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Commit 70e60ce7 authored by Dave Chinner's avatar Dave Chinner Committed by Dave Chinner
Browse files

xfs: convert inode shrinker to per-filesystem contexts 



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: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 7f8275d0

fs/xfs/linux-2.6/xfs_super.c

+0 −2
Original line number Diff line number Diff line
@@ -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();

fs/xfs/linux-2.6/xfs_sync.c

+14 −48
Original line number Diff line number Diff line
@@ -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_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);

	}

	}

	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);

}

fs/xfs/linux-2.6/xfs_sync.h

+0 −2
Original line number Diff line number Diff line
@@ -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);

fs/xfs/xfs_mount.h

+1 −1
Original line number Diff line number Diff line
@@ -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;



/*