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6d6ccedd76
In examining a flame graph of time spent running xfs_scrub on various filesystems, I noticed that we spent nearly 7% of the total runtime on allocating a zeroed 65k buffer for every SCRUB_TYPE_XATTR invocation. We do this even if none of the attribute values were anywhere near 64k in size, even if there were no attribute blocks to check space on, and even if it just turns out there are no attributes at all. Therefore, rearrange the xattr buffer setup code to support reallocating with a bigger buffer and redistribute the callers of that function so that we only allocate memory just prior to needing it, and only allocate as much as we need. If we can't get memory with the ILOCK held we'll bail out with EDEADLOCK which will allocate the maximum memory. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
71 lines
1.8 KiB
C
71 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Copyright (C) 2019 Oracle. All Rights Reserved.
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*/
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#ifndef __XFS_SCRUB_ATTR_H__
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#define __XFS_SCRUB_ATTR_H__
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/*
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* Temporary storage for online scrub and repair of extended attributes.
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*/
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struct xchk_xattr_buf {
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/* Size of @buf, in bytes. */
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size_t sz;
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/*
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* Memory buffer -- either used for extracting attr values while
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* walking the attributes; or for computing attr block bitmaps when
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* checking the attribute tree.
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*
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* Each bitmap contains enough bits to track every byte in an attr
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* block (rounded up to the size of an unsigned long). The attr block
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* used space bitmap starts at the beginning of the buffer; the free
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* space bitmap follows immediately after; and we have a third buffer
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* for storing intermediate bitmap results.
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*/
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uint8_t buf[0];
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};
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/* A place to store attribute values. */
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static inline uint8_t *
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xchk_xattr_valuebuf(
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struct xfs_scrub *sc)
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{
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struct xchk_xattr_buf *ab = sc->buf;
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return ab->buf;
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}
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/* A bitmap of space usage computed by walking an attr leaf block. */
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static inline unsigned long *
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xchk_xattr_usedmap(
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struct xfs_scrub *sc)
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{
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struct xchk_xattr_buf *ab = sc->buf;
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return (unsigned long *)ab->buf;
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}
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/* A bitmap of free space computed by walking attr leaf block free info. */
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static inline unsigned long *
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xchk_xattr_freemap(
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struct xfs_scrub *sc)
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{
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return xchk_xattr_usedmap(sc) +
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BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
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}
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/* A bitmap used to hold temporary results. */
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static inline unsigned long *
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xchk_xattr_dstmap(
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struct xfs_scrub *sc)
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{
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return xchk_xattr_freemap(sc) +
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BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
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}
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int xchk_setup_xattr_buf(struct xfs_scrub *sc, size_t value_size,
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xfs_km_flags_t flags);
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#endif /* __XFS_SCRUB_ATTR_H__ */
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