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xfs: convert inode shrinker to per-filesystem contexts

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Now the shrinker passes us a context, wire up a shrinker context per
filesystem. This allows us to remove the global mount list and the
locking problems that introduced. It also means that a shrinker call
does not need to traverse clean filesystems before finding a
filesystem with reclaimable inodes.  This significantly reduces
scanning overhead when lots of filesystems are present.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Dave Chinner 2010-07-20 08:07:02 +10:00 • committed by Dave Chinner
commit 70e60ce715
4 changed files with 15 additions and 53 deletions
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2
fs/xfs/linux-2.6/xfs_super.c
View file

@ -1883,7 +1883,6 @@ init_xfs_fs(void)
goto out_cleanup_procfs;
vfs_initquota();
xfs_inode_shrinker_init();
error = register_filesystem(&xfs_fs_type);
if (error)
@ -1911,7 +1910,6 @@ exit_xfs_fs(void)
{
vfs_exitquota();
unregister_filesystem(&xfs_fs_type);
xfs_inode_shrinker_destroy();
xfs_sysctl_unregister();
xfs_cleanup_procfs();
xfs_buf_terminate();

62
fs/xfs/linux-2.6/xfs_sync.c
View file

@ -828,14 +828,7 @@ xfs_reclaim_inodes(
/*
* Shrinker infrastructure.
*
* This is all far more complex than it needs to be. It adds a global list of
* mounts because the shrinkers can only call a global context. We need to make
* the shrinkers pass a context to avoid the need for global state.
*/
static LIST_HEAD(xfs_mount_list);
static struct rw_semaphore xfs_mount_list_lock;
static int
xfs_reclaim_inode_shrink(
struct shrinker *shrink,
@ -847,65 +840,38 @@ xfs_reclaim_inode_shrink(
xfs_agnumber_t ag;
int reclaimable = 0;
mp = container_of(shrink, struct xfs_mount, m_inode_shrink);
if (nr_to_scan) {
if (!(gfp_mask & __GFP_FS))
return -1;
down_read(&xfs_mount_list_lock);
list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
XFS_ICI_RECLAIM_TAG, 1, &nr_to_scan);
if (nr_to_scan <= 0)
break;
}
up_read(&xfs_mount_list_lock);
}
/* if we don't exhaust the scan, don't bother coming back */
if (nr_to_scan > 0)
return -1;
}
down_read(&xfs_mount_list_lock);
list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
pag = xfs_perag_get(mp, ag);
reclaimable += pag->pag_ici_reclaimable;
xfs_perag_put(pag);
}
for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
pag = xfs_perag_get(mp, ag);
reclaimable += pag->pag_ici_reclaimable;
xfs_perag_put(pag);
}
up_read(&xfs_mount_list_lock);
return reclaimable;
}
static struct shrinker xfs_inode_shrinker = {
.shrink = xfs_reclaim_inode_shrink,
.seeks = DEFAULT_SEEKS,
};
void __init
xfs_inode_shrinker_init(void)
{
init_rwsem(&xfs_mount_list_lock);
register_shrinker(&xfs_inode_shrinker);
}
void
xfs_inode_shrinker_destroy(void)
{
ASSERT(list_empty(&xfs_mount_list));
unregister_shrinker(&xfs_inode_shrinker);
}
void
xfs_inode_shrinker_register(
struct xfs_mount *mp)
{
down_write(&xfs_mount_list_lock);
list_add_tail(&mp->m_mplist, &xfs_mount_list);
up_write(&xfs_mount_list_lock);
mp->m_inode_shrink.shrink = xfs_reclaim_inode_shrink;
mp->m_inode_shrink.seeks = DEFAULT_SEEKS;
register_shrinker(&mp->m_inode_shrink);
}
void
xfs_inode_shrinker_unregister(
struct xfs_mount *mp)
{
down_write(&xfs_mount_list_lock);
list_del(&mp->m_mplist);
up_write(&xfs_mount_list_lock);
unregister_shrinker(&mp->m_inode_shrink);
}

2
fs/xfs/linux-2.6/xfs_sync.h
View file

@ -55,8 +55,6 @@ int xfs_inode_ag_iterator(struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, struct xfs_perag *pag, int flags),
int flags, int tag, int write_lock, int *nr_to_scan);
void xfs_inode_shrinker_init(void);
void xfs_inode_shrinker_destroy(void);
void xfs_inode_shrinker_register(struct xfs_mount *mp);
void xfs_inode_shrinker_unregister(struct xfs_mount *mp);

2
fs/xfs/xfs_mount.h
View file

@ -259,7 +259,7 @@ typedef struct xfs_mount {
wait_queue_head_t m_wait_single_sync_task;
__int64_t m_update_flags; /* sb flags we need to update
on the next remount,rw */
struct list_head m_mplist; /* inode shrinker mount list */
struct shrinker m_inode_shrink; /* inode reclaim shrinker */
} xfs_mount_t;
/*