[PATCH 5/5] xfs: make use of new shrinker callout

Dave Chinner
2010-05-25T08:51:10Z

From: Dave Chinner <dchinner@redhat.com>

Convert the inode reclaim shrinker to use the new per-sb shrinker
operations. This fixes a bunch of lockdep warnings about the
xfs_mount_list_lock being taken in different reclaim contexts by
removing it, and allows the reclaim to be proportioned across
filesystems with no extra code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/linux-2.6/xfs_super.c | 23 ++++++--
fs/xfs/linux-2.6/xfs_sync.c | 124 +++++++++++-----------------------------
fs/xfs/linux-2.6/xfs_sync.h | 16 +++--
fs/xfs/quota/xfs_qm_syscalls.c | 2 +-
fs/xfs/xfs_mount.h | 1 -
5 files changed, 61 insertions(+), 105 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index f24dbe5..b59886a 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -1212,7 +1212,6 @@ xfs_fs_put_super(

xfs_unmountfs(mp);
xfs_freesb(mp);
- xfs_inode_shrinker_unregister(mp);
xfs_icsb_destroy_counters(mp);
xfs_close_devices(mp);
xfs_dmops_put(mp);
@@ -1626,8 +1625,6 @@ xfs_fs_fill_super(
if (error)
goto fail_vnrele;

- xfs_inode_shrinker_register(mp);
-
kfree(mtpt);
return 0;

@@ -1681,6 +1678,22 @@ xfs_fs_get_sb(
mnt);
}

+static int
+xfs_fs_nr_cached_objects(
+ struct super_block *sb)
+{
+ return xfs_reclaim_inodes_count(XFS_M(sb));
+}
+
+static int
+xfs_fs_free_cached_objects(
+ struct super_block *sb,
+ int nr_to_scan)
+{
+ xfs_reclaim_inodes_nr(XFS_M(sb), 0, nr_to_scan);
+ return 0;
+}
+
static const struct super_operations xfs_super_operations = {
.alloc_inode = xfs_fs_alloc_inode,
.destroy_inode = xfs_fs_destroy_inode,
@@ -1694,6 +1707,8 @@ static const struct super_operations xfs_super_operations = {
.statfs = xfs_fs_statfs,
.remount_fs = xfs_fs_remount,
.show_options = xfs_fs_show_options,
+ .nr_cached_objects = xfs_fs_nr_cached_objects,
+ .free_cached_objects = xfs_fs_free_cached_objects,
};

static struct file_system_type xfs_fs_type = {
@@ -1873,7 +1888,6 @@ init_xfs_fs(void)
goto out_cleanup_procfs;

vfs_initquota();
- xfs_inode_shrinker_init();

error = register_filesystem(&xfs_fs_type);
if (error)
@@ -1901,7 +1915,6 @@ exit_xfs_fs(void)
{
vfs_exitquota();
unregister_filesystem(&xfs_fs_type);
- xfs_inode_shrinker_destroy();
xfs_sysctl_unregister();
xfs_cleanup_procfs();
xfs_buf_terminate();
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index c881a0c..6d74a0d 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -137,7 +137,7 @@ restart:

} while ((*nr_to_scan)--);

- if (skipped) {
+ if (skipped && *nr_to_scan > 0) {
delay(1);
goto restart;
}
@@ -152,14 +152,14 @@ xfs_inode_ag_iterator(
int flags,
int tag,
int exclusive,
- int *nr_to_scan)
+ int nr_to_scan)
{
int error = 0;
int last_error = 0;
xfs_agnumber_t ag;
- int nr;

- nr = nr_to_scan ? *nr_to_scan : INT_MAX;
+ if (nr_to_scan <= 0)
+ nr_to_scan = INT_MAX;
for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
struct xfs_perag *pag;

@@ -169,18 +169,16 @@ xfs_inode_ag_iterator(
continue;
}
error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
- exclusive, &nr);
+ exclusive, &nr_to_scan);
xfs_perag_put(pag);
if (error) {
last_error = error;
if (error == EFSCORRUPTED)
break;
}
- if (nr <= 0)
+ if (nr_to_scan <= 0)
break;
}
- if (nr_to_scan)
- *nr_to_scan = nr;
return XFS_ERROR(last_error);
}

@@ -299,7 +297,7 @@ xfs_sync_data(
ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);

error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags,
- XFS_ICI_NO_TAG, 0, NULL);
+ XFS_ICI_NO_TAG, 0, 0);
if (error)
return XFS_ERROR(error);

