The patch titled
Subject: mm/slab: clean up cache type determination
has been added to the -mm tree. Its filename is
mm-slab-clean-up-cache-type-determination.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slab-clean-up-cache-type-determination.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-clean-up-cache-type-determination.patch
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------------------------------------------------------
From: Joonsoo Kim <js1304@xxxxxxxxx>
Subject: mm/slab: clean up cache type determination
Current cache type determination code is open-code and looks not
understandable. Following patch will introduce one more cache type and it
would make code more complex. So, before it happens, this patch abstracts
these codes.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 105 +++++++++++++++++++++++++++++++++++-----------------
1 file changed, 71 insertions(+), 34 deletions(-)
diff -puN mm/slab.c~mm-slab-clean-up-cache-type-determination mm/slab.c
--- a/mm/slab.c~mm-slab-clean-up-cache-type-determination
+++ a/mm/slab.c
@@ -2024,6 +2024,64 @@ __kmem_cache_alias(const char *name, siz
return cachep;
}
+static bool set_off_slab_cache(struct kmem_cache *cachep,
+ size_t size, unsigned long flags)
+{
+ size_t left;
+
+ cachep->num = 0;
+
+ /*
+ * Determine if the slab management is 'on' or 'off' slab.
+ * (bootstrapping cannot cope with offslab caches so don't do
+ * it too early on. Always use on-slab management when
+ * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
+ */
+ if (size < OFF_SLAB_MIN_SIZE)
+ return false;
+
+ if (slab_early_init)
+ return false;
+
+ if (flags & SLAB_NOLEAKTRACE)
+ return false;
+
+ /*
+ * Size is large, assume best to place the slab management obj
+ * off-slab (should allow better packing of objs).
+ */
+ left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB);
+ if (!cachep->num)
+ return false;
+
+ /*
+ * If the slab has been placed off-slab, and we have enough space then
+ * move it on-slab. This is at the expense of any extra colouring.
+ */
+ if (left >= cachep->num * sizeof(freelist_idx_t))
+ return false;
+
+ cachep->colour = left / cachep->colour_off;
+
+ return true;
+}
+
+static bool set_on_slab_cache(struct kmem_cache *cachep,
+ size_t size, unsigned long flags)
+{
+ size_t left;
+
+ cachep->num = 0;
+
+ left = calculate_slab_order(cachep, size, flags);
+ if (!cachep->num)
+ return false;
+
+ cachep->colour = left / cachep->colour_off;
+
+ return true;
+}
+
/**
* __kmem_cache_create - Create a cache.
* @cachep: cache management descriptor
@@ -2048,7 +2106,6 @@ __kmem_cache_alias(const char *name, siz
int
__kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
{
- size_t left_over, freelist_size;
size_t ralign = BYTES_PER_WORD;
gfp_t gfp;
int err;
@@ -2099,6 +2156,10 @@ __kmem_cache_create (struct kmem_cache *
* 4) Store it.
*/
cachep->align = ralign;
+ cachep->colour_off = cache_line_size();
+ /* Offset must be a multiple of the alignment. */
+ if (cachep->colour_off < cachep->align)
+ cachep->colour_off = cachep->align;
if (slab_is_available())
gfp = GFP_KERNEL;
@@ -2153,43 +2214,18 @@ __kmem_cache_create (struct kmem_cache *
}
#endif
- /*
- * Determine if the slab management is 'on' or 'off' slab.
- * (bootstrapping cannot cope with offslab caches so don't do
- * it too early on. Always use on-slab management when
- * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
- */
- if (size >= OFF_SLAB_MIN_SIZE && !slab_early_init &&
- !(flags & SLAB_NOLEAKTRACE)) {
- /*
- * Size is large, assume best to place the slab management obj
- * off-slab (should allow better packing of objs).
- */
+ if (set_off_slab_cache(cachep, size, flags)) {
flags |= CFLGS_OFF_SLAB;
+ goto done;
}
- left_over = calculate_slab_order(cachep, size, flags);
-
- if (!cachep->num)
- return -E2BIG;
-
- freelist_size = cachep->num * sizeof(freelist_idx_t);
+ if (set_on_slab_cache(cachep, size, flags))
+ goto done;
- /*
- * If the slab has been placed off-slab, and we have enough space then
- * move it on-slab. This is at the expense of any extra colouring.
- */
- if (flags & CFLGS_OFF_SLAB && left_over >= freelist_size) {
- flags &= ~CFLGS_OFF_SLAB;
- left_over -= freelist_size;
- }
+ return -E2BIG;
- cachep->colour_off = cache_line_size();
- /* Offset must be a multiple of the alignment. */
- if (cachep->colour_off < cachep->align)
- cachep->colour_off = cachep->align;
- cachep->colour = left_over / cachep->colour_off;
- cachep->freelist_size = freelist_size;
+done:
+ cachep->freelist_size = cachep->num * sizeof(freelist_idx_t);
cachep->flags = flags;
cachep->allocflags = __GFP_COMP;
if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
@@ -2210,7 +2246,8 @@ __kmem_cache_create (struct kmem_cache *
#endif
if (OFF_SLAB(cachep)) {
- cachep->freelist_cache = kmalloc_slab(freelist_size, 0u);
+ cachep->freelist_cache =
+ kmalloc_slab(cachep->freelist_size, 0u);
/*
* This is a possibility for one of the kmalloc_{dma,}_caches.
* But since we go off slab only for object size greater than
_
Patches currently in -mm which might be from js1304@xxxxxxxxx are
mm-slab-fix-stale-code-comment.patch
mm-slab-remove-useless-structure-define.patch
mm-slab-remove-the-checks-for-slab-implementation-bug.patch
mm-slab-activate-debug_pagealloc-in-slab-when-it-is-actually-enabled.patch
mm-slab-use-more-appropriate-condition-check-for-debug_pagealloc.patch
mm-slab-clean-up-debug_pagealloc-processing-code.patch
mm-slab-alternative-implementation-for-debug_slab_leak.patch
mm-slab-remove-object-status-buffer-for-debug_slab_leak.patch
mm-slab-put-the-freelist-at-the-end-of-slab-page.patch
mm-slab-align-cache-size-first-before-determination-of-off_slab-candidate.patch
mm-slab-clean-up-cache-type-determination.patch
mm-slab-do-not-change-cache-size-if-debug-pagealloc-isnt-possible.patch
mm-slab-make-criteria-for-off-slab-determination-robust-and-simple.patch
mm-slab-factor-out-slab-list-fixup-code.patch
mm-slab-factor-out-debugging-initialization-in-cache_init_objs.patch
mm-slab-introduce-new-slab-management-type-objfreelist_slab.patch
--
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