mm: only set page->pfmemalloc when ALLOC_NO_WATERMARKS was used
__alloc_pages_slowpath() is called when the number of free pages is below
the low watermark. If the caller is entitled to use ALLOC_NO_WATERMARKS
then the page will be marked page->pfmemalloc. This protects more pages
than are strictly necessary as we only need to protect pages allocated
below the min watermark (the pfmemalloc reserves).
This patch only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was
required to allocate the page.
[[email protected]: David noticed the problem during review]
Signed-off-by: Mel Gorman <[email protected]>
Cc: David Miller <[email protected]>
Cc: Neil Brown <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Mike Christie <[email protected]>
Cc: Eric B Munson <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Christoph Lameter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cd5390f..f9d9254 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2116,8 +2116,8 @@
page = get_page_from_freelist(gfp_mask, nodemask,
order, zonelist, high_zoneidx,
- alloc_flags, preferred_zone,
- migratetype);
+ alloc_flags & ~ALLOC_NO_WATERMARKS,
+ preferred_zone, migratetype);
if (page) {
preferred_zone->compact_considered = 0;
preferred_zone->compact_defer_shift = 0;
@@ -2209,8 +2209,8 @@
retry:
page = get_page_from_freelist(gfp_mask, nodemask, order,
zonelist, high_zoneidx,
- alloc_flags, preferred_zone,
- migratetype);
+ alloc_flags & ~ALLOC_NO_WATERMARKS,
+ preferred_zone, migratetype);
/*
* If an allocation failed after direct reclaim, it could be because
@@ -2381,8 +2381,17 @@
page = __alloc_pages_high_priority(gfp_mask, order,
zonelist, high_zoneidx, nodemask,
preferred_zone, migratetype);
- if (page)
+ if (page) {
+ /*
+ * page->pfmemalloc is set when ALLOC_NO_WATERMARKS was
+ * necessary to allocate the page. The expectation is
+ * that the caller is taking steps that will free more
+ * memory. The caller should avoid the page being used
+ * for !PFMEMALLOC purposes.
+ */
+ page->pfmemalloc = true;
goto got_pg;
+ }
}
/* Atomic allocations - we can't balance anything */
@@ -2499,14 +2508,6 @@
warn_alloc_failed(gfp_mask, order, NULL);
return page;
got_pg:
- /*
- * page->pfmemalloc is set when the caller had PFMEMALLOC set, is
- * been OOM killed or specified __GFP_MEMALLOC. The expectation is
- * that the caller is taking steps that will free more memory. The
- * caller should avoid the page being used for !PFMEMALLOC purposes.
- */
- page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
-
if (kmemcheck_enabled)
kmemcheck_pagealloc_alloc(page, order, gfp_mask);
