mirror of https://github.com/torvalds/linux.git
618 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Vladimir Davydov
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5ccc5abaaf |
mm: free swap cache aggressively if memcg swap is full
Swap cache pages are freed aggressively if swap is nearly full (>50% currently), because otherwise we are likely to stop scanning anonymous when we near the swap limit even if there is plenty of freeable swap cache pages. We should follow the same trend in case of memory cgroup, which has its own swap limit. Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dan Williams
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5c7fb56e5e |
mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd
A dax-huge-page mapping while it uses some thp helpers is ultimately not a transparent huge page. The distinction is especially important in the get_user_pages() path. pmd_devmap() is used to distinguish dax-pmds from pmd_huge() and pmd_trans_huge() which have slightly different semantics. Explicitly mark the pmd_trans_huge() helpers that dax needs by adding pmd_devmap() checks. [kirill.shutemov@linux.intel.com: fix regression in handling mlocked pages in __split_huge_pmd()] Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave@sr71.net> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dan Williams
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f25748e3c3 |
mm, dax: convert vmf_insert_pfn_pmd() to pfn_t
Similar to the conversion of vm_insert_mixed() use pfn_t in the vmf_insert_pfn_pmd() to tag the resulting pte with _PAGE_DEVICE when the pfn is backed by a devm_memremap_pages() mapping. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave@sr71.net> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dan Williams
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01c8f1c44b |
mm, dax, gpu: convert vm_insert_mixed to pfn_t
Convert the raw unsigned long 'pfn' argument to pfn_t for the purpose of evaluating the PFN_MAP and PFN_DEV flags. When both are set it triggers _PAGE_DEVMAP to be set in the resulting pte. There are no functional changes to the gpu drivers as a result of this conversion. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave@sr71.net> Cc: David Airlie <airlied@linux.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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e90309c9f7 |
thp: allow mlocked THP again
Before THP refcounting rework, THP was not allowed to cross VMA
boundary. So, if we have THP and we split it, PG_mlocked can be safely
transferred to small pages.
With new THP refcounting and naive approach to mlocking we can end up
with this scenario:
1. we have a mlocked THP, which belong to one VM_LOCKED VMA.
2. the process does munlock() on the *part* of the THP:
- the VMA is split into two, one of them VM_LOCKED;
- huge PMD split into PTE table;
- THP is still mlocked;
3. split_huge_page():
- it transfers PG_mlocked to *all* small pages regrardless if it
blong to any VM_LOCKED VMA.
We probably could munlock() all small pages on split_huge_page(), but I
think we have accounting issue already on step two.
Instead of forbidding mlocked pages altogether, we just avoid mlocking
PTE-mapped THPs and munlock THPs on split_huge_pmd().
This means PTE-mapped THPs will be on normal lru lists and will be split
under memory pressure by vmscan. After the split vmscan will detect
unevictable small pages and mlock them.
With this approach we shouldn't hit situation like described above.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Kirill A. Shutemov
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e81c48024f |
mm, numa: skip PTE-mapped THP on numa fault
We're going to have THP mapped with PTEs. It will confuse numabalancing. Let's skip them for now. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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53f9263bab |
mm: rework mapcount accounting to enable 4k mapping of THPs
We're going to allow mapping of individual 4k pages of THP compound. It means we need to track mapcount on per small page basis. Straight-forward approach is to use ->_mapcount in all subpages to track how many time this subpage is mapped with PMDs or PTEs combined. But this is rather expensive: mapping or unmapping of a THP page with PMD would require HPAGE_PMD_NR atomic operations instead of single we have now. The idea is to store separately how many times the page was mapped as whole -- compound_mapcount. This frees up ->_mapcount in subpages to track PTE mapcount. We use the same approach as with compound page destructor and compound order to store compound_mapcount: use space in first tail page, ->mapping this time. Any time we map/unmap whole compound page (THP or hugetlb) -- we increment/decrement compound_mapcount. When we map part of compound page with PTE we operate on ->_mapcount of the subpage. page_mapcount() counts both: PTE and PMD mappings of the page. Basically, we have mapcount for a subpage spread over two counters. It makes tricky to detect when last mapcount for a page goes away. We introduced PageDoubleMap() for this. When we split THP PMD for the first time and there's other PMD mapping left we offset up ->_mapcount in all subpages by one and set PG_double_map on the compound page. These additional references go away with last compound_mapcount. This approach provides a way to detect when last mapcount goes away on per small page basis without introducing new overhead for most common cases. [akpm@linux-foundation.org: fix typo in comment] [mhocko@suse.com: ignore partial THP when moving task] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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4b471e8898 |
