From: Peter Zijlstra <[email protected]>
__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.
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Suresh Jayaraman <[email protected]>
---
include/linux/gfp.h | 3 ++-
mm/page_alloc.c | 4 +++-
2 files changed, 5 insertions(+), 2 deletions(-)
Index: mmotm/include/linux/gfp.h
===================================================================
--- mmotm.orig/include/linux/gfp.h
+++ mmotm/include/linux/gfp.h
@@ -46,6 +46,7 @@ struct vm_area_struct;
#define __GFP_REPEAT ((__force gfp_t)0x400u) /* See above */
#define __GFP_NOFAIL ((__force gfp_t)0x800u) /* See above */
#define __GFP_NORETRY ((__force gfp_t)0x1000u)/* See above */
+#define __GFP_MEMALLOC ((__force gfp_t)0x2000u)/* Use emergency reserves */
#define __GFP_COMP ((__force gfp_t)0x4000u)/* Add compound page metadata */
#define __GFP_ZERO ((__force gfp_t)0x8000u)/* Return zeroed page on success */
#define __GFP_NOMEMALLOC ((__force gfp_t)0x10000u) /* Don't use emergency reserves */
@@ -96,7 +97,7 @@ 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)
Index: mmotm/mm/page_alloc.c
===================================================================
--- mmotm.orig/mm/page_alloc.c
+++ mmotm/mm/page_alloc.c
@@ -1710,7 +1710,9 @@ int gfp_to_alloc_flags(gfp_t gfp_mask)
alloc_flags |= ALLOC_HARDER;
if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
- if (!in_irq() && (p->flags & PF_MEMALLOC))
+ if (gfp_mask & __GFP_MEMALLOC)
+ alloc_flags |= ALLOC_NO_WATERMARKS;
+ else if (!in_irq() && (p->flags & PF_MEMALLOC))
alloc_flags |= ALLOC_NO_WATERMARKS;
else if (!in_interrupt() &&
unlikely(test_thread_flag(TIF_MEMDIE)))