Currently, majority of cgroup writeback support including all the
above functions are implemented in include/linux/backing-dev.h and
mm/backing-dev.c; however, the portion closely related to writeback
logic implemented in include/linux/writeback.h and mm/page-writeback.c
will expand to support foreign writeback detection and correction.
This patch moves wb[_try]_get() and wb_put() to
include/linux/backing-dev-defs.h so that they can be used from
writeback.h and inode_{attach|detach}_wb() to writeback.h and
page-writeback.c.
This is pure reorganization and doesn't introduce any functional
changes.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
---
fs/fs-writeback.c | 31 +++++++++++++++
include/linux/backing-dev-defs.h | 50 ++++++++++++++++++++++++
include/linux/backing-dev.h | 82 ----------------------------------------
include/linux/writeback.h | 46 ++++++++++++++++++++++
mm/backing-dev.c | 30 ---------------
5 files changed, 127 insertions(+), 112 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 683bd92..dfb7bb6 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -27,6 +27,7 @@
#include <linux/backing-dev.h>
#include <linux/tracepoint.h>
#include <linux/device.h>
+#include <linux/memcontrol.h>
#include "internal.h"
/*
@@ -200,6 +201,36 @@ static void wb_wait_for_completion(struct backing_dev_info *bdi,
#ifdef CONFIG_CGROUP_WRITEBACK
+void __inode_attach_wb(struct inode *inode, struct page *page)
+{
+ struct backing_dev_info *bdi = inode_to_bdi(inode);
+ struct bdi_writeback *wb = NULL;
+
+ if (inode_cgwb_enabled(inode)) {
+ struct cgroup_subsys_state *memcg_css;
+
+ if (page) {
+ memcg_css = mem_cgroup_css_from_page(page);
+ wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
+ } else {
+ /* must pin memcg_css, see wb_get_create() */
+ memcg_css = task_get_css(current, memory_cgrp_id);
+ wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
+ css_put(memcg_css);
+ }
+ }
+
+ if (!wb)
+ wb = &bdi->wb;
+
+ /*
+ * There may be multiple instances of this function racing to
+ * update the same inode. Use cmpxchg() to tell the winner.
+ */
+ if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
+ wb_put(wb);
+}
+
/**
* mapping_congested - test whether a mapping is congested for a task
* @mapping: address space to test for congestion
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index 8d470b7..e047b49 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -186,4 +186,54 @@ static inline void set_bdi_congested(struct backing_dev_info *bdi, int sync)
set_wb_congested(bdi->wb.congested, sync);
}
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+/**
+ * wb_tryget - try to increment a wb's refcount
+ * @wb: bdi_writeback to get
+ */
+static inline bool wb_tryget(struct bdi_writeback *wb)
+{
+ if (wb != &wb->bdi->wb)
+ return percpu_ref_tryget(&wb->refcnt);
+ return true;
+}
+
+/**
+ * wb_get - increment a wb's refcount
+ * @wb: bdi_writeback to get
+ */
+static inline void wb_get(struct bdi_writeback *wb)
+{
+ if (wb != &wb->bdi->wb)
+ percpu_ref_get(&wb->refcnt);
+}
+
+/**
+ * wb_put - decrement a wb's refcount
+ * @wb: bdi_writeback to put
+ */
+static inline void wb_put(struct bdi_writeback *wb)
+{
+ if (wb != &wb->bdi->wb)
+ percpu_ref_put(&wb->refcnt);
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static inline bool wb_tryget(struct bdi_writeback *wb)
+{
+ return true;
+}
+
+static inline void wb_get(struct bdi_writeback *wb)
+{
+}
+
+static inline void wb_put(struct bdi_writeback *wb)
+{
+}
+
+#endif /* CONFIG_CGROUP_WRITEBACK */
+
#endif /* __LINUX_BACKING_DEV_DEFS_H */
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index a9a843c..119f0af 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -243,7 +243,6 @@ void wb_congested_put(struct bdi_writeback_congested *congested);
struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
struct cgroup_subsys_state *memcg_css,
gfp_t gfp);
-void __inode_attach_wb(struct inode *inode, struct page *page);
void wb_memcg_offline(struct mem_cgroup *memcg);
void wb_blkcg_offline(struct blkcg *blkcg);
int mapping_congested(struct address_space *mapping, struct task_struct *task,
@@ -266,37 +265,6 @@ static inline bool inode_cgwb_enabled(struct inode *inode)
}
/**
- * wb_tryget - try to increment a wb's refcount
- * @wb: bdi_writeback to get
- */
-static inline bool wb_tryget(struct bdi_writeback *wb)
-{
- if (wb != &wb->bdi->wb)
- return percpu_ref_tryget(&wb->refcnt);
- return true;
-}
-
-/**
- * wb_get - increment a wb's refcount
- * @wb: bdi_writeback to get
- */
-static inline void wb_get(struct bdi_writeback *wb)
-{
- if (wb != &wb->bdi->wb)
- percpu_ref_get(&wb->refcnt);
-}
-
-/**
- * wb_put - decrement a wb's refcount
- * @wb: bdi_writeback to put
- */
-static inline void wb_put(struct bdi_writeback *wb)
-{
- if (wb != &wb->bdi->wb)
- percpu_ref_put(&wb->refcnt);
-}
-
-/**
* wb_find_current - find wb for %current on a bdi
* @bdi: bdi of interest
*
@@ -355,35 +323,6 @@ wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
}
/**
- * inode_attach_wb - associate an inode with its wb
- * @inode: inode of interest
- * @page: page being dirtied (may be NULL)
- *
- * If @inode doesn't have its wb, associate it with the wb matching the
- * memcg of @page or, if @page is NULL, %current. May be called w/ or w/o
- * @inode->i_lock.