mm, thp: remove infrastructure for handling splitting PMDs
With new refcounting we don't need to mark PMDs splitting. Let's drop code to handle this. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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78ddc53473 |
thp: rename split_huge_page_pmd() to split_huge_pmd()
We are going to decouple splitting THP PMD from splitting underlying compound page. This patch renames split_huge_page_pmd*() functions to split_huge_pmd*() to reflect the fact that it doesn't imply page splitting, only PMD. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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7479df6da9 |
thp, mlock: do not allow huge pages in mlocked area
With new refcounting THP can belong to several VMAs. This makes tricky to track THP pages, when they partially mlocked. It can lead to leaking mlocked pages to non-VM_LOCKED vmas and other problems. With this patch we will split all pages on mlock and avoid fault-in/collapse new THP in VM_LOCKED vmas. I've tried alternative approach: do not mark THP pages mlocked and keep them on normal LRUs. This way vmscan could try to split huge pages on memory pressure and free up subpages which doesn't belong to VM_LOCKED vmas. But this is user-visible change: we screw up Mlocked accouting reported in meminfo, so I had to leave this approach aside. We can bring something better later, but this should be good enough for now. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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f627c2f537 |
memcg: adjust to support new THP refcounting
As with rmap, with new refcounting we cannot rely on PageTransHuge() to check if we need to charge size of huge page form the cgroup. We need to get information from caller to know whether it was mapped with PMD or PTE. We do uncharge when last reference on the page gone. At that point if we see PageTransHuge() it means we need to unchange whole huge page. The tricky part is partial unmap -- when we try to unmap part of huge page. We don't do a special handing of this situation, meaning we don't uncharge the part of huge page unless last user is gone or split_huge_page() is triggered. In case of cgroup memory pressure happens the partial unmapped page will be split through shrinker. This should be good enough. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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d281ee6145 |
rmap: add argument to charge compound page
We're going to allow mapping of individual 4k pages of THP compound page. It means we cannot rely on PageTransHuge() check to decide if map/unmap small page or THP. The patch adds new argument to rmap functions to indicate whether we want to operate on whole compound page or only the small page. [n-horiguchi@ah.jp.nec.com: fix mapcount mismatch in hugepage migration] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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1c290f6421 |
mm: sanitize page->mapping for tail pages
We don't define meaning of page->mapping for tail pages. Currently it's always NULL, which can be inconsistent with head page and potentially lead to problems. Let's poison the pointer to catch all illigal uses. page_rmapping(), page_mapping() and page_anon_vma() are changed to look on head page. The only illegal use I've caught so far is __GPF_COMP pages from sound subsystem, mapped with PTEs. do_shared_fault() is changed to use page_rmapping() instead of direct access to fault_page->mapping. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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c20cd45eb0 |
mm: allow GFP_{FS,IO} for page_cache_read page cache allocation
page_cache_read has been historically using page_cache_alloc_cold to allocate a new page. This means that mapping_gfp_mask is used as the base for the gfp_mask. Many filesystems are setting this mask to GFP_NOFS to prevent from fs recursion issues. page_cache_read is called from the vm_operations_struct::fault() context during the page fault. This context doesn't need the reclaim protection normally. ceph and ocfs2 which call filemap_fault from their fault handlers seem to be OK because they are not taking any fs lock before invoking generic implementation. xfs which takes XFS_MMAPLOCK_SHARED is safe from the reclaim recursion POV because this lock serializes truncate and punch hole with the page faults and it doesn't get involved in the reclaim. There is simply no reason to deliberately use a weaker allocation context when a __GFP_FS | __GFP_IO can be used. The GFP_NOFS protection might be even harmful. There is a push to fail GFP_NOFS allocations rather than loop within allocator indefinitely with a very limited reclaim ability. Once we start failing those requests the OOM killer might