svn commit: r207481 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Martin Matuska]

Author: mm
Date: Sat May  1 20:44:37 2010
New Revision: 207481
URL: http://svn.freebsd.org/changeset/base/207481

Log:
  Add sysctl and loader tunable vfs.zfs.txg.write_limit_override.
  This tunable improves fine-tuning of ZFS write throttling.
  
  PR:		kern/146108
  Suggested by:	Nikolay Denev <ndenev at gmail.com>
  Approved by:	pjd, delphij (mentor)
  MFC after:	2 weeks

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/txg.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/txg.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/txg.c	Sat May  1 19:53:15 2010	(r207480)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/txg.c	Sat May  1 20:44:37 2010	(r207481)
@@ -38,6 +38,7 @@ static void txg_quiesce_thread(void *arg
 
 int zfs_txg_timeout = 30;	/* max seconds worth of delta per txg */
 extern int zfs_txg_synctime;
+extern uint64_t zfs_write_limit_override;
 
 SYSCTL_DECL(_vfs_zfs);
 SYSCTL_NODE(_vfs_zfs, OID_AUTO, txg, CTLFLAG_RW, 0,
@@ -48,6 +49,11 @@ SYSCTL_INT(_vfs_zfs_txg, OID_AUTO, timeo
 TUNABLE_INT("vfs.zfs.txg.synctime", &zfs_txg_synctime);
 SYSCTL_INT(_vfs_zfs_txg, OID_AUTO, synctime, CTLFLAG_RDTUN, &zfs_txg_synctime,
     0, "Target seconds to sync a txg");
+TUNABLE_QUAD("vfs.zfs.txg.write_limit_override", &zfs_write_limit_override);
+SYSCTL_QUAD(_vfs_zfs_txg, OID_AUTO, write_limit_override, CTLFLAG_RW,
+    &zfs_write_limit_override, 0,
+    "Override maximum size of a txg to this size in bytes, "
+    "value of 0 means don't override");
 
 /*
  * Prepare the txg subsystem.