[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: David Chinner <dgc@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

1 files changed, 2 insertions, 3 deletions

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 3cf115d8de75..319b98eb410c 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -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;