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authorPekka Enberg <penberg@cs.helsinki.fi>2007-05-06 14:48:40 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:12:50 -0700
commitfd76bab2fa6d8f3ef6b326a4c6ae442fa21d30a4 (patch)
tree66f310ab9d7cdadfb79486700f1e01df7923ec14 /mm/slab.c
parente3ebadd95cb621e2c7436f3d3646447ac9d5c16d (diff)
downloadlwn-fd76bab2fa6d8f3ef6b326a4c6ae442fa21d30a4.tar.gz
lwn-fd76bab2fa6d8f3ef6b326a4c6ae442fa21d30a4.zip
slab: introduce krealloc
This introduce krealloc() that reallocates memory while keeping the contents unchanged. The allocator avoids reallocation if the new size fits the currently used cache. I also added a simple non-optimized version for mm/slob.c for compatibility. [akpm@linux-foundation.org: fix warnings] Acked-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu> Acked-by: Matt Mackall <mpm@selenic.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r--mm/slab.c49
1 files changed, 48 insertions, 1 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 168bfe9d8ffe..8b71a9c3daa4 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3740,6 +3740,53 @@ EXPORT_SYMBOL(__kmalloc);
#endif
/**
+ * krealloc - reallocate memory. The contents will remain unchanged.
+ *
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * The contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes. If @p is %NULL, krealloc()
+ * behaves exactly like kmalloc(). If @size is 0 and @p is not a
+ * %NULL pointer, the object pointed to is freed.
+ */
+void *krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+ struct kmem_cache *cache, *new_cache;
+ void *ret;
+
+ if (unlikely(!p))
+ return kmalloc_track_caller(new_size, flags);
+
+ if (unlikely(!new_size)) {
+ kfree(p);
+ return NULL;
+ }
+
+ cache = virt_to_cache(p);
+ new_cache = __find_general_cachep(new_size, flags);
+
+ /*
+ * If new size fits in the current cache, bail out.
+ */
+ if (likely(cache == new_cache))
+ return (void *)p;
+
+ /*
+ * We are on the slow-path here so do not use __cache_alloc
+ * because it bloats kernel text.
+ */
+ ret = kmalloc_track_caller(new_size, flags);
+ if (ret) {
+ memcpy(ret, p, min(new_size, ksize(p)));
+ kfree(p);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(krealloc);
+
+/**
* kmem_cache_free - Deallocate an object
* @cachep: The cache the allocation was from.
* @objp: The previously allocated object.
@@ -4481,7 +4528,7 @@ const struct seq_operations slabstats_op = {
* allocated with either kmalloc() or kmem_cache_alloc(). The object
* must not be freed during the duration of the call.
*/
-unsigned int ksize(const void *objp)
+size_t ksize(const void *objp)
{
if (unlikely(objp == NULL))
return 0;