be triggered prematurely because the page cache allocation failure is propagated up the page fault path and end up in pagefault_out_of_memory. We cannot play with mapping_gfp_mask directly because that would be racy wrt. parallel page faults and it might interfere with other users who really rely on NOFS semantic from the stored gfp_mask. The mask is also inode proper so it would even be a layering violation. What we can do instead is to push the gfp_mask into struct vm_fault and allow fs layer to overwrite it should the callback need to be called with a different allocation context. Initialize the default to (mapping_gfp_mask | __GFP_FS | __GFP_IO) because this should be safe from the page fault path normally. Why do we care about mapping_gfp_mask at all then? Because this doesn't hold only reclaim protection flags but it also might contain zone and movability restrictions (GFP_DMA32, __GFP_MOVABLE and others) so we have to respect those. Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Jan Kara <jack@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Mel Gorman <mgorman@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Mark Fasheh <mfasheh@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jerome Marchand
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eca56ff906 |
mm, shmem: add internal shmem resident memory accounting
Currently looking at /proc/<pid>/status or statm, there is no way to distinguish shmem pages from pages mapped to a regular file (shmem pages are mapped to /dev/zero), even though their implication in actual memory use is quite different. The internal accounting currently counts shmem pages together with regular files. As a preparation to extend the userspace interfaces, this patch adds MM_SHMEMPAGES counter to mm_rss_stat to account for shmem pages separately from MM_FILEPAGES. The next patch will expose it to userspace - this patch doesn't change the exported values yet, by adding up MM_SHMEMPAGES to MM_FILEPAGES at places where MM_FILEPAGES was used before. The only user-visible change after this patch is the OOM killer message that separates the reported "shmem-rss" from "file-rss". [vbabka@suse.cz: forward-porting, tweak changelog] Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Yigal Korman
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0df9d41ab5 |
mm, dax: fix DAX deadlocks (COW fault)
DAX handling of COW faults has wrong locking sequence: dax_fault does i_mmap_lock_read do_cow_fault does i_mmap_unlock_write Ross's commit[1] missed a fix[2] that Kirill added to Matthew's commit[3]. Original COW locking logic was introduced by Matthew here[4]. This should be applied to v4.3 as well. [1] |
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Ross Zwisler
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0f90cc6609 |
mm, dax: fix DAX deadlocks
The following two locking commits in the DAX code: commit |
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Kirill A. Shutemov
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fb6dd5fa41 |
mm: use vma_is_anonymous() in create_huge_pmd() and wp_huge_pmd()
Let's use helper rather than direct check of vma->vm_ops to distinguish anonymous VMA. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Minchan Kim <minchan@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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52a2b53ffd |
mm, dax: use i_mmap_unlock_write() in do_cow_fault()
__dax_fault() takes i_mmap_lock for write. Let's pair it with write unlock on do_cow_fault() side. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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46c043ede4 |
mm: take i_mmap_lock in unmap_mapping_range() for DAX
DAX is not so special: we need i_mmap_lock to protect mapping->i_mmap. __dax_pmd_fault() uses unmap_mapping_range() shoot out zero page from all mappings. We need to drop i_mmap_lock there to avoid lock deadlock. Re-aquiring the lock should be fine since we check i_size after the point. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Matthew Wilcox
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843172978b |
dax: fix race between simultaneous faults
If two threads write-fault on the same hole at the same time, the winner of the race will return to userspace and complete their store, only to have the loser overwrite their store with zeroes. Fix this for now by taking the i_mmap_sem for write instead of read, and do so outside the call to get_block(). Now the loser of the race will see the block has already been zeroed, and will not zero it again. This severely limits our scalability. I have ideas for improving it, but those can wait for a later patch. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Matthew Wilcox
|
b96375f74a |
mm: add a pmd_fault handler
Allow non-anonymous VMAs to provide huge pages in response to a page fault. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
Oleg Nesterov
|
b533062854 |
mm: introduce vma_is_anonymous(vma) helper
