From 7b2e2a31f5c23b5f028af8c895137b4c512cc1c8 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:39:12 +1100 Subject: [PATCH] [XFS] Allow 64 bit machines to avoid the AIL lock during flushes When copying lsn's from the log item to the inode or dquot flush lsn, we currently grab the AIL lock. We do this because the LSN is a 64 bit quantity and it needs to be read atomically. The lock is used to guarantee atomicity for 32 bit platforms. Make the LSN copying a small function, and make the function used conditional on BITS_PER_LONG so that 64 bit machines don't need to take the AIL lock in these places. SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32349a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Christoph Hellwig --- fs/xfs/quota/xfs_dquot.c | 6 ++---- fs/xfs/xfs_inode.c | 17 +++++++---------- fs/xfs/xfs_trans_priv.h | 23 +++++++++++++++++++++++ 3 files changed, 32 insertions(+), 14 deletions(-) diff --git a/fs/xfs/quota/xfs_dquot.c b/fs/xfs/quota/xfs_dquot.c index 1e6bf39..59c1081 100644 --- a/fs/xfs/quota/xfs_dquot.c +++ b/fs/xfs/quota/xfs_dquot.c @@ -1272,10 +1272,8 @@ xfs_qm_dqflush( dqp->dq_flags &= ~(XFS_DQ_DIRTY); mp = dqp->q_mount; - /* lsn is 64 bits */ - spin_lock(&mp->m_ail_lock); - dqp->q_logitem.qli_flush_lsn = dqp->q_logitem.qli_item.li_lsn; - spin_unlock(&mp->m_ail_lock); + xfs_trans_ail_copy_lsn(mp->m_ail, &dqp->q_logitem.qli_flush_lsn, + &dqp->q_logitem.qli_item.li_lsn); /* * Attach an iodone routine so that we can remove this dquot from the diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 4eb629f..2951ffd 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -2214,9 +2214,9 @@ xfs_ifree_cluster( iip = (xfs_inode_log_item_t *)lip; ASSERT(iip->ili_logged == 1); lip->li_cb = (void(*)(xfs_buf_t*,xfs_log_item_t*)) xfs_istale_done; - spin_lock(&mp->m_ail_lock); - iip->ili_flush_lsn = iip->ili_item.li_lsn; - spin_unlock(&mp->m_ail_lock); + xfs_trans_ail_copy_lsn(mp->m_ail, + &iip->ili_flush_lsn, + &iip->ili_item.li_lsn); xfs_iflags_set(iip->ili_inode, XFS_ISTALE); pre_flushed++; } @@ -2237,9 +2237,8 @@ xfs_ifree_cluster( iip->ili_last_fields = iip->ili_format.ilf_fields; iip->ili_format.ilf_fields = 0; iip->ili_logged = 1; - spin_lock(&mp->m_ail_lock); - iip->ili_flush_lsn = iip->ili_item.li_lsn; - spin_unlock(&mp->m_ail_lock); + xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn, + &iip->ili_item.li_lsn); xfs_buf_attach_iodone(bp, (void(*)(xfs_buf_t*,xfs_log_item_t*)) @@ -3476,10 +3475,8 @@ xfs_iflush_int( iip->ili_format.ilf_fields = 0; iip->ili_logged = 1; - ASSERT(sizeof(xfs_lsn_t) == 8); /* don't lock if it shrinks */ - spin_lock(&mp->m_ail_lock); - iip->ili_flush_lsn = iip->ili_item.li_lsn; - spin_unlock(&mp->m_ail_lock); + xfs_trans_ail_copy_lsn(mp->m_ail, &iip->ili_flush_lsn, + &iip->ili_item.li_lsn); /* * Attach the function xfs_iflush_done to the inode's diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h index aa58535..708cff7 100644 --- a/fs/xfs/xfs_trans_priv.h +++ b/fs/xfs/xfs_trans_priv.h @@ -106,4 +106,27 @@ void xfsaild_wakeup(struct xfs_ail *, xfs_lsn_t); int xfsaild_start(struct xfs_ail *); void xfsaild_stop(struct xfs_ail *); +#if BITS_PER_LONG != 64 +static inline void +xfs_trans_ail_copy_lsn( + struct xfs_ail *ailp, + xfs_lsn_t *dst, + xfs_lsn_t *src) +{ + ASSERT(sizeof(xfs_lsn_t) == 8); /* don't lock if it shrinks */ + spin_lock(&ailp->xa_mount->m_ail_lock); + *dst = *src; + spin_unlock(&ailp->xa_mount->m_ail_lock); +} +#else +static inline void +xfs_trans_ail_copy_lsn( + struct xfs_ail *ailp, + xfs_lsn_t *dst, + xfs_lsn_t *src) +{ + ASSERT(sizeof(xfs_lsn_t) == 8); + *dst = *src; +} +#endif #endif /* __XFS_TRANS_PRIV_H__ */ -- 2.7.4