From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964818AbWFSRxv (ORCPT ); Mon, 19 Jun 2006 13:53:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964812AbWFSRxs (ORCPT ); Mon, 19 Jun 2006 13:53:48 -0400 Received: from amsfep17-int.chello.nl ([213.46.243.15]:5273 "EHLO amsfep12-int.chello.nl") by vger.kernel.org with ESMTP id S964805AbWFSRx2 (ORCPT ); Mon, 19 Jun 2006 13:53:28 -0400 From: Peter Zijlstra To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Hugh Dickins , Andrew Morton , David Howells , Peter Zijlstra , Christoph Lameter , Martin Bligh , Nick Piggin , Linus Torvalds Date: Mon, 19 Jun 2006 19:53:15 +0200 Message-Id: <20060619175315.24655.45123.sendpatchset@lappy> In-Reply-To: <20060619175243.24655.76005.sendpatchset@lappy> References: <20060619175243.24655.76005.sendpatchset@lappy> Subject: [PATCH 3/6] mm: msync() cleanup Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra With the tracking of dirty pages properly done now, msync doesn't need to scan the PTEs anymore to determine the dirty status. Signed-off-by: Peter Zijlstra mm/msync.c | 129 ++++--------------------------------------------------------- 1 file changed, 9 insertions(+), 120 deletions(-) Index: 2.6-mm/mm/msync.c =================================================================== --- 2.6-mm.orig/mm/msync.c 2006-06-19 16:21:13.000000000 +0200 +++ 2.6-mm/mm/msync.c 2006-06-19 16:21:21.000000000 +0200 @@ -20,109 +20,14 @@ #include #include -static unsigned long msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, - unsigned long addr, unsigned long end) -{ - pte_t *pte; - spinlock_t *ptl; - int progress = 0; - unsigned long ret = 0; - -again: - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); - do { - struct page *page; - - if (progress >= 64) { - progress = 0; - if (need_resched() || need_lockbreak(ptl)) - break; - } - progress++; - if (!pte_present(*pte)) - continue; - if (!pte_maybe_dirty(*pte)) - continue; - page = vm_normal_page(vma, addr, *pte); - if (!page) - continue; - if (ptep_clear_flush_dirty(vma, addr, pte) || - page_test_and_clear_dirty(page)) - ret += set_page_dirty(page); - progress += 3; - } while (pte++, addr += PAGE_SIZE, addr != end); - pte_unmap_unlock(pte - 1, ptl); - cond_resched(); - if (addr != end) - goto again; - return ret; -} - -static inline unsigned long msync_pmd_range(struct vm_area_struct *vma, - pud_t *pud, unsigned long addr, unsigned long end) -{ - pmd_t *pmd; - unsigned long next; - unsigned long ret = 0; - - pmd = pmd_offset(pud, addr); - do { - next = pmd_addr_end(addr, end); - if (pmd_none_or_clear_bad(pmd)) - continue; - ret += msync_pte_range(vma, pmd, addr, next); - } while (pmd++, addr = next, addr != end); - return ret; -} - -static inline unsigned long msync_pud_range(struct vm_area_struct *vma, - pgd_t *pgd, unsigned long addr, unsigned long end) -{ - pud_t *pud; - unsigned long next; - unsigned long ret = 0; - - pud = pud_offset(pgd, addr); - do { - next = pud_addr_end(addr, end); - if (pud_none_or_clear_bad(pud)) - continue; - ret += msync_pmd_range(vma, pud, addr, next); - } while (pud++, addr = next, addr != end); - return ret; -} - -static unsigned long msync_page_range(struct vm_area_struct *vma, - unsigned long addr, unsigned long end) -{ - pgd_t *pgd; - unsigned long next; - unsigned long ret = 0; - - /* For hugepages we can't go walking the page table normally, - * but that's ok, hugetlbfs is memory based, so we don't need - * to do anything more on an msync(). - */ - if (vma->vm_flags & VM_HUGETLB) - return 0; - - BUG_ON(addr >= end); - pgd = pgd_offset(vma->vm_mm, addr); - flush_cache_range(vma, addr, end); - do { - next = pgd_addr_end(addr, end); - if (pgd_none_or_clear_bad(pgd)) - continue; - ret += msync_pud_range(vma, pgd, addr, next); - } while (pgd++, addr = next, addr != end); - return ret; -} - /* * MS_SYNC syncs the entire file - including mappings. * - * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just - * marks the relevant pages dirty. The application may now run fsync() to + * MS_ASYNC does not start I/O (it used to, up to 2.5.67). + * Nor does it marks the relevant pages dirty (it used to up to 2.6.17). + * Now it doesn't do anything, since dirty pages are properly tracked. + * + * The application may now run fsync() to * write out the dirty pages and wait on the writeout and check the result. * Or the application may run fadvise(FADV_DONTNEED) against the fd to start * async writeout immediately. @@ -130,16 +35,11 @@ static unsigned long msync_page_range(st * applications. */ static int msync_interval(struct vm_area_struct *vma, unsigned long addr, - unsigned long end, int flags, - unsigned long *nr_pages_dirtied) + unsigned long end, int flags) { - struct file *file = vma->vm_file; - if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) return -EBUSY; - if (file && (vma->vm_flags & VM_SHARED)) - *nr_pages_dirtied = msync_page_range(vma, addr, end); return 0; } @@ -178,7 +78,6 @@ asmlinkage long sys_msync(unsigned long goto out_unlock; } do { - unsigned long nr_pages_dirtied = 0; struct file *file; /* Here start < vma->vm_end. */ @@ -189,8 +88,7 @@ asmlinkage long sys_msync(unsigned long /* Here vma->vm_start <= start < vma->vm_end. */ if (end <= vma->vm_end) { if (start < end) { - error = msync_interval(vma, start, end, flags, - &nr_pages_dirtied); + error = msync_interval(vma, start, end, flags); if (error) goto out_unlock; } @@ -198,22 +96,13 @@ asmlinkage long sys_msync(unsigned long done = 1; } else { /* Here vma->vm_start <= start < vma->vm_end < end. */ - error = msync_interval(vma, start, vma->vm_end, flags, - &nr_pages_dirtied); + error = msync_interval(vma, start, vma->vm_end, flags); if (error) goto out_unlock; } file = vma->vm_file; start = vma->vm_end; - if ((flags & MS_ASYNC) && file && nr_pages_dirtied) { - get_file(file); - up_read(¤t->mm->mmap_sem); - balance_dirty_pages_ratelimited_nr(file->f_mapping, - nr_pages_dirtied); - fput(file); - down_read(¤t->mm->mmap_sem); - vma = find_vma(current->mm, start); - } else if ((flags & MS_SYNC) && file && + if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) { get_file(file); up_read(¤t->mm->mmap_sem);