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mm/rmap: calculate page offset when needed 

Call page_to_pgoff() to get the page offset once we are sure we actually
need it, and any very obvious initial function checks have passed.
Trivial micro-optimization, and potentially save some cycles.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Davidlohr Bueso 2014-12-12 16:55:04 -08:00 committed by Linus Torvalds
parent 2847cf95c6
commit b258d86065
1 changed files with 4 additions and 2 deletions
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6
mm/rmap.c
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@ -1635,7 +1635,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
{
struct anon_vma *anon_vma;
pgoff_t pgoff = page_to_pgoff(page);
pgoff_t pgoff;
struct anon_vma_chain *avc;
int ret = SWAP_AGAIN;
@ -1643,6 +1643,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
if (!anon_vma)
return ret;
pgoff = page_to_pgoff(page);
anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
struct vm_area_struct *vma = avc->vma;
unsigned long address = vma_address(page, vma);
@ -1676,7 +1677,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
{
struct address_space *mapping = page->mapping;
pgoff_t pgoff = page_to_pgoff(page);
pgoff_t pgoff;
struct vm_area_struct *vma;
int ret = SWAP_AGAIN;
@ -1691,6 +1692,7 @@ static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
if (!mapping)
return ret;
pgoff = page_to_pgoff(page);
i_mmap_lock_read(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
unsigned long address = vma_address(page, vma);