- */
-static inline void inode_attach_wb(struct inode *inode, struct page *page)
-{
- if (!inode->i_wb)
- __inode_attach_wb(inode, page);
-}
-
-/**
- * inode_detach_wb - disassociate an inode from its wb
- * @inode: inode of interest
- *
- * @inode is being freed. Detach from its wb.
- */
-static inline void inode_detach_wb(struct inode *inode)
-{
- if (inode->i_wb) {
- wb_put(inode->i_wb);
- inode->i_wb = NULL;
- }
-}
-
-/**
* inode_to_wb - determine the wb of an inode
* @inode: inode of interest
*
@@ -472,19 +411,6 @@ static inline void wb_congested_put(struct bdi_writeback_congested *congested)
{
}
-static inline bool wb_tryget(struct bdi_writeback *wb)
-{
- return true;
-}
-
-static inline void wb_get(struct bdi_writeback *wb)
-{
-}
-
-static inline void wb_put(struct bdi_writeback *wb)
-{
-}
-
static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
{
return &bdi->wb;
@@ -496,14 +422,6 @@ wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
return &bdi->wb;
}
-static inline void inode_attach_wb(struct inode *inode, struct page *page)
-{
-}
-
-static inline void inode_detach_wb(struct inode *inode)
-{
-}
-
static inline struct bdi_writeback *inode_to_wb(struct inode *inode)
{
return &inode_to_bdi(inode)->wb;
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 9ae0648..23ada53 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -8,6 +8,7 @@
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/flex_proportions.h>
+#include <linux/backing-dev-defs.h>
DECLARE_PER_CPU(int, dirty_throttle_leaks);
@@ -173,6 +174,51 @@ static inline void wait_on_inode(struct inode *inode)
wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE);
}
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+void __inode_attach_wb(struct inode *inode, struct page *page);
+
+/**
+ * inode_attach_wb - associate an inode with its wb
+ * @inode: inode of interest
+ * @page: page being dirtied (may be NULL)
+ *
+ * If @inode doesn't have its wb, associate it with the wb matching the
+ * memcg of @page or, if @page is NULL, %current. May be called w/ or w/o
+ * @inode->i_lock.
+ */
+static inline void inode_attach_wb(struct inode *inode, struct page *page)
+{
+ if (!inode->i_wb)
+ __inode_attach_wb(inode, page);
+}
+
+/**
+ * inode_detach_wb - disassociate an inode from its wb
+ * @inode: inode of interest
+ *
+ * @inode is being freed. Detach from its wb.
+ */
+static inline void inode_detach_wb(struct inode *inode)
+{
+ if (inode->i_wb) {
+ wb_put(inode->i_wb);
+ inode->i_wb = NULL;
+ }
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static inline void inode_attach_wb(struct inode *inode, struct page *page)
+{
+}
+
+static inline void inode_detach_wb(struct inode *inode)
+{
+}
+
+#endif /* CONFIG_CGROUP_WRITEBACK */
+
/*
* mm/page-writeback.c
*/
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8828edf..ecfc31f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -661,36 +661,6 @@ struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
return wb;
}
-void __inode_attach_wb(struct inode *inode, struct page *page)
-{
- struct backing_dev_info *bdi = inode_to_bdi(inode);
- struct bdi_writeback *wb = NULL;
-
- if (inode_cgwb_enabled(inode)) {
- struct cgroup_subsys_state *memcg_css;
-
- if (page) {
- memcg_css = mem_cgroup_css_from_page(page);
- wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
- } else {
- /* must pin memcg_css, see wb_get_create() */
- memcg_css = task_get_css(current, memory_cgrp_id);
- wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
- css_put(memcg_css);
- }
- }
-
- if (!wb)
- wb = &bdi->wb;
-
- /*
- * There may be multiple instances of this function racing to
- * update the same inode. Use cmpxchg() to tell the winner.
- */
- if (unlikely(cmpxchg(&inode->i_wb, NULL, wb)))
- wb_put(wb);
-}
-
static void cgwb_bdi_init(struct backing_dev_info *bdi)
{
bdi->wb.memcg_css = mem_cgroup_root_css;
--
2.1.0
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