Commit ef5a83b7 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: use shifting and masking when converting rt extents, if possible 



Avoid the costs of integer division (32-bit and 64-bit) if the realtime
extent size is a power of two.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 5f57f730

fs/xfs/libxfs/xfs_rtbitmap.h

+29 −0
Original line number Diff line number Diff line
@@ -11,6 +11,9 @@ xfs_rtx_to_rtb( 
	struct xfs_mount	*mp,

	xfs_rtxnum_t		rtx)

{

	if (mp->m_rtxblklog >= 0)

		return rtx << mp->m_rtxblklog;



	return rtx * mp->m_sb.sb_rextsize;

}
@@ -19,6 +22,9 @@ xfs_rtxlen_to_extlen( 
	struct xfs_mount	*mp,

	xfs_rtxlen_t		rtxlen)

{

	if (mp->m_rtxblklog >= 0)

		return rtxlen << mp->m_rtxblklog;



	return rtxlen * mp->m_sb.sb_rextsize;

}
@@ -28,6 +34,9 @@ xfs_extlen_to_rtxmod( 
	struct xfs_mount	*mp,

	xfs_extlen_t		len)

{

	if (mp->m_rtxblklog >= 0)

		return len & mp->m_rtxblkmask;



	return len % mp->m_sb.sb_rextsize;

}
@@ -36,6 +45,9 @@ xfs_extlen_to_rtxlen( 
	struct xfs_mount	*mp,

	xfs_extlen_t		len)

{

	if (mp->m_rtxblklog >= 0)

		return len >> mp->m_rtxblklog;



	return len / mp->m_sb.sb_rextsize;

}
@@ -45,6 +57,9 @@ xfs_rtb_to_rtx( 
	struct xfs_mount	*mp,

	xfs_rtblock_t		rtbno)

{

	if (likely(mp->m_rtxblklog >= 0))

		return rtbno >> mp->m_rtxblklog;



	return div_u64(rtbno, mp->m_sb.sb_rextsize);

}
@@ -54,6 +69,9 @@ xfs_rtb_to_rtxoff( 
	struct xfs_mount	*mp,

	xfs_rtblock_t		rtbno)

{

	if (likely(mp->m_rtxblklog >= 0))

		return rtbno & mp->m_rtxblkmask;



	return do_div(rtbno, mp->m_sb.sb_rextsize);

}
@@ -67,6 +85,11 @@ xfs_rtb_to_rtxrem( 
	xfs_rtblock_t		rtbno,

	xfs_extlen_t		*off)

{

	if (likely(mp->m_rtxblklog >= 0)) {

		*off = rtbno & mp->m_rtxblkmask;

		return rtbno >> mp->m_rtxblklog;

	}



	return div_u64_rem(rtbno, mp->m_sb.sb_rextsize, off);

}
@@ -79,6 +102,12 @@ xfs_rtb_to_rtxup( 
	struct xfs_mount	*mp,

	xfs_rtblock_t		rtbno)

{

	if (likely(mp->m_rtxblklog >= 0)) {

		if (rtbno & mp->m_rtxblkmask)

			return (rtbno >> mp->m_rtxblklog) + 1;

		return rtbno >> mp->m_rtxblklog;

	}



	if (do_div(rtbno, mp->m_sb.sb_rextsize))

		rtbno++;

	return rtbno;

fs/xfs/libxfs/xfs_sb.c

+2 −0
Original line number Diff line number Diff line
@@ -975,6 +975,8 @@ xfs_sb_mount_common( 
	mp->m_blockmask = sbp->sb_blocksize - 1;

	mp->m_blockwsize = sbp->sb_blocksize >> XFS_WORDLOG;

	mp->m_blockwmask = mp->m_blockwsize - 1;

	mp->m_rtxblklog = log2_if_power2(sbp->sb_rextsize);

	mp->m_rtxblkmask = mask64_if_power2(sbp->sb_rextsize);



	mp->m_alloc_mxr[0] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 1);

	mp->m_alloc_mxr[1] = xfs_allocbt_maxrecs(mp, sbp->sb_blocksize, 0);

fs/xfs/xfs_linux.h

+12 −0
Original line number Diff line number Diff line
@@ -198,6 +198,18 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y) 
	return x;

}



/* If @b is a power of 2, return log2(b).  Else return -1. */

static inline int8_t log2_if_power2(unsigned long b)

{

	return is_power_of_2(b) ? ilog2(b) : -1;

}



/* If @b is a power of 2, return a mask of the lower bits, else return zero. */

static inline unsigned long long mask64_if_power2(unsigned long b)

{

	return is_power_of_2(b) ? b - 1 : 0;

}



int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count,

		char *data, enum req_op op);

fs/xfs/xfs_mount.h

+2 −0
Original line number Diff line number Diff line
@@ -119,6 +119,7 @@ typedef struct xfs_mount { 
	uint8_t			m_blkbb_log;	/* blocklog - BBSHIFT */

	uint8_t			m_agno_log;	/* log #ag's */

	uint8_t			m_sectbb_log;	/* sectlog - BBSHIFT */

	int8_t			m_rtxblklog;	/* log2 of rextsize, if possible */

	uint			m_blockmask;	/* sb_blocksize-1 */

	uint			m_blockwsize;	/* sb_blocksize in words */

	uint			m_blockwmask;	/* blockwsize-1 */
@@ -152,6 +153,7 @@ typedef struct xfs_mount { 
	uint64_t		m_features;	/* active filesystem features */

	uint64_t		m_low_space[XFS_LOWSP_MAX];

	uint64_t		m_low_rtexts[XFS_LOWSP_MAX];

	uint64_t		m_rtxblkmask;	/* rt extent block mask */

	struct xfs_ino_geometry	m_ino_geo;	/* inode geometry */

	struct xfs_trans_resv	m_resv;		/* precomputed res values */

						/* low free space thresholds */

fs/xfs/xfs_rtalloc.c

+1 −0
Original line number Diff line number Diff line
@@ -1054,6 +1054,7 @@ xfs_growfs_rt( 
		 * Calculate new sb and mount fields for this round.

		 */

		nsbp->sb_rextsize = in->extsize;

		nmp->m_rtxblklog = -1; /* don't use shift or masking */

		nsbp->sb_rbmblocks = bmbno + 1;

		nrblocks_step = (bmbno + 1) * NBBY * nsbp->sb_blocksize *

				nsbp->sb_rextsize;