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Commit 4679b2d3 authored by David Chinner's avatar David Chinner Committed by Lachlan McIlroy
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[XFS] Reorganise xlog_t for better cacheline isolation of contention 



To reduce contention on the log in large CPU count, separate out different
parts of the xlog_t structure onto different cachelines. Move each lock
onto a different cacheline along with all the members that are
accessed/modified while that lock is held.

Also, move the debugging code into debug code.

SGI-PV: 978729
SGI-Modid: xfs-linux-melb:xfs-kern:30772a

Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent eb01c9cd

fs/xfs/xfs_log.c

+2 −3
Original line number Diff line number Diff line
@@ -1237,9 +1237,9 @@ xlog_alloc_log(xfs_mount_t *mp, 
		XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);

		iclog->ic_bp = bp;

		iclog->hic_data = bp->b_addr;



#ifdef DEBUG

		log->l_iclog_bak[i] = (xfs_caddr_t)&(iclog->ic_header);



#endif

		head = &iclog->ic_header;

		memset(head, 0, sizeof(xlog_rec_header_t));

		head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
@@ -1250,7 +1250,6 @@ xlog_alloc_log(xfs_mount_t *mp, 
		head->h_fmt = cpu_to_be32(XLOG_FMT);

		memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));





		iclog->ic_size = XFS_BUF_SIZE(bp) - log->l_iclog_hsize;

		iclog->ic_state = XLOG_STATE_ACTIVE;

		iclog->ic_log = log;

fs/xfs/xfs_log_priv.h

+30 −25
Original line number Diff line number Diff line
@@ -361,7 +361,7 @@ typedef struct xlog_iclog_fields { 


	/* reference counts need their own cacheline */

	atomic_t		ic_refcnt ____cacheline_aligned_in_smp;

} xlog_iclog_fields_t ____cacheline_aligned_in_smp;

} xlog_iclog_fields_t;



typedef union xlog_in_core2 {

	xlog_rec_header_t	hic_header;
@@ -402,8 +402,29 @@ typedef struct xlog_in_core { 
 * that round off problems won't occur when releasing partial reservations.

 */

typedef struct log {

	/* The following fields don't need locking */

	struct xfs_mount	*l_mp;	        /* mount point */

	struct xfs_buf		*l_xbuf;        /* extra buffer for log

						 * wrapping */

	struct xfs_buftarg	*l_targ;        /* buftarg of log */

	uint			l_flags;

	uint			l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */

	struct xfs_buf_cancel	**l_buf_cancel_table;

	int			l_iclog_hsize;  /* size of iclog header */

	int			l_iclog_heads;  /* # of iclog header sectors */

	uint			l_sectbb_log;   /* log2 of sector size in BBs */

	uint			l_sectbb_mask;  /* sector size (in BBs)

						 * alignment mask */

	int			l_iclog_size;	/* size of log in bytes */

	int			l_iclog_size_log; /* log power size of log */

	int			l_iclog_bufs;	/* number of iclog buffers */

	xfs_daddr_t		l_logBBstart;   /* start block of log */

	int			l_logsize;      /* size of log in bytes */

	int			l_logBBsize;    /* size of log in BB chunks */



	/* The following block of fields are changed while holding icloglock */

	sema_t			l_flushsema;    /* iclog flushing semaphore */

	sema_t			l_flushsema ____cacheline_aligned_in_smp;

						/* iclog flushing semaphore */

	int			l_flushcnt;	/* # of procs waiting on this

						 * sema */

	int			l_covered_state;/* state of "covering disk
@@ -413,27 +434,14 @@ typedef struct log { 
	xfs_lsn_t		l_tail_lsn;     /* lsn of 1st LR with unflushed

						 * buffers */

	xfs_lsn_t		l_last_sync_lsn;/* lsn of last LR on disk */

	struct xfs_mount	*l_mp;	        /* mount point */

	struct xfs_buf		*l_xbuf;        /* extra buffer for log

						 * wrapping */

	struct xfs_buftarg	*l_targ;        /* buftarg of log */

	xfs_daddr_t		l_logBBstart;   /* start block of log */

	int			l_logsize;      /* size of log in bytes */

	int			l_logBBsize;    /* size of log in BB chunks */

	int			l_curr_cycle;   /* Cycle number of log writes */

	int			l_prev_cycle;   /* Cycle number before last

						 * block increment */

	int			l_curr_block;   /* current logical log block */

	int			l_prev_block;   /* previous logical log block */

	int			l_iclog_size;	/* size of log in bytes */

	int			l_iclog_size_log; /* log power size of log */

	int			l_iclog_bufs;	/* number of iclog buffers */



	/* The following field are used for debugging; need to hold icloglock */

	char			*l_iclog_bak[XLOG_MAX_ICLOGS];



	/* The following block of fields are changed while holding grant_lock */

	spinlock_t		l_grant_lock;

	spinlock_t		l_grant_lock ____cacheline_aligned_in_smp;

	xlog_ticket_t		*l_reserve_headq;

	xlog_ticket_t		*l_write_headq;

	int			l_grant_reserve_cycle;
@@ -441,19 +449,16 @@ typedef struct log { 
	int			l_grant_write_cycle;

	int			l_grant_write_bytes;



	/* The following fields don't need locking */

#ifdef XFS_LOG_TRACE

	struct ktrace		*l_trace;

	struct ktrace		*l_grant_trace;

#endif

	uint			l_flags;

	uint			l_quotaoffs_flag; /* XFS_DQ_*, for QUOTAOFFs */

	struct xfs_buf_cancel	**l_buf_cancel_table;

	int			l_iclog_hsize;  /* size of iclog header */

	int			l_iclog_heads;  /* # of iclog header sectors */

	uint			l_sectbb_log;   /* log2 of sector size in BBs */

	uint			l_sectbb_mask;  /* sector size (in BBs)

						 * alignment mask */



	/* The following field are used for debugging; need to hold icloglock */

#ifdef DEBUG

	char			*l_iclog_bak[XLOG_MAX_ICLOGS];

#endif



} xlog_t;



#define XLOG_FORCED_SHUTDOWN(log)	((log)->l_flags & XLOG_IO_ERROR)