Set spl_kmem_cache_slab_limit=16384 to default

For small objects the Linux slab allocator should be used to make the most efficient use of the memory. However, large objects are not supported by the Linux slab and therefore the SPL implementation is preferred. A cutoff of 16K was determined to be optimal for architectures using 4K pages. Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: DHE <[email protected]> Issue #356 Closes #379
openzfs · Aug 8, 2014 · f2297b5 · f2297b5
1 parent c1aef26
commit f2297b5
Showing 1 changed file with 10 additions and 0 deletions.
diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
@@ -81,7 +81,17 @@ unsigned int spl_kmem_cache_max_size = 32;
 module_param(spl_kmem_cache_max_size, uint, 0644);
 MODULE_PARM_DESC(spl_kmem_cache_max_size, "Maximum size of slab in MB");
 
+/*
+ * For small objects the Linux slab allocator should be used to make the most
+ * efficient use of the memory.  However, large objects are not supported by
+ * the Linux slab and therefore the SPL implementation is preferred.  A cutoff
+ * of 16K was determined to be optimal for architectures using 4K pages.
+ */
+#if PAGE_SIZE == 4096
+unsigned int spl_kmem_cache_slab_limit = 16384;
+#else
 unsigned int spl_kmem_cache_slab_limit = 0;
+#endif
 module_param(spl_kmem_cache_slab_limit, uint, 0644);
 MODULE_PARM_DESC(spl_kmem_cache_slab_limit,
     "Objects less than N bytes use the Linux slab");