From aa7d06a98a2b3b0d864aadd310113c52b946b842 Mon Sep 17 00:00:00 2001 From: George Wilson Date: Mon, 31 Mar 2014 17:22:55 -0700 Subject: [PATCH] Illumos #4101 finer-grained control of metaslab_debug Today the metaslab_debug logic performs two tasks: - load all metaslabs on import/open - don't unload metaslabs at the end of spa_sync This change provides knobs for each of these independently. References: https://illumos.org/issues/4101 https://github.com/illumos/illumos-gate/commit/0713e23 Notes: 1) This is a small piece of the metaslab improvement patch from Illumos. It was worth bringing over before the rest, since it's low risk and it can be useful on fragmented pools (e.g. Lustre MDTs). metaslab_debug_unload would give the performance benefit of the old metaslab_debug option without causing unwanted delay during pool import. Ported-by: Ned Bass Signed-off-by: Brian Behlendorf Closes #2227 --- man/man5/zfs-module-parameters.5 | 15 +++++++++++++-- module/zfs/metaslab.c | 20 ++++++++++++++------ 2 files changed, 27 insertions(+), 8 deletions(-) diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5 index e0d44d22c1..815c856c06 100644 --- a/man/man5/zfs-module-parameters.5 +++ b/man/man5/zfs-module-parameters.5 @@ -137,10 +137,21 @@ Default value: \fB8,388,608\fR. .sp .ne 2 .na -\fBmetaslab_debug\fR (int) +\fBmetaslab_debug_load\fR (int) .ad .RS 12n -Keep space maps in core to verify frees +Load all metaslabs during pool import. +.sp +Use \fB1\fR for yes and \fB0\fR for no (default). +.RE + +.sp +.ne 2 +.na +\fBmetaslab_debug_unload\fR (int) +.ad +.RS 12n +Prevent metaslabs from being unloaded. .sp Use \fB1\fR for yes and \fB0\fR for no (default). .RE diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c index 6356f79502..32ffdfb985 100644 --- a/module/zfs/metaslab.c +++ b/module/zfs/metaslab.c @@ -81,9 +81,14 @@ int zfs_mg_alloc_failures = 0; int zfs_mg_noalloc_threshold = 0; /* - * Metaslab debugging: when set, keeps all space maps in core to verify frees. + * When set will load all metaslabs when pool is first opened. */ -int metaslab_debug = 0; +int metaslab_debug_load = 0; + +/* + * When set will prevent metaslabs from being unloaded. + */ +int metaslab_debug_unload = 0; /* * Minimum size which forces the dynamic allocator to change @@ -846,7 +851,7 @@ metaslab_init(metaslab_group_t *mg, space_map_obj_t *smo, metaslab_group_add(mg, msp); - if (metaslab_debug && smo->smo_object != 0) { + if (metaslab_debug_load && smo->smo_object != 0) { mutex_enter(&msp->ms_lock); VERIFY(space_map_load(msp->ms_map, mg->mg_class->mc_ops, SM_FREE, smo, spa_meta_objset(vd->vdev_spa)) == 0); @@ -1407,7 +1412,7 @@ metaslab_sync_done(metaslab_t *msp, uint64_t txg) if (msp->ms_allocmap[(txg + t) & TXG_MASK]->sm_space) evictable = 0; - if (evictable && !metaslab_debug) + if (evictable && !metaslab_debug_unload) space_map_unload(sm); } @@ -2109,6 +2114,9 @@ metaslab_check_free(spa_t *spa, const blkptr_t *bp) } #if defined(_KERNEL) && defined(HAVE_SPL) -module_param(metaslab_debug, int, 0644); -MODULE_PARM_DESC(metaslab_debug, "keep space maps in core to verify frees"); +module_param(metaslab_debug_load, int, 0644); +MODULE_PARM_DESC(metaslab_debug_load, "load all metaslabs during pool import"); + +module_param(metaslab_debug_unload, int, 0644); +MODULE_PARM_DESC(metaslab_debug_unload, "prevent metaslabs from being unloaded"); #endif /* _KERNEL && HAVE_SPL */