mm: introduce __GFP_MEMALLOC to allow access to emergency reserves
__GFP_MEMALLOC will allow the allocation to disregard the watermarks, much
like PF_MEMALLOC. It allows one to pass along the memalloc state in
object related allocation flags as opposed to task related flags, such as
sk->sk_allocation. This removes the need for ALLOC_PFMEMALLOC as callers
using __GFP_MEMALLOC can get the ALLOC_NO_WATERMARK flag which is now
enough to identify allocations related to page reclaim.
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Cc: David Miller <[email protected]>
Cc: Neil Brown <[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 38e5be6..8f65abe 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1513,7 +1513,6 @@
#define ALLOC_HARDER 0x10 /* try to alloc harder */
#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET 0x40 /* check for correct cpuset */
-#define ALLOC_PFMEMALLOC 0x80 /* Caller has PF_MEMALLOC set */
#ifdef CONFIG_FAIL_PAGE_ALLOC
@@ -2294,11 +2293,10 @@
} else if (unlikely(rt_task(current)) && !in_interrupt())
alloc_flags |= ALLOC_HARDER;
- if ((current->flags & PF_MEMALLOC) ||
- unlikely(test_thread_flag(TIF_MEMDIE))) {
- alloc_flags |= ALLOC_PFMEMALLOC;
-
- if (likely(!(gfp_mask & __GFP_NOMEMALLOC)) && !in_interrupt())
+ if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
+ if (gfp_mask & __GFP_MEMALLOC)
+ alloc_flags |= ALLOC_NO_WATERMARKS;
+ else if (likely(!(gfp_mask & __GFP_NOMEMALLOC)) && !in_interrupt())
alloc_flags |= ALLOC_NO_WATERMARKS;
}
@@ -2307,7 +2305,7 @@
bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
- return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_PFMEMALLOC);
+ return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
}
static inline struct page *
@@ -2498,12 +2496,12 @@
return page;
got_pg:
/*
- * page->pfmemalloc is set when the caller had PFMEMALLOC set or is
- * been OOM killed. 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 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_PFMEMALLOC);
+ page->pfmemalloc = !!(alloc_flags & ALLOC_NO_WATERMARKS);
if (kmemcheck_enabled)
kmemcheck_pagealloc_alloc(page, order, gfp_mask);
