---

yaml --- r: 356552 b: refs/heads/master c: 21caf2f h: refs/heads/master v: v3
git-mirror · Feb 24, 2013 · d8e8b8c · d8e8b8c
1 parent 40b6879
commit d8e8b8c
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Showing 4 changed files with 33 additions and 4 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 258401a60c4df39332f30ef57afbc6dbf29a7e84
+refs/heads/master: 21caf2fc1931b485483ddd254b634fa8f0099963
diff --git a/trunk/include/linux/sched.h b/trunk/include/linux/sched.h
@@ -51,6 +51,7 @@ struct sched_param {
 #include <linux/cred.h>
 #include <linux/llist.h>
 #include <linux/uidgid.h>
+#include <linux/gfp.h>
 
 #include <asm/processor.h>
 
@@ -1791,6 +1792,7 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut,
 #define PF_FROZEN	0x00010000	/* frozen for system suspend */
 #define PF_FSTRANS	0x00020000	/* inside a filesystem transaction */
 #define PF_KSWAPD	0x00040000	/* I am kswapd */
+#define PF_MEMALLOC_NOIO 0x00080000	/* Allocating memory without IO involved */
 #define PF_LESS_THROTTLE 0x00100000	/* Throttle me less: I clean memory */
 #define PF_KTHREAD	0x00200000	/* I am a kernel thread */
 #define PF_RANDOMIZE	0x00400000	/* randomize virtual address space */
@@ -1828,6 +1830,26 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut,
 #define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
 #define used_math() tsk_used_math(current)
 
+/* __GFP_IO isn't allowed if PF_MEMALLOC_NOIO is set in current->flags */
+static inline gfp_t memalloc_noio_flags(gfp_t flags)
+{
+	if (unlikely(current->flags & PF_MEMALLOC_NOIO))
+		flags &= ~__GFP_IO;
+	return flags;
+}
+
+static inline unsigned int memalloc_noio_save(void)
+{
+	unsigned int flags = current->flags & PF_MEMALLOC_NOIO;
+	current->flags |= PF_MEMALLOC_NOIO;
+	return flags;
+}
+
+static inline void memalloc_noio_restore(unsigned int flags)
+{
+	current->flags = (current->flags & ~PF_MEMALLOC_NOIO) | flags;
+}
+
 /*
  * task->jobctl flags
  */

diff --git a/trunk/mm/page_alloc.c b/trunk/mm/page_alloc.c
@@ -2624,10 +2624,17 @@ __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
 	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
 			zonelist, high_zoneidx, alloc_flags,
 			preferred_zone, migratetype);
-	if (unlikely(!page))
+	if (unlikely(!page)) {
+		/*
+		 * Runtime PM, block IO and its error handling path
+		 * can deadlock because I/O on the device might not
+		 * complete.
+		 */
+		gfp_mask = memalloc_noio_flags(gfp_mask);
 		page = __alloc_pages_slowpath(gfp_mask, order,
 				zonelist, high_zoneidx, nodemask,
 				preferred_zone, migratetype);
+	}
 
 	trace_mm_page_alloc(page, order, gfp_mask, migratetype);
 

diff --git a/trunk/mm/vmscan.c b/trunk/mm/vmscan.c
@@ -2352,7 +2352,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 {
 	unsigned long nr_reclaimed;
 	struct scan_control sc = {
-		.gfp_mask = gfp_mask,
+		.gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)),
 		.may_writepage = !laptop_mode,
 		.nr_to_reclaim = SWAP_CLUSTER_MAX,
 		.may_unmap = 1,
@@ -3313,7 +3313,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 		.may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
 		.may_swap = 1,
 		.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
-		.gfp_mask = gfp_mask,
+		.gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)),
 		.order = order,
 		.priority = ZONE_RECLAIM_PRIORITY,
 	};