mm/slub: unify all sl[au]b parameters with "slab_$param"

Since the SLAB allocator has been removed, so we can clean up the
sl[au]b_$params. With only one slab allocator left, it's better to use the
generic "slab" term instead of "slub" which is an implementation detail,
which is pointed out by Vlastimil Babka. For more information please see
[1]. Hence, we are going to use "slab_$param" as the primary prefix.

This patch is changing the following slab parameters
- slub_max_order
- slub_min_order
- slub_min_objects
- slub_debug
to
- slab_max_order
- slab_min_order
- slab_min_objects
- slab_debug
as the primary slab parameters for all references of them in docs and
comments. But this patch won't change variables and functions inside
slub as we will have wider slub/slab change.

Meanwhile, "slub_$params" can also be passed by command line, which is
to keep backward compatibility. Also mark all "slub_$params" as legacy.

Remove the separate descriptions for slub_[no]merge, append legacy tip
for them at the end of descriptions of slab_[no]merge.

[1] https://lore.kernel.org/linux-mm/7512b350-4317-21a0-fab3-4101bc4d8f7a@suse.cz/

Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

1 files changed, 23 insertions, 18 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 2ef88bbf56a3..e66bc888d23b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -295,7 +295,7 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 
 /*
  * Debugging flags that require metadata to be stored in the slab.  These get
- * disabled when slub_debug=O is used and a cache's min order increases with
+ * disabled when slab_debug=O is used and a cache's min order increases with
  * metadata.
  */
 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
@@ -1616,7 +1616,7 @@ static inline int free_consistency_checks(struct kmem_cache *s,
 }
 
 /*
- * Parse a block of slub_debug options. Blocks are delimited by ';'
+ * Parse a block of slab_debug options. Blocks are delimited by ';'
  *
  * @str:    start of block
  * @flags:  returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
@@ -1677,7 +1677,7 @@ parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
 			break;
 		default:
 			if (init)
-				pr_err("slub_debug option '%c' unknown. skipped\n", *str);
+				pr_err("slab_debug option '%c' unknown. skipped\n", *str);
 		}
 	}
 check_slabs:
@@ -1736,7 +1736,7 @@ static int __init setup_slub_debug(char *str)
 	/*
 	 * For backwards compatibility, a single list of flags with list of
 	 * slabs means debugging is only changed for those slabs, so the global
-	 * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
+	 * slab_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
 	 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
 	 * long as there is no option specifying flags without a slab list.
 	 */
@@ -1760,7 +1760,8 @@ out:
 	return 1;
 }
 
-__setup("slub_debug", setup_slub_debug);
+__setup("slab_debug", setup_slub_debug);
+__setup_param("slub_debug", slub_debug, setup_slub_debug, 0);
 
 /*
  * kmem_cache_flags - apply debugging options to the cache
@@ -1770,7 +1771,7 @@ __setup("slub_debug", setup_slub_debug);
  *
  * Debug option(s) are applied to @flags. In addition to the debug
  * option(s), if a slab name (or multiple) is specified i.e.
- * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
+ * slab_debug=<Debug-Options>,<slab name1>,<slab name2> ...
  * then only the select slabs will receive the debug option(s).
  */
 slab_flags_t kmem_cache_flags(unsigned int object_size,
@@ -3263,7 +3264,7 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
 		oo_order(s->min));
 
 	if (oo_order(s->min) > get_order(s->object_size))
-		pr_warn("  %s debugging increased min order, use slub_debug=O to disable.\n",
+		pr_warn("  %s debugging increased min order, use slab_debug=O to disable.\n",
 			s->name);
 
 	for_each_kmem_cache_node(s, node, n) {
@@ -3792,11 +3793,11 @@ void slab_post_alloc_hook(struct kmem_cache *s,	struct obj_cgroup *objcg,
 		zero_size = orig_size;
 
 	/*
-	 * When slub_debug is enabled, avoid memory initialization integrated
+	 * When slab_debug is enabled, avoid memory initialization integrated
 	 * into KASAN and instead zero out the memory via the memset below with
 	 * the proper size. Otherwise, KASAN might overwrite SLUB redzones and
 	 * cause false-positive reports. This does not lead to a performance
-	 * penalty on production builds, as slub_debug is not intended to be
+	 * penalty on production builds, as slab_debug is not intended to be
 	 * enabled there.
 	 */
 	if (__slub_debug_enabled())
@@ -4702,8 +4703,8 @@ static unsigned int slub_min_objects;
  * activity on the partial lists which requires taking the list_lock. This is
  * less a concern for large slabs though which are rarely used.
  *
- * slub_max_order specifies the order where we begin to stop considering the
- * number of objects in a slab as critical. If we reach slub_max_order then
+ * slab_max_order specifies the order where we begin to stop considering the
+ * number of objects in a slab as critical. If we reach slab_max_order then
  * we try to keep the page order as low as possible. So we accept more waste
  * of space in favor of a small page order.
  *
@@ -4770,14 +4771,14 @@ static inline int calculate_order(unsigned int size)
 	 * and backing off gradually.
 	 *
 	 * We start with accepting at most 1/16 waste and try to find the
-	 * smallest order from min_objects-derived/slub_min_order up to
-	 * slub_max_order that will satisfy the constraint. Note that increasing
+	 * smallest order from min_objects-derived/slab_min_order up to
+	 * slab_max_order that will satisfy the constraint. Note that increasing
 	 * the order can only result in same or less fractional waste, not more.
 	 *
 	 * If that fails, we increase the acceptable fraction of waste and try
 	 * again. The last iteration with fraction of 1/2 would effectively
 	 * accept any waste and give us the order determined by min_objects, as
-	 * long as at least single object fits within slub_max_order.
+	 * long as at least single object fits within slab_max_order.
 	 */
 	for (unsigned int fraction = 16; fraction > 1; fraction /= 2) {
 		order = calc_slab_order(size, min_order, slub_max_order,
@@ -4787,7 +4788,7 @@ static inline int calculate_order(unsigned int size)
 	}
 
 	/*
-	 * Doh this slab cannot be placed using slub_max_order.
+	 * Doh this slab cannot be placed using slab_max_order.
 	 */
 	order = get_order(size);
 	if (order <= MAX_PAGE_ORDER)
@@ -5313,7 +5314,9 @@ static int __init setup_slub_min_order(char *str)
 	return 1;
 }
 
-__setup("slub_min_order=", setup_slub_min_order);
+__setup("slab_min_order=", setup_slub_min_order);
+__setup_param("slub_min_order=", slub_min_order, setup_slub_min_order, 0);
+
 
 static int __init setup_slub_max_order(char *str)
 {
@@ -5326,7 +5329,8 @@ static int __init setup_slub_max_order(char *str)
 	return 1;
 }
 
-__setup("slub_max_order=", setup_slub_max_order);
+__setup("slab_max_order=", setup_slub_max_order);
+__setup_param("slub_max_order=", slub_max_order, setup_slub_max_order, 0);
 
 static int __init setup_slub_min_objects(char *str)
 {
@@ -5335,7 +5339,8 @@ static int __init setup_slub_min_objects(char *str)
 	return 1;
 }
 
-__setup("slub_min_objects=", setup_slub_min_objects);
+__setup("slab_min_objects=", setup_slub_min_objects);
+__setup_param("slub_min_objects=", slub_min_objects, setup_slub_min_objects, 0);
 
 #ifdef CONFIG_HARDENED_USERCOPY
 /*