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authorJan Kara <jack@suse.cz>2017-08-07 13:19:50 +0200
committerJan Kara <jack@suse.cz>2017-08-17 22:07:59 +0200
commit7b9ca4c61bc278b771fb57d6290a31ab1fc7fdac (patch)
tree3e9c7464525efa2a9dd50d02e7fe8f7df45a4961 /include/linux/quota.h
parentf4a8116a4c8c8f754d0ec1498a2ba4b63d114e6a (diff)
quota: Reduce contention on dq_data_lock
dq_data_lock is currently used to protect all modifications of quota accounting information, consistency of quota accounting on the inode, and dquot pointers from inode. As a result contention on the lock can be pretty heavy. Reduce the contention on the lock by protecting quota accounting information by a new dquot->dq_dqb_lock and consistency of quota accounting with inode usage by inode->i_lock. This change reduces time to create 500000 files on ext4 on ramdisk by 50 different processes in separate directories by 6% when user quota is turned on. When those 50 processes belong to 50 different users, the improvement is about 9%. Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'include/linux/quota.h')
-rw-r--r--include/linux/quota.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/quota.h b/include/linux/quota.h
index eccc1cb6274e..074123975595 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -298,12 +298,13 @@ struct dquot {
struct list_head dq_free; /* Free list element */
struct list_head dq_dirty; /* List of dirty dquots */
struct mutex dq_lock; /* dquot IO lock */
+ spinlock_t dq_dqb_lock; /* Lock protecting dq_dqb changes */
atomic_t dq_count; /* Use count */
struct super_block *dq_sb; /* superblock this applies to */
struct kqid dq_id; /* ID this applies to (uid, gid, projid) */
loff_t dq_off; /* Offset of dquot on disk */
unsigned long dq_flags; /* See DQ_* */
- struct mem_dqblk dq_dqb; /* Diskquota usage */
+ struct mem_dqblk dq_dqb; /* Diskquota usage [dq_dqb_lock] */
};
/* Operations which must be implemented by each quota format */