special_mapping_fault() is absolutely broken. It seems it was always wrong, but this didn't matter until vdso/vvar started to use more than one page. And after this change vma_is_anonymous() becomes really trivial, it simply checks vm_ops == NULL. However, I do think the helper makes sense. There are a lot of ->vm_ops != NULL checks, the helper makes the caller's code more understandable (self-documented) and this is more grep-friendly. This patch (of 3): Preparation. Add the new simple helper, vma_is_anonymous(vma), and change handle_pte_fault() to use it. It will have more users. The name is not accurate, say a hpet_mmap()'ed vma is not anonymous. Perhaps it should be named vma_has_fault() instead. But it matches the logic in mmap.c/memory.c (see next changes). "True" just means that a page fault will use do_anonymous_page(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
Nicholas Krause
|
ca1d6c7d9d |
mm/memory.c: make tlb_next_batch() return bool
This makes the tlb_next_batch() bool due to this particular function only ever returning either one or zero as its return value. Signed-off-by: Nicholas Krause <xerofoify@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
Andrea Arcangeli
|
6b251fc96c |
userfaultfd: call handle_userfault() for userfaultfd_missing() faults
This is where the page faults must be modified to call handle_userfault() if userfaultfd_missing() is true (so if the vma->vm_flags had VM_UFFD_MISSING set). handle_userfault() then takes care of blocking the page fault and delivering it to userland. The fault flags must also be passed as parameter so the "read|write" kind of fault can be passed to userland. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Kirill A. Shutemov
|
6b7339f4c3 |
mm: avoid setting up anonymous pages into file mapping
Reading page fault handler code I've noticed that under right circumstances kernel would map anonymous pages into file mappings: if the VMA doesn't have vm_ops->fault() and the VMA wasn't fully populated on ->mmap(), kernel would handle page fault to not populated pte with do_anonymous_page(). Let's change page fault handler to use do_anonymous_page() only on anonymous VMA (->vm_ops == NULL) and make sure that the VMA is not shared. For file mappings without vm_ops->fault() or shred VMA without vm_ops, page fault on pte_none() entry would lead to SIGBUS. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
Linus Torvalds
|
1dc51b8288 |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro:
"Assorted VFS fixes and related cleanups (IMO the most interesting in
that part are f_path-related things and Eric's descriptor-related
stuff). UFS regression fixes (it got broken last cycle). 9P fixes.
fs-cache series, DAX patches, Jan's file_remove_suid() work"
[ I'd say this is much more than "fixes and related cleanups". The
file_table locking rule change by Eric Dumazet is a rather big and
fundamental update even if the patch isn't huge. - Linus ]
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
9p: cope with bogus responses from server in p9_client_{read,write}
p9_client_write(): avoid double p9_free_req()
9p: forgetting to cancel request on interrupted zero-copy RPC
dax: bdev_direct_access() may sleep
block: Add support for DAX reads/writes to block devices
dax: Use copy_from_iter_nocache
dax: Add block size note to documentation
fs/file.c: __fget() and dup2() atomicity rules
fs/file.c: don't acquire files->file_lock in fd_install()
fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
vfs: avoid creation of inode number 0 in get_next_ino
namei: make set_root_rcu() return void
make simple_positive() public
ufs: use dir_pages instead of ufs_dir_pages()
pagemap.h: move dir_pages() over there
remove the pointless include of lglock.h
fs: cleanup slight list_entry abuse
xfs: Correctly lock inode when removing suid and file capabilities
fs: Call security_ops->inode_killpriv on truncate
fs: Provide function telling whether file_remove_privs() will do anything
...
|
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Mel Gorman
|
eb3c24f305 |
mm, memcg: Try charging a page before setting page up to date
Historically memcg overhead was high even if memcg was unused. This has
improved a lot but it still showed up in a profile summary as being a
problem.
/usr/src/linux-4.0-vanilla/mm/memcontrol.c 6.6441 395842
mem_cgroup_try_charge 2.950% 175781
__mem_cgroup_count_vm_event 1.431% 85239
mem_cgroup_page_lruvec 0.456% 27156
mem_cgroup_commit_charge 0.392% 23342
uncharge_list 0.323% 19256
mem_cgroup_update_lru_size 0.278% 16538
memcg_check_events 0.216% 12858
mem_cgroup_charge_statistics.isra.22 0.188% 11172
try_charge 0.150% 8928
commit_charge 0.141% 8388
get_mem_cgroup_from_mm 0.121% 7184
That is showing that 6.64% of system CPU cycles were in memcontrol.c and
dominated by mem_cgroup_try_charge. The annotation shows that the bulk
of the cost was checking PageSwapCache which is expected to be cache hot
but is very expensive. The problem appears to be that __SetPageUptodate
is called just before the check which is a write barrier. It is
required to make sure struct page and page data is written before the
PTE is updated and the data visible to userspace. memcg charging does
not require or need the barrier but gets unfairly hit with the cost so
this patch attempts the charging before the barrier. Aside from the
accidental cost to memcg there is the added benefit that the barrier is
avoided if the page cannot be charged. When applied the relevant
profile summary is as follows.
