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2016-07-26mm, thp: convert from optimistic swapin collapsing to conservativeEbru Akagunduz
To detect whether khugepaged swapin is worthwhile, this patch checks the amount of young pages. There should be at least half of HPAGE_PMD_NR to swapin. Link: http://lkml.kernel.org/r/1468109451-1615-1-git-send-email-ebru.akagunduz@gmail.com Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> Suggested-by: Minchan Kim <minchan@kernel.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26mm, thp: fix comment inconsistency for swapin readahead functionsEbru Akagunduz
After fixing swapin issues, comment lines stayed as in old version. This patch updates the comments. Link: http://lkml.kernel.org/r/1468109345-32258-1-git-send-email-ebru.akagunduz@gmail.com Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Mel Gorman <mgorman@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHEKirill A. Shutemov
For file mappings, we don't deposit page tables on THP allocation because it's not strictly required to implement split_huge_pmd(): we can just clear pmd and let following page faults to reconstruct the page table. But Power makes use of deposited page table to address MMU quirk. Let's hide THP page cache, including huge tmpfs, under separate config option, so it can be forbidden on Power. We can revert the patch later once solution for Power found. Link: http://lkml.kernel.org/r/1466021202-61880-36-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26khugepaged: add support of collapse for tmpfs/shmem pagesKirill A. Shutemov
This patch extends khugepaged to support collapse of tmpfs/shmem pages. We share fair amount of infrastructure with anon-THP collapse. Few design points: - First we are looking for VMA which can be suitable for mapping huge page; - If the VMA maps shmem file, the rest scan/collapse operations operates on page cache, not on page tables as in anon VMA case. - khugepaged_scan_shmem() finds a range which is suitable for huge page. The scan is lockless and shouldn't disturb system too much. - once the candidate for collapse is found, collapse_shmem() attempts to create a huge page: + scan over radix tree, making the range point to new huge page; + new huge page is not-uptodate, locked and freezed (refcount is 0), so nobody can touch them until we say so. + we swap in pages during the scan. khugepaged_scan_shmem() filters out ranges with more than khugepaged_max_ptes_swap swapped out pages. It's HPAGE_PMD_NR/8 by default. + old pages are isolated, unmapped and put to local list in case to be restored back if collapse failed. - if collapse succeed, we retract pte page tables from VMAs where huge pages mapping is possible. The huge page will be mapped as PMD on next minor fault into the range. Link: http://lkml.kernel.org/r/1466021202-61880-35-git-send-email-kirill.shutemov@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>
2016-07-26khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()Kirill A. Shutemov
Both variants of khugepaged_alloc_page() do up_read(&mm->mmap_sem) first: no point keep it inside the function. Link: http://lkml.kernel.org/r/1466021202-61880-33-git-send-email-kirill.shutemov@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>
2016-07-26thp: extract khugepaged from mm/huge_memory.cKirill A. Shutemov
khugepaged implementation grew to the point when it deserve separate file in source. Let's move it to mm/khugepaged.c. Link: http://lkml.kernel.org/r/1466021202-61880-32-git-send-email-kirill.shutemov@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>