Commit 5a9bbdcd authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds

mm: don't waste swap on locked pages

try_to_unmap always fails on a page found in a VM_LOCKED vma (unless
migrating), and recycles it back to the active list.  But if it's an
anonymous page, we've already allocated swap to it: just wasting swap.
Spot locked pages in page_referenced_one and treat them as referenced.
Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Tested-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ethan Solomita <solo@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9eccf2a8
...@@ -283,7 +283,10 @@ static int page_referenced_one(struct page *page, ...@@ -283,7 +283,10 @@ static int page_referenced_one(struct page *page,
if (!pte) if (!pte)
goto out; goto out;
if (ptep_clear_flush_young(vma, address, pte)) if (vma->vm_flags & VM_LOCKED) {
referenced++;
*mapcount = 1; /* break early from loop */
} else if (ptep_clear_flush_young(vma, address, pte))
referenced++; referenced++;
/* Pretend the page is referenced if the task has the /* Pretend the page is referenced if the task has the
......
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