diff options
| -rw-r--r-- | man/man5/zfs-module-parameters.5 | 16 | ||||
| -rw-r--r-- | module/zfs/arc.c | 13 |
2 files changed, 26 insertions, 3 deletions
diff --git a/man/man5/zfs-module-parameters.5 b/man/man5/zfs-module-parameters.5 index d23e8022a..4671c396f 100644 --- a/man/man5/zfs-module-parameters.5 +++ b/man/man5/zfs-module-parameters.5 @@ -277,6 +277,22 @@ Default value: \fB2\fR. .sp .ne 2 .na +\fBzfs_arc_average_blocksize\fR (int) +.ad +.RS 12n +The ARC's buffer hash table is sized based on the assumption of an average +block size of \fBzfs_arc_average_blocksize\fR (default 8K). This works out +to roughly 1MB of hash table per 1GB of physical memory with 8-byte pointers. +For configurations with a known larger average block size this value can be +increased to reduce the memory footprint. + +.sp +Default value: \fB8192\fR. +.RE + +.sp +.ne 2 +.na \fBzfs_arc_grow_retry\fR (int) .ad .RS 12n diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 7c3bebabe..2c7abe6ec 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -193,6 +193,9 @@ int zfs_arc_memory_throttle_disable = 1; /* disable duplicate buffer eviction */ int zfs_disable_dup_eviction = 0; +/* average block used to size buf_hash_table */ +int zfs_arc_average_blocksize = 8 * 1024; /* 8KB */ + /* * If this percent of memory is free, don't throttle. */ @@ -1003,10 +1006,11 @@ buf_init(void) /* * The hash table is big enough to fill all of physical memory - * with an average 64K block size. The table will take up - * totalmem*sizeof(void*)/64K (eg. 128KB/GB with 8-byte pointers). + * with an average block size of zfs_arc_average_blocksize (default 8K). + * By default, the table will take up + * totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers). */ - while (hsize * 65536 < physmem * PAGESIZE) + while (hsize * zfs_arc_average_blocksize < physmem * PAGESIZE) hsize <<= 1; retry: buf_hash_table.ht_mask = hsize - 1; @@ -5657,6 +5661,9 @@ MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); module_param(zfs_disable_dup_eviction, int, 0644); MODULE_PARM_DESC(zfs_disable_dup_eviction, "disable duplicate buffer eviction"); +module_param(zfs_arc_average_blocksize, int, 0444); +MODULE_PARM_DESC(zfs_arc_average_blocksize, "Target average block size"); + module_param(zfs_arc_memory_throttle_disable, int, 0644); MODULE_PARM_DESC(zfs_arc_memory_throttle_disable, "disable memory throttle"); |