From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: [PATCH 06/10] repair: fix prefetch queue limiting
Date: Thu, 27 Feb 2014 20:51:11 +1100 [thread overview]
Message-ID: <1393494675-30194-7-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1393494675-30194-1-git-send-email-david@fromorbit.com>
From: Dave Chinner <dchinner@redhat.com>
The length of the prefetch queue is limited by a semaphore. To avoid
a ABBA deadlock, we only trywait on the semaphore so if we fail to
get it we can kick the IO queues before sleeping. Unfortunately,
the "need to sleep" detection is just a little wrong - it needs to
lok at errno, not err for the EAGAIN value.
Hence this queue throttling has not been working for a long time.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
repair/phase6.c | 9 ++++++++-
repair/prefetch.c | 2 +-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/repair/phase6.c b/repair/phase6.c
index 7be68b3..63359d1 100644
--- a/repair/phase6.c
+++ b/repair/phase6.c
@@ -2999,8 +2999,15 @@ traverse_function(
if (irec->ino_isa_dir == 0)
continue;
- if (pf_args)
+ if (pf_args) {
sem_post(&pf_args->ra_count);
+#ifdef XR_PF_TRACE
+ sem_getvalue(&pf_args->ra_count, &i);
+ pftrace(
+ "processing inode chunk %p in AG %d (sem count = %d)",
+ irec, agno, i);
+#endif
+ }
for (i = 0; i < XFS_INODES_PER_CHUNK; i++) {
if (inode_isadir(irec, i))
diff --git a/repair/prefetch.c b/repair/prefetch.c
index 984beda..f4f3d71 100644
--- a/repair/prefetch.c
+++ b/repair/prefetch.c
@@ -723,7 +723,7 @@ pf_queuing_worker(
irec, args->agno, i);
#endif
err = sem_trywait(&args->ra_count);
- if (err == EAGAIN) {
+ if (err < 0 && errno == EAGAIN) {
/*
* Kick the queue once we have reached the limit;
* without this the threads processing the inodes
--
1.8.4.rc3
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next prev parent reply other threads:[~2014-02-27 9:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-27 9:51 [PATCH 00/10, v3] xfsprogs: reapir scalability and fixes Dave Chinner
2014-02-27 9:51 ` [PATCH 01/10] repair: translation lookups limit scalability Dave Chinner
2014-02-27 9:51 ` [PATCH 02/10] repair: per AG locks contend for cachelines Dave Chinner
2014-02-27 9:51 ` [PATCH 03/10] libxfs: buffer cache hashing is suboptimal Dave Chinner
2014-02-27 9:51 ` [PATCH 04/10] repair: limit auto-striding concurrency apprpriately Dave Chinner
2014-02-27 9:51 ` [PATCH 05/10] repair: use a listhead for the dotdot list Dave Chinner
2014-02-27 9:51 ` Dave Chinner [this message]
2014-02-27 9:51 ` [PATCH 07/10] repair: BMBT prefetch needs to be CRC aware Dave Chinner
2014-02-27 9:51 ` [PATCH 08/10] repair: factor out threading setup code Dave Chinner
2014-02-27 14:05 ` Brian Foster
2014-02-27 9:51 ` [PATCH 09/10] repair: prefetch runs too far ahead Dave Chinner
2014-02-27 14:08 ` Brian Foster
2014-02-27 20:01 ` Dave Chinner
2014-02-27 20:24 ` Dave Chinner
2014-02-27 20:45 ` Brian Foster
2014-02-27 9:51 ` [PATCH 10/10] libxfs: remove a couple of locks Dave Chinner
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