bump version to 0.7.7-pve1~bpo9

[zfsonlinux.git] / zfs-patches / 0054-Fix-MMP-write-frequency-for-large-pools.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Mon, 12 Mar 2018 11:26:05 -0700
Subject: [PATCH] Fix MMP write frequency for large pools
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When a single pool contains more vdevs than the CONFIG_HZ for
for the kernel the mmp thread will not delay properly.  Switch
to using cv_timedwait_sig_hires() to handle higher resolution
delays.

This issue was reported on Arch Linux where HZ defaults to only
100 and this could be fairly easily reproduced with a reasonably
large pool.  Most distribution kernels set CONFIG_HZ=250 or
CONFIG_HZ=1000 and thus are unlikely to be impacted.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Olaf Faaland <faaland1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7205
Closes #7289
(cherry picked from commit c30e716c8149b7df7cf968373c22aa00b48d17b8)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 lib/libspl/include/sys/time.h | 6 +++++-
 module/zfs/mmp.c              | 6 +++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/libspl/include/sys/time.h b/lib/libspl/include/sys/time.h
index f05fcaa1c..dc645fa5c 100644
--- a/lib/libspl/include/sys/time.h
+++ b/lib/libspl/include/sys/time.h
@@ -54,10 +54,14 @@
 #define	MSEC2NSEC(m)    ((hrtime_t)(m) * (NANOSEC / MILLISEC))
 #endif
 
-#ifndef NSEC2MSEC
+#ifndef	NSEC2MSEC
 #define	NSEC2MSEC(n)    ((n) / (NANOSEC / MILLISEC))
 #endif
 
+#ifndef USEC2NSEC
+#define	USEC2NSEC(m)	((hrtime_t)(m) * (NANOSEC / MICROSEC))
+#endif
+
 #ifndef	NSEC2SEC
 #define	NSEC2SEC(n)	((n) / (NANOSEC / SEC))
 #endif
diff --git a/module/zfs/mmp.c b/module/zfs/mmp.c
index 15eea41ab..dc5c6a74f 100644
--- a/module/zfs/mmp.c
+++ b/module/zfs/mmp.c
@@ -462,9 +462,9 @@ mmp_thread(spa_t *spa)
 			mmp_write_uberblock(spa);
 
 		CALLB_CPR_SAFE_BEGIN(&cpr);
-		(void) cv_timedwait_sig(&mmp->mmp_thread_cv,
-		    &mmp->mmp_thread_lock, ddi_get_lbolt() +
-		    ((next_time - gethrtime()) / (NANOSEC / hz)));
+		(void) cv_timedwait_sig_hires(&mmp->mmp_thread_cv,
+		    &mmp->mmp_thread_lock, next_time, USEC2NSEC(1),
+		    CALLOUT_FLAG_ABSOLUTE);
 		CALLB_CPR_SAFE_END(&cpr, &mmp->mmp_thread_lock);
 	}
 
-- 
2.14.2