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Date: Fri, 26 Feb 2016 15:01:18 +0900
From: js1304@...il.com
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Christoph Lameter <cl@...ux.com>,
Pekka Enberg <penberg@...nel.org>,
David Rientjes <rientjes@...gle.com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Vlastimil Babka <vbabka@...e.cz>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, Joonsoo Kim <iamjoonsoo.kim@....com>
Subject: [PATCH v2 11/17] mm/slab: clean up cache type determination
From: Joonsoo Kim <iamjoonsoo.kim@....com>
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@....com>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Pekka Enberg <penberg@...nel.org>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Jesper Dangaard Brouer <brouer@...hat.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
mm/slab.c | 105 ++++++++++++++++++++++++++++++++++++++++++--------------------
1 file changed, 71 insertions(+), 34 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index d5dffc8..9b56685 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2023,6 +2023,64 @@ __kmem_cache_alias(const char *name, size_t size, size_t align,
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
@@ -2047,7 +2105,6 @@ __kmem_cache_alias(const char *name, size_t size, size_t align,
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;
@@ -2098,6 +2155,10 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
* 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;
@@ -2152,43 +2213,18 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
}
#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))
@@ -2209,7 +2245,8 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
#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
--
1.9.1
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