The patch titled Subject: mm/khugepaged: collapse_shmem() remember to clear holes has been added to the -mm tree. Its filename is mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch
This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-khugepaged-collapse_shmem-rememb... and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-collapse_shmem-rememb...
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------------------------------------------------------ From: Hugh Dickins hughd@google.com Subject: mm/khugepaged: collapse_shmem() remember to clear holes
Huge tmpfs testing reminds us that there is no __GFP_ZERO in the gfp flags khugepaged uses to allocate a huge page - in all common cases it would just be a waste of effort - so collapse_shmem() must remember to clear out any holes that it instantiates.
The obvious place to do so, where they are put into the page cache tree, is not a good choice: because interrupts are disabled there. Leave it until further down, once success is assured, where the other pages are copied (before setting PageUptodate).
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261525080.2275@eggly.anvils Fixes: f3f0e1d2150b2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Hugh Dickins hughd@google.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Jerome Glisse jglisse@redhat.com Cc: Konstantin Khlebnikov khlebnikov@yandex-team.ru Cc: Matthew Wilcox willy@infradead.org Cc: stable@vger.kernel.org [4.8+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
--- a/mm/khugepaged.c~mm-khugepaged-collapse_shmem-remember-to-clear-holes +++ a/mm/khugepaged.c @@ -1467,7 +1467,12 @@ xa_unlocked: * Replacing old pages with new one has succeeded, now we * need to copy the content and free the old pages. */ + index = start; list_for_each_entry_safe(page, tmp, &pagelist, lru) { + while (index < page->index) { + clear_highpage(new_page + (index % HPAGE_PMD_NR)); + index++; + } copy_highpage(new_page + (page->index % HPAGE_PMD_NR), page); list_del(&page->lru); @@ -1477,6 +1482,11 @@ xa_unlocked: ClearPageActive(page); ClearPageUnevictable(page); put_page(page); + index++; + } + while (index < end) { + clear_highpage(new_page + (index % HPAGE_PMD_NR)); + index++; }
local_irq_disable(); _
Patches currently in -mm which might be from hughd@google.com are
mm-huge_memory-rename-freeze_page-to-unmap_page.patch mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch mm-khugepaged-minor-reorderings-in-collapse_shmem.patch mm-khugepaged-collapse_shmem-without-freezing-new_page.patch mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch mm-khugepaged-fix-the-xas_create_range-error-path.patch mm-put_and_wait_on_page_locked-while-page-is-migrated.patch