Commit 12eba65b authored Mar 24, 2020 by Dave Chinner Committed by Darrick J. Wong Mar 27, 2020

xfs: Improve metadata buffer reclaim accountability



The buffer cache shrinker frees more than just the xfs_buf slab
objects - it also frees the pages attached to the buffers. Make sure
the memory reclaim code accounts for this memory being freed
correctly, similar to how the inode shrinker accounts for pages
freed from the page cache due to mapping invalidation.

We also need to make sure that the mm subsystem knows these are
reclaimable objects. We provide the memory reclaim subsystem with a
a shrinker to reclaim xfs_bufs, so we should really mark the slab
that way.

We also have a lot of xfs_bufs in a busy system, spread them around
like we do inodes.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

parent 2def2845

fs/xfs/xfs_buf.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -327,6 +327,9 @@ xfs_buf_free(

		__free_page(page);
		}
		if (current->reclaim_state)
		current->reclaim_state->reclaimed_slab +=
		bp->b_page_count;
		} else if (bp->b_flags & _XBF_KMEM)
		kmem_free(bp->b_addr);
		_xfs_buf_free_pages(bp);
		@@ -2114,9 +2117,11 @@ xfs_buf_delwri_pushbuf(
		int __init
		xfs_buf_init(void)
		{
		xfs_buf_zone = kmem_cache_create("xfs_buf",
		sizeof(struct xfs_buf), 0,
		SLAB_HWCACHE_ALIGN, NULL);
		xfs_buf_zone = kmem_cache_create("xfs_buf", sizeof(struct xfs_buf), 0,
		SLAB_HWCACHE_ALIGN \|
		SLAB_RECLAIM_ACCOUNT \|
		SLAB_MEM_SPREAD,
		NULL);
		if (!xfs_buf_zone)
		goto out;

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