/usr/src/linux-4.0-chargefirst-v2r1/mm/memcontrol.c 3.7907 223277
__mem_cgroup_count_vm_event 1.143% 67312
mem_cgroup_page_lruvec 0.465% 27403
mem_cgroup_commit_charge 0.381% 22452
uncharge_list 0.332% 19543
mem_cgroup_update_lru_size 0.284% 16704
get_mem_cgroup_from_mm 0.271% 15952
mem_cgroup_try_charge 0.237% 13982
memcg_check_events 0.222% 13058
mem_cgroup_charge_statistics.isra.22 0.185% 10920
commit_charge 0.140% 8235
try_charge 0.131% 7716
That brings the overhead down to 3.79% and leaves the memcg fault
accounting to the root cgroup but it's an improvement. The difference
in headline performance of the page fault microbench is marginal as
memcg is such a small component of it.
pft faults
4.0.0 4.0.0
vanilla chargefirst
Hmean faults/cpu-1 1443258.1051 ( 0.00%) 1509075.7561 ( 4.56%)
Hmean faults/cpu-3 1340385.9270 ( 0.00%) 1339160.7113 ( -0.09%)
Hmean faults/cpu-5 875599.0222 ( 0.00%) 874174.1255 ( -0.16%)
Hmean faults/cpu-7 601146.6726 ( 0.00%) 601370.9977 ( 0.04%)
Hmean faults/cpu-8 510728.2754 ( 0.00%) 510598.8214 ( -0.03%)
Hmean faults/sec-1 1432084.7845 ( 0.00%) 1497935.5274 ( 4.60%)
Hmean faults/sec-3 3943818.1437 ( 0.00%) 3941920.1520 ( -0.05%)
Hmean faults/sec-5 3877573.5867 ( 0.00%) 3869385.7553 ( -0.21%)
Hmean faults/sec-7 3991832.0418 ( 0.00%) 3992181.4189 ( 0.01%)
Hmean faults/sec-8 3987189.8167 ( 0.00%) 3986452.2204 ( -0.02%)
It's only visible at single threaded. The overhead is there for higher
threads but other factors dominate.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Miklos Szeredi
|
9bf39ab2ad |
vfs: add file_path() helper
Turn d_path(&file->f_path, ...); into file_path(file, ...); Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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David Hildenbrand
|
9ec23531fd |
sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults
Commit
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|
Boaz Harrosh
|
dd9061846a |
mm: new pfn_mkwrite same as page_mkwrite for VM_PFNMAP
This will allow FS that uses VM_PFNMAP | VM_MIXEDMAP (no page structs) to
get notified when access is a write to a read-only PFN.
This can happen if we mmap() a file then first mmap-read from it to
page-in a read-only PFN, than we mmap-write to the same page.
We need this functionality to fix a DAX bug, where in the scenario above
we fail to set ctime/mtime though we modified the file. An xfstest is
attached to this patchset that shows the failure and the fix. (A DAX
patch will follow)
This functionality is extra important for us, because upon dirtying of a
pmem page we also want to RDMA the page to a remote cluster node.
We define a new pfn_mkwrite and do not reuse page_mkwrite because
1 - The name ;-)
2 - But mainly because it would take a very long and tedious
audit of all page_mkwrite functions of VM_MIXEDMAP/VM_PFNMAP
users. To make sure they do not now CRASH. For example current
DAX code (which this is for) would crash.
If we would want to reuse page_mkwrite, We will need to first
patch all users, so to not-crash-on-no-page. Then enable this
patch. But even if I did that I would not sleep so well at night.
Adding a new vector is the safest thing to do, and is not that
expensive. an extra pointer at a static function vector per driver.
Also the new vector is better for performance, because else we
Will call all current Kernel vectors, so to:
check-ha-no-page-do-nothing and return.
No need to call it from do_shared_fault because do_wp_page is called to
change pte permissions anyway.
