Subject: [merged] thp-move-preallocated-pte-page-table-on-move_huge_pmd.patch removed from -mm tree To: kirill.shutemov@xxxxxxxxxxxxxxx,avagin@xxxxxxxxxx,n-horiguchi@xxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Mon, 16 Dec 2013 12:39:40 -0800 The patch titled Subject: thp: move preallocated PTE page table on move_huge_pmd() has been removed from the -mm tree. Its filename was thp-move-preallocated-pte-page-table-on-move_huge_pmd.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Subject: thp: move preallocated PTE page table on move_huge_pmd() Andrey Wagin reported crash on VM_BUG_ON() in pgtable_pmd_page_dtor() with fallowing backtrace: [<ffffffff8119427f>] free_pgd_range+0x2bf/0x410 [<ffffffff8119449e>] free_pgtables+0xce/0x120 [<ffffffff8119b900>] unmap_region+0xe0/0x120 [<ffffffff811a0036>] ? move_page_tables+0x526/0x6b0 [<ffffffff8119d6a9>] do_munmap+0x249/0x360 [<ffffffff811a0304>] move_vma+0x144/0x270 [<ffffffff811a07e9>] SyS_mremap+0x3b9/0x510 [<ffffffff8172d512>] system_call_fastpath+0x16/0x1b The crash can be reproduce with this test case: #define _GNU_SOURCE #include <sys/mman.h> #include <stdio.h> #include <unistd.h> #define MB (1024 * 1024UL) #define GB (1024 * MB) int main(int argc, char **argv) { char *p; int i; p = mmap((void *) GB, 10 * MB, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0); for (i = 0; i < 10 * MB; i += 4096) p[i] = 1; mremap(p, 10 * MB, 10 * MB, MREMAP_FIXED | MREMAP_MAYMOVE, 2 * GB); return 0; } Due to split PMD lock, we now store preallocated PTE tables for THP pages per-PMD table. It means we need to move them to other PMD table if huge PMD moved there. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reported-by: Andrey Vagin <avagin@xxxxxxxxxx> Tested-by: Andrey Vagin <avagin@xxxxxxxxxx> Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff -puN mm/huge_memory.c~thp-move-preallocated-pte-page-table-on-move_huge_pmd mm/huge_memory.c --- a/mm/huge_memory.c~thp-move-preallocated-pte-page-table-on-move_huge_pmd +++ a/mm/huge_memory.c @@ -1481,8 +1481,18 @@ int move_huge_pmd(struct vm_area_struct pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); VM_BUG_ON(!pmd_none(*new_pmd)); set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); - if (new_ptl != old_ptl) + if (new_ptl != old_ptl) { + pgtable_t pgtable; + + /* + * Move preallocated PTE page table if new_pmd is on + * different PMD page table. + */ + pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); + pgtable_trans_huge_deposit(mm, new_pmd, pgtable); + spin_unlock(new_ptl); + } spin_unlock(old_ptl); } out: _ Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are mm-create-a-separate-slab-for-page-ptl-allocation-try-two.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html