Thread (27 messages) 27 messages, 7 authors, 2021-02-17

Re: [PATCH 1/5] xfs: log stripe roundoff is a property of the log

From: Brian Foster <hidden>
Date: 2021-01-28 14:59:49

On Thu, Jan 28, 2021 at 03:41:50PM +1100, Dave Chinner wrote:
From: Dave Chinner <redacted>

We don't need to look at the xfs_mount and superblock every time we
need to do an iclog roundoff calculation. The property is fixed for
the life of the log, so store the roundoff in the log at mount time
and use that everywhere.

On a debug build:

$ size fs/xfs/xfs_log.o.*
   text	   data	    bss	    dec	    hex	filename
  27360	    560	      8	  27928	   6d18	fs/xfs/xfs_log.o.orig
  27219	    560	      8	  27787	   6c8b	fs/xfs/xfs_log.o.patched

Signed-off-by: Dave Chinner <redacted>
---
 fs/xfs/libxfs/xfs_log_format.h |  3 --
 fs/xfs/xfs_log.c               | 60 +++++++++++++++-------------------
 fs/xfs/xfs_log_priv.h          |  2 ++
 3 files changed, 28 insertions(+), 37 deletions(-)
...
quoted hunk ↗ jump to hunk
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 58699881c100..c5f507c24577 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1400,6 +1400,12 @@ xlog_alloc_log(
 	xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0);
 	log->l_curr_cycle  = 1;	    /* 0 is bad since this is initial value */
 
+	/* roundoff padding for transaction data and one for commit record */
I don't follow this comment. What do you mean by "... and one for commit
record?"
+	if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1)
+		log->l_iclog_roundoff = mp->m_sb.sb_logsunit;
+	else
+		log->l_iclog_roundoff = BBSIZE;
+
 	xlog_grant_head_init(&log->l_reserve_head);
 	xlog_grant_head_init(&log->l_write_head);
 
...
quoted hunk ↗ jump to hunk
@@ -3485,18 +3475,20 @@ xfs_log_calc_unit_res(
 	/* for commit-rec LR header - note: padding will subsume the ophdr */
 	unit_bytes += log->l_iclog_hsize;
 
-	/* for roundoff padding for transaction data and one for commit record */
-	if (xfs_sb_version_haslogv2(&mp->m_sb) && mp->m_sb.sb_logsunit > 1) {
-		/* log su roundoff */
-		unit_bytes += 2 * mp->m_sb.sb_logsunit;
-	} else {
-		/* BB roundoff */
-		unit_bytes += 2 * BBSIZE;
-        }
+	/* roundoff padding for transaction data and one for commit record */
+	unit_bytes += log->l_iclog_roundoff;
 
 	return unit_bytes;
 }
 
+int
+xfs_log_calc_unit_res(
+	struct xfs_mount	*mp,
+	int			unit_bytes)
+{
+	return xlog_calc_unit_res(mp->m_log, unit_bytes);
+}
+
Could this be moved to the header as an inline? Otherwise looks
reasonable.

Brian
quoted hunk ↗ jump to hunk
 /*
  * Allocate and initialise a new log ticket.
  */
@@ -3513,7 +3505,7 @@ xlog_ticket_alloc(
 
 	tic = kmem_cache_zalloc(xfs_log_ticket_zone, GFP_NOFS | __GFP_NOFAIL);
 
-	unit_res = xfs_log_calc_unit_res(log->l_mp, unit_bytes);
+	unit_res = xlog_calc_unit_res(log, unit_bytes);
 
 	atomic_set(&tic->t_ref, 1);
 	tic->t_task		= current;
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index 1c6fdbf3d506..037950cf1061 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -436,6 +436,8 @@ struct xlog {
 #endif
 	/* log recovery lsn tracking (for buffer submission */
 	xfs_lsn_t		l_recovery_lsn;
+
+	uint32_t		l_iclog_roundoff;/* padding roundoff */
 };
 
 #define XLOG_BUF_CANCEL_BUCKET(log, blkno) \
-- 
2.28.0
  
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