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writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()

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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@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-05-28 14:50:49 -04:00 committed by Jens Axboe
parent 97c9341f72
commit 21c6321fbb
5 changed files with 127 additions and 112 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
fs/fs-writeback.c
View File

@ -27,6 +27,7 @@
#include <linux/backing-dev.h>
#include <linux/tracepoint.h>
#include <linux/device.h>
#include <linux/memcontrol.h>
#include "internal.h"
/*
@ -213,6 +214,36 @@ 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);
}
/**
* inode_congested - test whether an inode is congested
* @inode: inode to test for congestion

50
include/linux/backing-dev-defs.h
View File

@ -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 */

82
include/linux/backing-dev.h
View File

@ -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 inode_congested(struct inode *inode, int cong_bits);
@ -264,37 +263,6 @@ static inline bool inode_cgwb_enabled(struct inode *inode)
(inode->i_sb->s_type->fs_flags & FS_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);
}
/**
* wb_find_current - find wb for %current on a bdi
* @bdi: bdi of interest
@ -353,35 +321,6 @@ wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp)
return wb;
}
/**
* 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
@ -471,19 +410,6 @@ 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;
@ -495,14 +421,6 @@ 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;

46
include/linux/writeback.h
View File

@ -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
*/

30
mm/backing-dev.c
View File

@ -660,36 +660,6 @@ 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;