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Commit 0c942a45 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

[PATCH] mm: msync_pte_range progress 



Use latency breaking in msync_pte_range like that in copy_pte_range, instead
of the ugly CONFIG_PREEMPT filemap_msync alternatives.

Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e040f218

mm/msync.c

+14 −24
Original line number Diff line number Diff line
@@ -26,12 +26,21 @@ static void msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, 
				unsigned long addr, unsigned long end)

{

	pte_t *pte;

	int progress = 0;



again:

	pte = pte_offset_map(pmd, addr);

	do {

		unsigned long pfn;

		struct page *page;



		if (progress >= 64) {

			progress = 0;

			if (need_resched() ||

			    need_lockbreak(&vma->vm_mm->page_table_lock))

				break;

		}

		progress++;

		if (!pte_present(*pte))

			continue;

		if (!pte_maybe_dirty(*pte))
@@ -46,8 +55,12 @@ static void msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, 
		if (ptep_clear_flush_dirty(vma, addr, pte) ||

		    page_test_and_clear_dirty(page))

			set_page_dirty(page);

		progress += 3;

	} while (pte++, addr += PAGE_SIZE, addr != end);

	pte_unmap(pte - 1);

	cond_resched_lock(&vma->vm_mm->page_table_lock);

	if (addr != end)

		goto again;

}



static inline void msync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
@@ -106,29 +119,6 @@ static void msync_page_range(struct vm_area_struct *vma, 
	spin_unlock(&mm->page_table_lock);

}



#ifdef CONFIG_PREEMPT

static inline void filemap_msync(struct vm_area_struct *vma,

				 unsigned long addr, unsigned long end)

{

	const size_t chunk = 64 * 1024;	/* bytes */

	unsigned long next;



	do {

		next = addr + chunk;

		if (next > end || next < addr)

			next = end;

		msync_page_range(vma, addr, next);

		cond_resched();

	} while (addr = next, addr != end);

}

#else

static inline void filemap_msync(struct vm_area_struct *vma,

				 unsigned long addr, unsigned long end)

{

	msync_page_range(vma, addr, end);

}

#endif



/*

 * MS_SYNC syncs the entire file - including mappings.

 *
@@ -150,7 +140,7 @@ static int msync_interval(struct vm_area_struct *vma, 
		return -EBUSY;



	if (file && (vma->vm_flags & VM_SHARED)) {

		filemap_msync(vma, addr, end);

		msync_page_range(vma, addr, end);



		if (flags & MS_SYNC) {

			struct address_space *mapping = file->f_mapping;