Commit 9bf729c0 authored by Dave Chinner's avatar Dave Chinner Committed by Alex Elder
Browse files

xfs: add a shrinker to background inode reclaim



On low memory boxes or those with highmem, kernel can OOM before the
background reclaims inodes via xfssyncd. Add a shrinker to run inode
reclaim so that it inode reclaim is expedited when memory is low.

This is more complex than it needs to be because the VM folk don't
want a context added to the shrinker infrastructure. Hence we need
to add a global list of XFS mount structures so the shrinker can
traverse them.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 79dba2ea
......@@ -1209,6 +1209,7 @@ 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);
......@@ -1622,6 +1623,8 @@ xfs_fs_fill_super(
if (error)
goto fail_vnrele;
xfs_inode_shrinker_register(mp);
kfree(mtpt);
return 0;
......@@ -1867,6 +1870,7 @@ init_xfs_fs(void)
goto out_cleanup_procfs;
vfs_initquota();
xfs_inode_shrinker_init();
error = register_filesystem(&xfs_fs_type);
if (error)
......@@ -1894,6 +1898,7 @@ exit_xfs_fs(void)
{
vfs_exitquota();
unregister_filesystem(&xfs_fs_type);
xfs_inode_shrinker_destroy();
xfs_sysctl_unregister();
xfs_cleanup_procfs();
xfs_buf_terminate();
......
......@@ -95,7 +95,8 @@ xfs_inode_ag_walk(
struct xfs_perag *pag, int flags),
int flags,
int tag,
int exclusive)
int exclusive,
int *nr_to_scan)
{
uint32_t first_index;
int last_error = 0;
......@@ -134,7 +135,7 @@ xfs_inode_ag_walk(
if (error == EFSCORRUPTED)
break;
} while (1);
} while ((*nr_to_scan)--);
if (skipped) {
delay(1);
......@@ -150,12 +151,15 @@ xfs_inode_ag_iterator(
struct xfs_perag *pag, int flags),
int flags,
int tag,
int exclusive)
int exclusive,
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;
for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
struct xfs_perag *pag;
......@@ -165,14 +169,18 @@ xfs_inode_ag_iterator(
continue;
}
error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
exclusive);
exclusive, &nr);
xfs_perag_put(pag);
if (error) {
last_error = error;
if (error == EFSCORRUPTED)
break;
}
if (nr <= 0)
break;
}
if (nr_to_scan)
*nr_to_scan = nr;
return XFS_ERROR(last_error);
}
......@@ -291,7 +299,7 @@ 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);
XFS_ICI_NO_TAG, 0, NULL);
if (error)
return XFS_ERROR(error);
......@@ -310,7 +318,7 @@ xfs_sync_attr(
ASSERT((flags & ~SYNC_WAIT) == 0);
return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
XFS_ICI_NO_TAG, 0);
XFS_ICI_NO_TAG, 0, NULL);
}
STATIC int
......@@ -673,6 +681,7 @@ __xfs_inode_set_reclaim_tag(
radix_tree_tag_set(&pag->pag_ici_root,
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
pag->pag_ici_reclaimable++;
}
/*
......@@ -705,6 +714,7 @@ __xfs_inode_clear_reclaim_tag(
{
radix_tree_tag_clear(&pag->pag_ici_root,
XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
pag->pag_ici_reclaimable--;
}
/*
......@@ -854,5 +864,93 @@ xfs_reclaim_inodes(
int mode)
{
return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode,
XFS_ICI_RECLAIM_TAG, 1);
XFS_ICI_RECLAIM_TAG, 1, NULL);
}
/*
* 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(
int nr_to_scan,
gfp_t gfp_mask)
{
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++) {
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);
}
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);
}
......@@ -53,6 +53,11 @@ 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 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);
#endif
......@@ -891,7 +891,8 @@ xfs_qm_dqrele_all_inodes(
uint flags)
{
ASSERT(mp->m_quotainfo);
xfs_inode_ag_iterator(mp, xfs_dqrele_inode, flags, XFS_ICI_NO_TAG, 0);
xfs_inode_ag_iterator(mp, xfs_dqrele_inode, flags,
XFS_ICI_NO_TAG, 0, NULL);
}
/*------------------------------------------------------------------------*/
......
......@@ -223,6 +223,7 @@ typedef struct xfs_perag {
int pag_ici_init; /* incore inode cache initialised */
rwlock_t pag_ici_lock; /* incore inode lock */
struct radix_tree_root pag_ici_root; /* incore inode cache root */
int pag_ici_reclaimable; /* reclaimable inodes */
#endif
int pagb_count; /* pagb slots in use */
xfs_perag_busy_t pagb_list[XFS_PAGB_NUM_SLOTS]; /* unstable blocks */
......
......@@ -259,6 +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 */
} xfs_mount_t;
/*
......
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