@@ -318,7 +316,7 @@ xfs_sync_attr(
ASSERT((flags & ~SYNC_WAIT) == 0);

return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
- XFS_ICI_NO_TAG, 0, NULL);
+ XFS_ICI_NO_TAG, 0, 0);
}

STATIC int
@@ -821,100 +819,44 @@ reclaim:

}

+/*
+ * Scan a certain number of inodes for reclaim. nr_to_scan <= 0 means reclaim
+ * every inode that has the reclaim tag set.
+ */
int
-xfs_reclaim_inodes(
+xfs_reclaim_inodes_nr(
xfs_mount_t *mp,
- int mode)
+ int mode,
+ int nr_to_scan)
{
return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode,
- XFS_ICI_RECLAIM_TAG, 1, NULL);
+ XFS_ICI_RECLAIM_TAG, 1, nr_to_scan);
}

/*
- * Shrinker infrastructure.
+ * Return the number of reclaimable inodes in the filesystem for
+ * the shrinker to determine how much to reclaim.
*
- * 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.
+ * Because the inode cache may not have any reclaimable inodes in it, but will
+ * be populated as part of the higher level cleaning, we need to count all
+ * those inodes as reclaimable here as well.
*/
-static LIST_HEAD(xfs_mount_list);
-static struct rw_semaphore xfs_mount_list_lock;
-
-static int
-xfs_reclaim_inode_shrink(
- struct shrinker *shrink,
- int nr_to_scan,
- gfp_t gfp_mask)
+int
+xfs_reclaim_inodes_count(
+ xfs_mount_t *mp)
{
- struct xfs_mount *mp;
- struct xfs_perag *pag;
- xfs_agnumber_t ag;
- int reclaimable = 0;
-
- 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_ICI_RECLAIM_TAG, 1, &nr_to_scan);
- if (nr_to_scan <= 0)
- break;
- }
- up_read(&xfs_mount_list_lock);
- }
-
- 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++) {
+ xfs_agnumber_t ag;
+ int reclaimable = 0;

- pag = xfs_perag_get(mp, ag);
- if (!pag->pag_ici_init) {
- xfs_perag_put(pag);
- continue;
- }
- reclaimable += pag->pag_ici_reclaimable;
+ for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
+ struct xfs_perag *pag = xfs_perag_get(mp, ag);
+ if (!pag->pag_ici_init) {
xfs_perag_put(pag);
+ continue;
}
+ 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);
+ return reclaimable + mp->m_super->s_nr_inodes_unused;
}

-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);
-}
diff --git a/fs/xfs/linux-2.6/xfs_sync.h b/fs/xfs/linux-2.6/xfs_sync.h
index cdcbaac..c55f645 100644
--- a/fs/xfs/linux-2.6/xfs_sync.h
+++ b/fs/xfs/linux-2.6/xfs_sync.h
@@ -43,7 +43,14 @@ void xfs_quiesce_attr(struct xfs_mount *mp);

void xfs_flush_inodes(struct xfs_inode *ip);

-int xfs_reclaim_inodes(struct xfs_mount *mp, int mode);
+int xfs_reclaim_inodes_count(struct xfs_mount *mp);
+int xfs_reclaim_inodes_nr(struct xfs_mount *mp, int mode, int nr_to_scan);
+
+static inline int
+xfs_reclaim_inodes(struct xfs_mount *mp, int mode)
+{
+ return xfs_reclaim_inodes_nr(mp, mode, 0);
+}

void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
void __xfs_inode_set_reclaim_tag(struct xfs_perag *pag, struct xfs_inode *ip);
@@ -53,11 +60,6 @@ void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp, struct xfs_perag *pag,
int xfs_sync_inode_valid(struct xfs_inode *ip, struct xfs_perag *pag);
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);
+ int flags, int tag, int write_lock, int nr_to_scan);

#endif
diff --git a/fs/xfs/quota/xfs_qm_syscalls.c b/fs/xfs/quota/xfs_qm_syscalls.c
index 92b002f..f5b0e4e 100644
--- a/fs/xfs/quota/xfs_qm_syscalls.c
+++ b/fs/xfs/quota/xfs_qm_syscalls.c
@@ -894,7 +894,7 @@ xfs_qm_dqrele_all_inodes(
{
ASSERT(mp->m_quotainfo);
xfs_inode_ag_iterator(mp, xfs_dqrele_inode, flags,
- XFS_ICI_NO_TAG, 0, NULL);
+ XFS_ICI_NO_TAG, 0, 0);
}

/*------------------------------------------------------------------------*/
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 9ff48a1..4fa0bc7 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -259,7 +259,6 @@ 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 */
} xfs_mount_t;

/*
--
1.5.6.5