diff options
| -rw-r--r-- | man/man5/zfs-module-parameters.5 | 18 | ||||
| -rw-r--r-- | module/zfs/arc.c | 21 |
2 files changed, 37 insertions, 2 deletions
diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5 index 77f1af6d5..2fbab1d01 100644 --- a/man/man5/zfs-module-parameters.5 +++ b/man/man5/zfs-module-parameters.5 @@ -702,6 +702,24 @@ Default value: \fB5\fR. .sp .ne 2 .na +\fBzfs_arc_pc_percent\fR (uint) +.ad +.RS 12n +Percent of pagecache to reclaim arc to + +This tunable allows ZFS arc to play more nicely with the kernel's LRU +pagecache. It can guarantee that the arc size won't collapse under scanning +pressure on the pagecache, yet still allows arc to be reclaimed down to +zfs_arc_min if necessary. This value is specified as percent of pagecache +size (as measured by NR_FILE_PAGES) where that percent may exceed 100. This +only operates during memory pressure/reclaim. +.sp +Default value: \fB0\fR (disabled). +.RE + +.sp +.ne 2 +.na \fBzfs_arc_sys_free\fR (ulong) .ad .RS 12n diff --git a/module/zfs/arc.c b/module/zfs/arc.c index ce9246061..acf98dd2d 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -319,6 +319,11 @@ static int arc_p_min_shift = 4; /* log2(fraction of arc to reclaim) */ static int arc_shrink_shift = 7; +/* percent of pagecache to reclaim arc to */ +#ifdef _KERNEL +static uint_t zfs_arc_pc_percent = 0; +#endif + /* * log2(fraction of ARC which must be free to allow growing). * I.e. If there is less than arc_c >> arc_no_grow_shift free memory, @@ -4377,10 +4382,18 @@ arc_evictable_memory(void) refcount_count(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]); uint64_t arc_dirty = MAX((int64_t)arc_size - (int64_t)arc_clean, 0); - if (arc_dirty >= arc_c_min) + /* + * Scale reported evictable memory in proportion to page cache, cap + * at specified min/max. + */ + uint64_t min = (ptob(global_page_state(NR_FILE_PAGES)) / 100) * + zfs_arc_pc_percent; + min = MAX(arc_c_min, MIN(arc_c_max, min)); + + if (arc_dirty >= min) return (arc_clean); - return (MAX((int64_t)arc_size - (int64_t)arc_c_min, 0)); + return (MAX((int64_t)arc_size - (int64_t)min, 0)); } /* @@ -7754,6 +7767,10 @@ MODULE_PARM_DESC(zfs_arc_p_dampener_disable, "disable arc_p adapt dampener"); module_param(zfs_arc_shrink_shift, int, 0644); MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); +module_param(zfs_arc_pc_percent, uint, 0644); +MODULE_PARM_DESC(zfs_arc_pc_percent, + "Percent of pagecache to reclaim arc to"); + module_param(zfs_arc_p_min_shift, int, 0644); MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p"); |