Signed-off-by: Yigal Korman <yigal@plexistor.com>
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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|
Konstantin Khlebnikov
|
2682582a6e |
mm/memory: also print a_ops->readpage in print_bad_pte()
A lot of filesystems use generic_file_mmap() and filemap_fault(), f_op->mmap and vm_ops->fault aren't enough to identify filesystem. This prints file name, vm_ops->fault, f_op->mmap and a_ops->readpage (which is almost always implemented and filesystem-specific). Example: [ 23.676410] BUG: Bad page map in process sh pte:1b7e6025 pmd:19bbd067 [ 23.676887] page:ffffea00006df980 count:4 mapcount:1 mapping:ffff8800196426c0 index:0x97 [ 23.677481] flags: 0x10000000000000c(referenced|uptodate) [ 23.677896] page dumped because: bad pte [ 23.678205] addr:00007f52fcb17000 vm_flags:00000075 anon_vma: (null) mapping:ffff8800196426c0 index:97 [ 23.678922] file:libc-2.19.so fault:filemap_fault mmap:generic_file_readonly_mmap readpage:v9fs_vfs_readpage [akpm@linux-foundation.org: use pr_alert, per Kirill] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Sasha Levin <sasha.levin@oracle.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jason Low
|
4db0c3c298 |
mm: remove rest of ACCESS_ONCE() usages
We converted some of the usages of ACCESS_ONCE to READ_ONCE in the mm/ tree since it doesn't work reliably on non-scalar types. This patch removes the rest of the usages of ACCESS_ONCE, and use the new READ_ONCE API for the read accesses. This makes things cleaner, instead of using separate/multiple sets of APIs. Signed-off-by: Jason Low <jason.low2@hp.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Shachar Raindel
|
93e478d4c3 |
mm: refactor do_wp_page handling of shared vma into a function
The do_wp_page function is extremely long. Extract the logic for handling a page belonging to a shared vma into a function of its own. This helps the readability of the code, without doing any functional change in it. Signed-off-by: Shachar Raindel <raindel@mellanox.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Haggai Eran <haggaie@mellanox.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Michel Lespinasse <walken@google.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Shachar Raindel
|
2f38ab2c3c |
mm: refactor do_wp_page, extract the page copy flow
In some cases, do_wp_page had to copy the page suffering a write fault to a new location. If the function logic decided that to do this, it was done by jumping with a "goto" operation to the relevant code block. This made the code really hard to understand. It is also against the kernel coding style guidelines. This patch extracts the page copy and page table update logic to a separate function. It also clean up the naming, from "gotten" to "wp_page_copy", and adds few comments. Signed-off-by: Shachar Raindel <raindel@mellanox.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Haggai Eran <haggaie@mellanox.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Michel Lespinasse <walken@google.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Shachar Raindel
|
2876680527 |
mm: refactor do_wp_page - rewrite the unlock flow
When do_wp_page is ending, in several cases it needs to unlock the pages and ptls it was accessing. Currently, this logic was "called" by using a goto jump. This makes following the control flow of the function harder. Readability was further hampered by the unlock case containing large amount of logic needed only in one of the 3 cases. Using goto for cleanup is generally allowed. However, moving the trivial unlocking flows to the relevant call sites allow deeper refactoring in the next patch. Signed-off-by: Shachar Raindel <raindel@mellanox.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Haggai Eran <haggaie@mellanox.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Michel Lespinasse <walken@google.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Shachar Raindel
|
4e047f8977 |
mm: refactor do_wp_page, extract the reuse case
Currently do_wp_page contains 265 code lines. It also contains 9 goto statements, of which 5 are targeting labels which are not cleanup related. This makes the function extremely difficult to understand. The following patches are an attempt at breaking the function to its basic components, and making it easier to understand. The patches are straight forward function extractions from do_wp_page. As we extract functions, we remove unneeded parameters and simplify the code as much as possible. However, the functionality is supposed to remain completely unchanged. The patches also attempt to document the functionality of each extracted function. In patch 2, we split the unlock logic to the contain logic relevant to specific needs of each use case, instead of having huge number of conditional decisions in a single unlock flow. This patch (of 4): When do_wp_page is ending, in several cases it needs to reuse the existing page. This is achieved by making the page table writable, and possibly updating the page-cache state. Currently, this logic was "called" by using a goto jump. This makes following the control flow of the function harder. It is also against the coding style guidelines for using goto. As the code can easily be refactored into a specialized function, refactor it out and simplify the code flow in do_wp_page. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Andi Kleen <ak@linux.intel.com> Acked-by: Haggai Eran <haggaie@mellanox.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Feiner <pfeiner@google.com> Cc: Michel Lespinasse <walken@google.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Mel Gorman
