diff --git a/Documentation/workqueue.txt b/Documentation/workqueue.txt
index e4498a2872c37a0b3b156ddc7ad7135d030d224d..996a27d9b8db8414da1751d92083dd11e91cff01 100644
--- a/Documentation/workqueue.txt
+++ b/Documentation/workqueue.txt
@@ -196,11 +196,11 @@ resources, scheduled and executed.
suspend operations. Work items on the wq are drained and no
new work item starts execution until thawed.
- WQ_RESCUER
+ WQ_MEM_RECLAIM
All wq which might be used in the memory reclaim paths _MUST_
- have this flag set. This reserves one worker exclusively for
- the execution of this wq under memory pressure.
+ have this flag set. The wq is guaranteed to have at least one
+ execution context regardless of memory pressure.
WQ_HIGHPRI
@@ -356,11 +356,11 @@ If q1 has WQ_CPU_INTENSIVE set,
6. Guidelines
-* Do not forget to use WQ_RESCUER if a wq may process work items which
- are used during memory reclaim. Each wq with WQ_RESCUER set has one
- rescuer thread reserved for it. If there is dependency among
- multiple work items used during memory reclaim, they should be
- queued to separate wq each with WQ_RESCUER.
+* Do not forget to use WQ_MEM_RECLAIM if a wq may process work items
+ which are used during memory reclaim. Each wq with WQ_MEM_RECLAIM
+ set has an execution context reserved for it. If there is
+ dependency among multiple work items used during memory reclaim,
+ they should be queued to separate wq each with WQ_MEM_RECLAIM.
* Unless strict ordering is required, there is no need to use ST wq.
@@ -368,12 +368,13 @@ If q1 has WQ_CPU_INTENSIVE set,
recommended. In most use cases, concurrency level usually stays
well under the default limit.
-* A wq serves as a domain for forward progress guarantee (WQ_RESCUER),
- flush and work item attributes. Work items which are not involved
- in memory reclaim and don't need to be flushed as a part of a group
- of work items, and don't require any special attribute, can use one
- of the system wq. There is no difference in execution
- characteristics between using a dedicated wq and a system wq.
+* A wq serves as a domain for forward progress guarantee
+ (WQ_MEM_RECLAIM, flush and work item attributes. Work items which
+ are not involved in memory reclaim and don't need to be flushed as a
+ part of a group of work items, and don't require any special
+ attribute, can use one of the system wq. There is no difference in
+ execution characteristics between using a dedicated wq and a system
+ wq.
* Unless work items are expected to consume a huge amount of CPU
cycles, using a bound wq is usually beneficial due to the increased
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index e30c537cce32f99ab7fcb07f7f124cd920c4cd4b..f5296bb19ec0a58fba1a58054d645576d5fe3e4e 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -3335,7 +3335,7 @@ void ata_sff_port_init(struct ata_port *ap)
int __init ata_sff_init(void)
{
- ata_sff_wq = alloc_workqueue("ata_sff", WQ_RESCUER, WQ_MAX_ACTIVE);
+ ata_sff_wq = alloc_workqueue("ata_sff", WQ_MEM_RECLAIM, WQ_MAX_ACTIVE);
if (!ata_sff_wq)
return -ENOMEM;
diff --git a/fs/gfs2/main.c b/fs/gfs2/main.c
index b1e9630eb46a8d0338fef57ffa15caf23ab1cf0f..1c5f46075d52f3cb7c9b8d5741afc01e57ba58de 100644
--- a/fs/gfs2/main.c
+++ b/fs/gfs2/main.c
@@ -140,7 +140,7 @@ static int __init init_gfs2_fs(void)
error = -ENOMEM;
gfs_recovery_wq = alloc_workqueue("gfs_recovery",
- WQ_NON_REENTRANT | WQ_RESCUER, 0);
+ WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
if (!gfs_recovery_wq)
goto fail_wq;
diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 286e36e21dae587672216d7b7722488e91b45758..6838aefca71f2428799420026704b85f30636fa4 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -1933,7 +1933,7 @@ xfs_buf_init(void)
goto out;
xfslogd_workqueue = alloc_workqueue("xfslogd",
- WQ_RESCUER | WQ_HIGHPRI, 1);
+ WQ_MEM_RECLAIM | WQ_HIGHPRI, 1);
if (!xfslogd_workqueue)
goto out_free_buf_zone;
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index e33ff4a917031f699908698a1d378825557f0775..03bbe903e5ced4b0af5d5858a9c3b4685731181a 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -243,11 +243,12 @@ enum {
WQ_NON_REENTRANT = 1 << 0, /* guarantee non-reentrance */
WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
WQ_FREEZEABLE = 1 << 2, /* freeze during suspend */
- WQ_RESCUER = 1 << 3, /* has an rescue worker */
+ WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
WQ_HIGHPRI = 1 << 4, /* high priority */
WQ_CPU_INTENSIVE = 1 << 5, /* cpu instensive workqueue */
WQ_DYING = 1 << 6, /* internal: workqueue is dying */
+ WQ_RESCUER = 1 << 7, /* internal: workqueue has rescuer */
WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
@@ -309,7 +310,7 @@ __alloc_workqueue_key(const char *name, unsigned int flags, int max_active,
/**
* alloc_ordered_workqueue - allocate an ordered workqueue
* @name: name of the workqueue
- * @flags: WQ_* flags (only WQ_FREEZEABLE and WQ_RESCUER are meaningful)
+ * @flags: WQ_* flags (only WQ_FREEZEABLE and WQ_MEM_RECLAIM are meaningful)
*
* Allocate an ordered workqueue. An ordered workqueue executes at
* most one work item at any given time in the queued order. They are
@@ -325,11 +326,11 @@ alloc_ordered_workqueue(const char *name, unsigned int flags)
}
#define create_workqueue(name) \
- alloc_workqueue((name), WQ_RESCUER, 1)
+ alloc_workqueue((name), WQ_MEM_RECLAIM, 1)
#define create_freezeable_workqueue(name) \
- alloc_workqueue((name), WQ_FREEZEABLE | WQ_UNBOUND | WQ_RESCUER, 1)
+ alloc_workqueue((name), WQ_FREEZEABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
#define create_singlethread_workqueue(name) \
- alloc_workqueue((name), WQ_UNBOUND | WQ_RESCUER, 1)
+ alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
extern void destroy_workqueue(struct workqueue_struct *wq);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b57a8babdec35bce4a4435ef6414224e76e412c2..2c6871cbcbeedbbd4afa06cba941e7aeb066e905 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2847,6 +2847,13 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name,
struct workqueue_struct *wq;
unsigned int cpu;
+ /*
+ * Workqueues which may be used during memory reclaim should
+ * have a rescuer to guarantee forward progress.
+ */
+ if (flags & WQ_MEM_RECLAIM)
+ flags |= WQ_RESCUER;
+
/*
* Unbound workqueues aren't concurrency managed and should be
* dispatched to workers immediately.