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Commit 89e9b9e0 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
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writeback: add {CONFIG|BDI_CAP|FS}_CGROUP_WRITEBACK 



cgroup writeback requires support from both bdi and filesystem sides.
Add BDI_CAP_CGROUP_WRITEBACK and FS_CGROUP_WRITEBACK to indicate
support and enable BDI_CAP_CGROUP_WRITEBACK on block based bdi's by
default.  Also, define CONFIG_CGROUP_WRITEBACK which is enabled if
both MEMCG and BLK_CGROUP are enabled.

inode_cgwb_enabled() which determines whether a given inode's both bdi
and fs support cgroup writeback is added.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 4aa9c692

block/blk-core.c

+1 −1
Original line number Diff line number Diff line
@@ -621,7 +621,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) 


	q->backing_dev_info.ra_pages =

			(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;

	q->backing_dev_info.capabilities = 0;

	q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;

	q->backing_dev_info.name = "block";

	q->node = node_id;

include/linux/backing-dev.h

+31 −1
Original line number Diff line number Diff line
@@ -134,12 +134,15 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); 
 * BDI_CAP_NO_WRITEBACK:   Don't write pages back

 * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages

 * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.

 *

 * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback.

 */

#define BDI_CAP_NO_ACCT_DIRTY	0x00000001

#define BDI_CAP_NO_WRITEBACK	0x00000002

#define BDI_CAP_NO_ACCT_WB	0x00000004

#define BDI_CAP_STABLE_WRITES	0x00000008

#define BDI_CAP_STRICTLIMIT	0x00000010

#define BDI_CAP_CGROUP_WRITEBACK 0x00000020



#define BDI_CAP_NO_ACCT_AND_WRITEBACK \

	(BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
@@ -229,4 +232,31 @@ static inline int bdi_sched_wait(void *word) 
	return 0;

}



#ifdef CONFIG_CGROUP_WRITEBACK



/**

 * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode

 * @inode: inode of interest

 *

 * cgroup writeback requires support from both the bdi and filesystem.

 * Test whether @inode has both.

 */

static inline bool inode_cgwb_enabled(struct inode *inode)

{

	struct backing_dev_info *bdi = inode_to_bdi(inode);



	return bdi_cap_account_dirty(bdi) &&

		(bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&

		(inode->i_sb->s_type->fs_flags & FS_CGROUP_WRITEBACK);

}



#else	/* CONFIG_CGROUP_WRITEBACK */



static inline bool inode_cgwb_enabled(struct inode *inode)

{

	return false;

}



#endif	/* CONFIG_CGROUP_WRITEBACK */



#endif	/* _LINUX_BACKING_DEV_H */

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -1897,6 +1897,7 @@ struct file_system_type { 
#define FS_HAS_SUBTYPE		4

#define FS_USERNS_MOUNT		8	/* Can be mounted by userns root */

#define FS_USERNS_DEV_MOUNT	16 /* A userns mount does not imply MNT_NODEV */

#define FS_CGROUP_WRITEBACK	32	/* Supports cgroup-aware writeback */

#define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move() during rename() internally. */

	struct dentry *(*mount) (struct file_system_type *, int,

		       const char *, void *);

init/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -1141,6 +1141,11 @@ config DEBUG_BLK_CGROUP 
	Enable some debugging help. Currently it exports additional stat

	files in a cgroup which can be useful for debugging.



config CGROUP_WRITEBACK

	bool

	depends on MEMCG && BLK_CGROUP

	default y



endif # CGROUPS



config CHECKPOINT_RESTORE