|
074c238177 |
mm: numa: slow PTE scan rate if migration failures occur
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: Mel Gorman <mgorman@suse.de> Reported-by: Dave Chinner <david@fromorbit.com> Tested-by: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
|
b191f9b106 |
mm: numa: preserve PTE write permissions across a NUMA hinting fault
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: Mel Gorman <mgorman@suse.de>
Reported-by: Dave Chinner <david@fromorbit.com>
Tested-by: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Mel Gorman
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bea66fbd11 |
mm: numa: group related processes based on VMA flags instead of page table flags
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 |
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Linus Torvalds
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53da3bc2ba |
mm: fix up numa read-only thread grouping logic
Dave Chinner reported that commit
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Matthew Wilcox
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2e4cdab058 |
mm: allow page fault handlers to perform the COW
Currently COW of an XIP file is done by first bringing in a read-only mapping, then retrying the fault and copying the page. It is much more efficient to tell the fault handler that a COW is being attempted (by passing in the pre-allocated page in the vm_fault structure), and allow the handler to perform the COW operation itself. The handler cannot insert the page itself if there is already a read-only mapping at that address, so allow the handler to return VM_FAULT_LOCKED and set the fault_page to be NULL. This indicates to the MM code that the i_mmap_lock is held instead of the page lock. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Matthew Wilcox
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283307c760 |
mm: fix XIP fault vs truncate race
DAX is a replacement for the variation of XIP currently supported by the ext2 filesystem. We have three different things in the tree called 'XIP', and the new focus is on access to data rather than executables, so a name change was in order. DAX stands for Direct Access. The X is for eXciting. The new focus on data access has resulted in more careful attention to races that exist in the current XIP code, but are not hit by the use-case that it was designed for. XIP's architecture worked fine for ext2, but DAX is architected to work with modern filsystems such as ext4 and XFS. DAX is not intended for use with btrfs; the value that btrfs adds relies on manipulating data and writing data to different locations, while DAX's value is for write-in-place and keeping the kernel from touching the data. DAX was developed in order to support NV-DIMMs, but it's become clear that its usefuless extends beyond NV-DIMMs and there are several potential customers including the tracing machinery. Other people want to place the kernel log in an area of memory, as long as they have a BIOS that does not clear DRAM on reboot. Patch 1 is a bug fix, probably worth including in 3.18. Patches 2 & 3 are infrastructure for DAX. Patches 4-8 replace the XIP code with its DAX equivalents, transforming ext2 to use the DAX code as we go. Note that patch 10 is the Documentation patch. Patches 9-15 clean up after the XIP code, removing the infrastructure that is no longer needed and renaming various XIP things to DAX. Most of these patches were added after Jan found things he didn't like in an earlier version of the ext4 patch ... that had been copied from ext2. So ext2 i being transformed to do things the same way that ext4 will later. The ability to mount ext2 filesystems with the 'xip' option is retained, although the 'dax' option is now preferred. Patch 16 adds some DAX infrastructure to support ext4. Patch 17 adds DAX support to ext4. It is broadly similar to ext2's DAX support, but it is more efficient than ext4's due to its support for unwritten extents. Patch 18 is another cleanup patch renaming XIP to DAX. My thanks to Mathieu Desnoyers for his reviews of the v11 patchset. Most of the changes below were based on his feedback. This patch (of 18): Pagecache faults recheck i_size after taking the page lock to ensure that the fault didn't race against a truncate. We don't have a page to lock in the XIP case, so use i_mmap_lock_read() instead. It is locked in the truncate path in unmap_mapping_range() after updating i_size. So while we hold it in the fault path, we are guaranteed that either i_size has already been updated in the truncate path, or that the truncate will subsequently call zap_page_range_single() and so remove the mapping we have just inserted. There is a window of time in which i_size has been reduced and the thread has a mapping to a page which will be removed from the file, but this is harmless as the page will not be allocated to a different purpose before the thread's access to it is revoked. [akpm@linux-foundation.org: switch to i_mmap_lock_read(), add comment in unmap_single_vma()] Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Grazvydas Ignotas
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9cb12d7b4c |
mm/memory.c: actually remap enough memory
For whatever reason, generic_access_phys() only remaps one page, but
actually allows to access arbitrary size. It's quite easy to trigger
large reads, like printing out large structure with gdb, which leads to a
crash. Fix it by remapping correct size.
