[PATCH 03/14] mm: Introduce __GFP_MEMALLOC to allow access to emergency reserves
From: Mel Gorman
Date: Thu Oct 06 2011 - 08:44:55 EST
__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 <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
include/linux/gfp.h | 10 ++++++++--
include/linux/mm_types.h | 2 +-
include/trace/events/gfpflags.h | 1 +
mm/page_alloc.c | 14 ++++++--------
mm/slab.c | 2 +-
5 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 3a76faf..38acdc7 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -23,6 +23,7 @@ struct vm_area_struct;
#define ___GFP_REPEAT 0x400u
#define ___GFP_NOFAIL 0x800u
#define ___GFP_NORETRY 0x1000u
+#define ___GFP_MEMALLOC 0x2000u
#define ___GFP_COMP 0x4000u
#define ___GFP_ZERO 0x8000u
#define ___GFP_NOMEMALLOC 0x10000u
@@ -75,9 +76,14 @@ struct vm_area_struct;
#define __GFP_REPEAT ((__force gfp_t)___GFP_REPEAT) /* See above */
#define __GFP_NOFAIL ((__force gfp_t)___GFP_NOFAIL) /* See above */
#define __GFP_NORETRY ((__force gfp_t)___GFP_NORETRY) /* See above */
+#define __GFP_MEMALLOC ((__force gfp_t)___GFP_MEMALLOC)/* Allow access to emergency reserves */
#define __GFP_COMP ((__force gfp_t)___GFP_COMP) /* Add compound page metadata */
#define __GFP_ZERO ((__force gfp_t)___GFP_ZERO) /* Return zeroed page on success */
-#define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC) /* Don't use emergency reserves */
+#define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC) /* Don't use emergency reserves.
+ * This takes precedence over the
+ * __GFP_MEMALLOC flag if both are
+ * set
+ */
#define __GFP_HARDWALL ((__force gfp_t)___GFP_HARDWALL) /* Enforce hardwall cpuset memory allocs */
#define __GFP_THISNODE ((__force gfp_t)___GFP_THISNODE)/* No fallback, no policies */
#define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE) /* Page is reclaimable */
@@ -127,7 +133,7 @@ struct vm_area_struct;
/* Control page allocator reclaim behavior */
#define GFP_RECLAIM_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS|\
__GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\
- __GFP_NORETRY|__GFP_NOMEMALLOC)
+ __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC)
/* Control slab gfp mask during early boot */
#define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_WAIT|__GFP_IO|__GFP_FS))
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3716e9f..0be3d43 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -54,7 +54,7 @@ struct page {
pgoff_t index; /* Our offset within mapping. */
void *freelist; /* slub first free object */
bool pfmemalloc; /* If set by the page allocator,
- * ALLOC_PFMEMALLOC was set
+ * ALLOC_NO_WATERMARKS was set
* and the low watermark was not
* met implying that the system
* is under some pressure. The
diff --git a/include/trace/events/gfpflags.h b/include/trace/events/gfpflags.h
index 9fe3a366..d6fd8e5 100644
--- a/include/trace/events/gfpflags.h
+++ b/include/trace/events/gfpflags.h
@@ -30,6 +30,7 @@
{(unsigned long)__GFP_COMP, "GFP_COMP"}, \
{(unsigned long)__GFP_ZERO, "GFP_ZERO"}, \
{(unsigned long)__GFP_NOMEMALLOC, "GFP_NOMEMALLOC"}, \
+ {(unsigned long)__GFP_MEMALLOC, "GFP_MEMALLOC"}, \
{(unsigned long)__GFP_HARDWALL, "GFP_HARDWALL"}, \
{(unsigned long)__GFP_THISNODE, "GFP_THISNODE"}, \
{(unsigned long)__GFP_RECLAIMABLE, "GFP_RECLAIMABLE"}, \
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 561cb61..03fd18c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1369,7 +1369,6 @@ failed:
#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
@@ -2058,11 +2057,10 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
} 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;
}
@@ -2071,7 +2069,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
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 *
@@ -2253,7 +2251,7 @@ got_pg:
* 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);
return page;
}
diff --git a/mm/slab.c b/mm/slab.c
index 1dd03e0..25f69ec 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3031,7 +3031,7 @@ static int cache_grow(struct kmem_cache *cachep,
if (!slabp)
goto opps1;
- /* Record if ALLOC_PFMEMALLOC was set when allocating the slab */
+ /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
if (pfmemalloc) {
struct array_cache *ac = cpu_cache_get(cachep);
slabp->pfmemalloc = true;
--
1.7.3.4
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