The patch titled Subject: mm/mremap: it is sure to have enough space when extent meets requirement has been added to the -mm tree. Its filename is mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Subject: mm/mremap: it is sure to have enough space when extent meets requirement old_end is passed to these two function to check whether there is enough space to do the move, while this check is done before invoking these functions. These two functions only would be invoked when extent meets the requirement and there is one check before invoking these functions: if (extent > old_end - old_addr) extent = old_end - old_addr; This implies (old_end - old_addr) won't fail the check in these two functions. Link: http://lkml.kernel.org/r/20200117232254.2792-3-richardw.yang@xxxxxxxxxxxxxxx Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Cc: Thomas Hellstrom <thellstrom@xxxxxxxxxx> Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/huge_mm.h | 2 +- mm/huge_memory.c | 7 ++----- mm/mremap.c | 11 ++++------- 3 files changed, 7 insertions(+), 13 deletions(-) --- a/include/linux/huge_mm.h~mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement +++ a/include/linux/huge_mm.h @@ -42,7 +42,7 @@ extern int mincore_huge_pmd(struct vm_ar unsigned long addr, unsigned long end, unsigned char *vec); extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, unsigned long old_end, + unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd); extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, pgprot_t newprot, --- a/mm/huge_memory.c~mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement +++ a/mm/huge_memory.c @@ -1871,17 +1871,14 @@ static pmd_t move_soft_dirty_pmd(pmd_t p } bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, unsigned long old_end, - pmd_t *old_pmd, pmd_t *new_pmd) + unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) { spinlock_t *old_ptl, *new_ptl; pmd_t pmd; struct mm_struct *mm = vma->vm_mm; bool force_flush = false; - if ((old_addr & ~HPAGE_PMD_MASK) || - (new_addr & ~HPAGE_PMD_MASK) || - old_end - old_addr < HPAGE_PMD_SIZE) + if ((old_addr & ~HPAGE_PMD_MASK) || (new_addr & ~HPAGE_PMD_MASK)) return false; /* --- a/mm/mremap.c~mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement +++ a/mm/mremap.c @@ -193,16 +193,13 @@ static void move_ptes(struct vm_area_str #ifdef CONFIG_HAVE_MOVE_PMD static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr, - unsigned long new_addr, unsigned long old_end, - pmd_t *old_pmd, pmd_t *new_pmd) + unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd) { spinlock_t *old_ptl, *new_ptl; struct mm_struct *mm = vma->vm_mm; pmd_t pmd; - if ((old_addr & ~PMD_MASK) || - (new_addr & ~PMD_MASK) || - old_end - old_addr < PMD_SIZE) + if ((old_addr & ~PMD_MASK) || (new_addr & ~PMD_MASK)) return false; /* @@ -274,7 +271,7 @@ unsigned long move_page_tables(struct vm if (need_rmap_locks) take_rmap_locks(vma); moved = move_huge_pmd(vma, old_addr, new_addr, - old_end, old_pmd, new_pmd); + old_pmd, new_pmd); if (need_rmap_locks) drop_rmap_locks(vma); if (moved) @@ -294,7 +291,7 @@ unsigned long move_page_tables(struct vm if (need_rmap_locks) take_rmap_locks(vma); moved = move_normal_pmd(vma, old_addr, new_addr, - old_end, old_pmd, new_pmd); + old_pmd, new_pmd); if (need_rmap_locks) drop_rmap_locks(vma); if (moved) _ Patches currently in -mm which might be from richardw.yang@xxxxxxxxxxxxxxx are mm-thp-remove-the-defer-list-related-code-since-this-will-not-happen.patch mm-gupc-use-is_vm_hugetlb_page-to-check-whether-to-follow-huge.patch mm-mremap-format-the-check-in-move_normal_pmd-same-as-move_huge_pmd.patch mm-mremap-it-is-sure-to-have-enough-space-when-extent-meets-requirement.patch mm-mremap-use-pmd_addr_end-to-calculate-next-in-move_page_tables.patch mm-mremap-calculate-extent-in-one-place.patch mm-mremap-start-addresses-are-properly-aligned.patch mm-huge_memoryc-use-head-to-check-huge-zero-page.patch mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page.patch mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch mm-remove-dead-code-totalram_pages_set.patch