Fixes:
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Mel Gorman
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c0e7cad9f2 |
mm: numa: add paranoid check around pte_protnone_numa
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: Mel 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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e944fd67b6 |
mm: numa: do not trap faults on the huge zero page
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: Mel 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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4d94246699 |
mm: convert p[te|md]_mknonnuma and remaining page table manipulations
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: Mel Gorman <mgorman@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Tested-by: Sasha 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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8a0516ed8b |
mm: convert p[te|md]_numa users to p[te|md]_protnone_numa
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: Mel Gorman <mgorman@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Sasha 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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dc6c9a35b6 |
mm: account pmd page tables to the process
Dave noticed that unprivileged process can allocate significant amount of
memory -- >500 MiB on x86_64 -- and stay unnoticed by oom-killer and
memory cgroup. The trick is to allocate a lot of PMD page tables. Linux
kernel doesn't account PMD tables to the process, only PTE.
The use-cases below use few tricks to allocate a lot of PMD page tables
while keeping VmRSS and VmPTE low. oom_score for the process will be 0.
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#define PUD_SIZE (1UL << 30)
#define PMD_SIZE (1UL << 21)
#define NR_PUD 130000
int main(void)
{
char *addr = NULL;
unsigned long i;
prctl(PR_SET_THP_DISABLE);
for (i = 0; i < NR_PUD ; i++) {
addr = mmap(addr + PUD_SIZE, PUD_SIZE, PROT_WRITE|PROT_READ,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
if (addr == MAP_FAILED) {
perror("mmap");
break;
}
*addr = 'x';
munmap(addr, PMD_SIZE);
mmap(addr, PMD_SIZE, PROT_WRITE|PROT_READ,
MAP_ANONYMOUS|MAP_PRIVATE|MAP_FIXED, -1, 0);
if (addr == MAP_FAILED)
perror("re-mmap"), exit(1);
}
printf("PID %d consumed %lu KiB in PMD page tables\n",
getpid(), i * 4096 >> 10);
return pause();
}
The patch addresses the issue by account PMD tables to the process the
same way we account PTE.
The main place where PMD tables is accounted is __pmd_alloc() and
free_pmd_range(). But there're few corner cases:
- HugeTLB can share PMD page tables. The patch handles by accounting
the table to all processes who share it.
- x86 PAE pre-allocates few PMD tables on fork.
- Architectures with FIRST_USER_ADDRESS > 0. We need to adjust sanity
check on exit(2).
Accounting only happens on configuration where PMD page table's level is
present (PMD is not folded). As with nr_ptes we use per-mm counter. The
counter value is used to calculate baseline for badness score by
oom-killer.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: David Rientjes <rientjes@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds
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992de5a8ec |
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:
"Bite-sized chunks this time, to avoid the MTA ratelimiting woes.
- fs/notify updates
- ocfs2
- some of MM"
That laconic "some MM" is mainly the removal of remap_file_pages(),
which is a big simplification of the VM, and which gets rid of a *lot*
of random cruft and special cases because we no longer support the
non-linear mappings that it used.
From a user interface perspective, nothing has changed, because the
remap_file_pages() syscall still exists, it's just done by emulating the
old behavior by creating a lot of individual small mappings instead of
one non-linear one.
The emulation is slower than the old "native" non-linear mappings, but
nobody really uses or cares about remap_file_pages(), and simplifying
the VM is a big advantage.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (78 commits)
memcg: zap memcg_slab_caches and memcg_slab_mutex
memcg: zap memcg_name argument of memcg_create_kmem_cache
memcg: zap __memcg_{charge,uncharge}_slab
mm/page_alloc.c: place zone_id check before VM_BUG_ON_PAGE check
mm: hugetlb: fix type of hugetlb_treat_as_movable variable
mm, hugetlb: remove unnecessary lower bound on sysctl handlers"?
mm: memory: merge shared-writable dirtying branches in do_wp_page()
mm: memory: remove ->vm_file check on shared writable vmas
xtensa: drop _PAGE_FILE and pte_file()-related helpers
x86: drop _PAGE_FILE and pte_file()-related helpers
unicore32: drop pte_file()-related helpers
um: drop _PAGE_FILE and pte_file()-related helpers
tile: drop pte_file()-related helpers
sparc: drop pte_file()-related helpers
sh: drop _PAGE_FILE and pte_file()-related helpers
score: drop _PAGE_FILE and pte_file()-related helpers
s390: drop pte_file()-related helpers
parisc: drop _PAGE_FILE and pte_file()-related helpers
openrisc: drop _PAGE_FILE and pte_file()-related helpers
nios2: drop _PAGE_FILE and pte_file()-related helpers
...
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