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Subject[PATCH 04/13] Fix ridr_alloc_layer()
[PATCH 04/13]

This patch only fixes the alloc_layer() portion of ridr.c, to make it use the
per-cpu pool of preloaded ridr layer structures.

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>

---
lib/ridr.c | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)

Index: linux-2.6.25-rc8-mm1/lib/ridr.c
===================================================================
--- linux-2.6.25-rc8-mm1.orig/lib/ridr.c 2008-04-11 17:40:13.000000000 +0200
+++ linux-2.6.25-rc8-mm1/lib/ridr.c 2008-04-11 17:43:44.000000000 +0200
@@ -22,20 +22,35 @@ struct ridr_preget {
};
DEFINE_PER_CPU(struct ridr_preget, ridr_pregets) = { 0, };

+static inline gfp_t ridr_gfp_mask(struct ridr *idp)
+{
+ return idp->gfp_mask & __GFP_BITS_MASK;
+}
+
static struct ridr_layer *alloc_layer(struct ridr *idp)
{
- struct ridr_layer *p;
- unsigned long flags;
+ struct ridr_layer *ret = NULL;
+ gfp_t gfp_mask = ridr_gfp_mask(idp);

- spin_lock_irqsave(&idp->lock, flags);
- p = idp->id_free;
- if (p) {
- idp->id_free = p->ary[0];
- idp->id_free_cnt--;
- p->ary[0] = NULL;
+ if (!(gfp_mask & __GFP_WAIT)) {
+ struct ridr_preget *ridp;
+
+ /*
+ * Provided the caller has preloaded here, we will always
+ * succeed in getting a node here (and never reach
+ * kmem_cache_alloc)
+ */
+ ridp = &__get_cpu_var(ridr_pregets);
+ if (ridp->nr) {
+ ret = ridp->layers[ridp->nr - 1];
+ ridp->layers[ridp->nr - 1] = NULL;
+ ridp->nr--;
+ }
}
- spin_unlock_irqrestore(&idp->lock, flags);
- return(p);
+ if (ret == NULL)
+ ret = kmem_cache_alloc(ridr_layer_cache, gfp_mask);
+
+ return ret;
}

/* only called when idp->lock is held */
--


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