[PATCH] mm: gfp_atomic comments
Clarify in comments that GFP_ATOMIC means both "don't sleep" and "use
emergency pools", hence both ALLOC_HARDER and ALLOC_HIGH.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 8b2eab9..da7ce87 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -57,6 +57,7 @@
__GFP_NOFAIL|__GFP_NORETRY|__GFP_NO_GROW|__GFP_COMP| \
__GFP_NOMEMALLOC|__GFP_HARDWALL)
+/* GFP_ATOMIC means both !wait (__GFP_WAIT not set) and use emergency pool */
#define GFP_ATOMIC (__GFP_HIGH)
#define GFP_NOIO (__GFP_WAIT)
#define GFP_NOFS (__GFP_WAIT | __GFP_IO)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ce991b1..d41a066 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -931,7 +931,8 @@
*
* The caller may dip into page reserves a bit more if the caller
* cannot run direct reclaim, or if the caller has realtime scheduling
- * policy.
+ * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
+ * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
*/
alloc_flags = ALLOC_WMARK_MIN;
if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
