From: Aneesh Kumar K.V Date: Thu, 3 May 2012 05:43:34 +0000 (+1000) Subject: hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages X-Git-Tag: next-20120503~2^2~230 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1cbe3d3bba1cb08aee1905714d435eccdd31a654;p=karo-tx-linux.git hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages Use an mmu_gather instead of a temporary linked list for accumulating pages when we unmap a hugepage range. This also allows us to get rid of i_mmap_mutex unmap_hugepage_range in the following patch. Signed-off-by: Aneesh Kumar K.V Reviewed-by: KAMEZAWA Hiroyuki Cc: Hillf Danton Cc: Michal Hocko Cc: Andrea Arcangeli Cc: Johannes Weiner Signed-off-by: Andrew Morton --- diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 001ef01d2fe2..63b59d684cf9 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -416,8 +416,8 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff) else v_offset = 0; - __unmap_hugepage_range(vma, - vma->vm_start + v_offset, vma->vm_end, NULL); + unmap_hugepage_range(vma, vma->vm_start + v_offset, + vma->vm_end, NULL); } } diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 217f52859fa7..830306c10f14 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -40,9 +40,9 @@ int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int, unsigned int flags); void unmap_hugepage_range(struct vm_area_struct *, - unsigned long, unsigned long, struct page *); -void __unmap_hugepage_range(struct vm_area_struct *, - unsigned long, unsigned long, struct page *); + unsigned long, unsigned long, struct page *); +void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *, + unsigned long, unsigned long, struct page *); int hugetlb_prefault(struct address_space *, struct vm_area_struct *); void hugetlb_report_meminfo(struct seq_file *); int hugetlb_report_node_meminfo(int, char *); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 43c9efac096b..674982c37afa 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -24,8 +24,9 @@ #include #include -#include +#include +#include #include #include #include "internal.h" @@ -2301,30 +2302,26 @@ static int is_hugetlb_entry_hwpoisoned(pte_t pte) return 0; } -void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, - unsigned long end, struct page *ref_page) +void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct page *ref_page) { + int force_flush = 0; struct mm_struct *mm = vma->vm_mm; unsigned long address; pte_t *ptep; pte_t pte; struct page *page; - struct page *tmp; struct hstate *h = hstate_vma(vma); unsigned long sz = huge_page_size(h); - /* - * A page gathering list, protected by per file i_mmap_mutex. The - * lock is used to avoid list corruption from multiple unmapping - * of the same page since we are using page->lru. - */ - LIST_HEAD(page_list); - WARN_ON(!is_vm_hugetlb_page(vma)); BUG_ON(start & ~huge_page_mask(h)); BUG_ON(end & ~huge_page_mask(h)); + tlb_start_vma(tlb, vma); mmu_notifier_invalidate_range_start(mm, start, end); +again: spin_lock(&mm->page_table_lock); for (address = start; address < end; address += sz) { ptep = huge_pte_offset(mm, address); @@ -2363,30 +2360,45 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, } pte = huge_ptep_get_and_clear(mm, address, ptep); + tlb_remove_tlb_entry(tlb, ptep, address); if (pte_dirty(pte)) set_page_dirty(page); - list_add(&page->lru, &page_list); + page_remove_rmap(page); + force_flush = !__tlb_remove_page(tlb, page); + if (force_flush) + break; /* Bail out after unmapping reference page if supplied */ if (ref_page) break; } - flush_tlb_range(vma, start, end); spin_unlock(&mm->page_table_lock); - mmu_notifier_invalidate_range_end(mm, start, end); - list_for_each_entry_safe(page, tmp, &page_list, lru) { - page_remove_rmap(page); - list_del(&page->lru); - put_page(page); + /* + * mmu_gather ran out of room to batch pages, we break out of + * the PTE lock to avoid doing the potential expensive TLB invalidate + * and page-free while holding it. + */ + if (force_flush) { + force_flush = 0; + tlb_flush_mmu(tlb); + if (address < end && !ref_page) + goto again; } + mmu_notifier_invalidate_range_end(mm, start, end); + tlb_end_vma(tlb, vma); } void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page) { - mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); - __unmap_hugepage_range(vma, start, end, ref_page); - mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); + struct mm_struct *mm; + struct mmu_gather tlb; + + mm = vma->vm_mm; + + tlb_gather_mmu(&tlb, mm, 0); + __unmap_hugepage_range(&tlb, vma, start, end, ref_page); + tlb_finish_mmu(&tlb, start, end); } /* @@ -2431,9 +2443,8 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, * from the time of fork. This would look like data corruption */ if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) - __unmap_hugepage_range(iter_vma, - address, address + huge_page_size(h), - page); + unmap_hugepage_range(iter_vma, address, + address + huge_page_size(h), page); } mutex_unlock(&mapping->i_mmap_mutex); diff --git a/mm/memory.c b/mm/memory.c index 706a27441b03..f9cfa908c5c9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1329,8 +1329,11 @@ static void unmap_single_vma(struct mmu_gather *tlb, * Since no pte has actually been setup, it is * safe to do nothing in this case. */ - if (vma->vm_file) - unmap_hugepage_range(vma, start, end, NULL); + if (vma->vm_file) { + mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); + __unmap_hugepage_range(tlb, vma, start, end, NULL); + mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); + } } else unmap_page_range(tlb, vma, start, end, details); }