHMEM ifdef code. Not to say that status_change_nid is for N_MEMORY, and not for N_HIGH_MEMORY. So I re-wrote some of the comments to what I think is better. [osalvador@suse.de: address feedback from Pavel] Link: http://lkml.kernel.org/r/20180921132634.10103-5-osalvador@techadventures.net Link: http://lkml.kernel.org/r/20180919100819.25518-6-osalvador@techadventures.netSigned-off-by: -
Oscar Salvador authored
While looking at node_states_check_changes_online, I stumbled upon some confusing things. Right after entering the function, we find this: if (N_MEMORY == N_NORMAL_MEMORY) zone_last = ZONE_MOVABLE; This is wrong. N_MEMORY cannot really be equal to N_NORMAL_MEMORY. My guess is that this wanted to be something like: if (N_NORMAL_MEMORY == N_HIGH_MEMORY) to check if we have CONFIG_HIGHMEM. Later on, in the CONFIG_HIGHMEM block, we have: if (N_MEMORY == N_HIGH_MEMORY) zone_last = ZONE_MOVABLE; Again, this is wrong, and will never be evaluated to true. Besides removing these wrong if statements, I simplified the function a bit. [osalvador@suse.de: address feedback from Pavel] Link: http://lkml.kernel.org/r/20180921132634.10103-4-osalvador@techadventures.net Link: http://lkml.kernel.org/r/20180919100819.25518-5-osalvador@techadventures.netSigned-off-by: -
Oscar Salvador authored
node_states_clear has the following if statements: if ((N_MEMORY != N_NORMAL_MEMORY) && (arg->status_change_nid_high >= 0)) ... if ((N_MEMORY != N_HIGH_MEMORY) && (arg->status_change_nid >= 0)) ... N_MEMORY can never be equal to neither N_NORMAL_MEMORY nor N_HIGH_MEMORY. Similar problem was found in [1]. Since this is wrong, let us get rid of it. [1] https://patchwork.kernel.org/patch/10579155/ Link: http://lkml.kernel.org/r/20180919100819.25518-4-osalvador@techadventures.netSigned-off-by: -
Oscar Salvador authored
In node_states_check_changes_online, we check if the node will have to be set for any of the N_*_MEMORY states after the pages have been onlined. Later on, we perform the activation in node_states_set_node. Currently, in node_states_set_node we set the node to N_MEMORY unconditionally. This means that we call node_set_state for N_MEMORY every time pages go online, but we only need to do it if the node has not yet been set for N_MEMORY. Fix this by checking status_change_nid. Link: http://lkml.kernel.org/r/20180919100819.25518-2-osalvador@techadventures.netSigned-off-by:
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