direct-io: use a slab cache for struct dio

[~andy/linux] / fs / direct-io.c

diff --git a/fs/direct-io.c b/fs/direct-io.c
index b01ea0d7160dc30fbf5448fae09ab6963562091d..6bb04409e7257fdde3e870b02de2cc7ef1850b52 100644 (file)
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -140,7 +140,9 @@ struct dio {
         * wish that they not be zeroed.
         */
        struct page *pages[DIO_PAGES];  /* page buffer */
-};
+} ____cacheline_aligned_in_smp;
+
+static struct kmem_cache *dio_cache __read_mostly;
 
 static void __inode_dio_wait(struct inode *inode)
 {
@@ -330,7 +332,7 @@ static void dio_bio_end_aio(struct bio *bio, int error)
 
        if (remaining == 0) {
                dio_complete(dio, dio->iocb->ki_pos, 0, true);
-               kfree(dio);
+               kmem_cache_free(dio_cache, dio);
        }
 }
 
@@ -1180,7 +1182,7 @@ direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
 
        if (ret2 == 0) {
                ret = dio_complete(dio, offset, ret, false);
-               kfree(dio);
+               kmem_cache_free(dio_cache, dio);
        } else
                BUG_ON(ret != -EIOCBQUEUED);
 
@@ -1256,7 +1258,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
        if (rw == READ && end == offset)
                return 0;
 
-       dio = kmalloc(sizeof(*dio), GFP_KERNEL);
+       dio = kmem_cache_alloc(dio_cache, GFP_KERNEL);
        retval = -ENOMEM;
        if (!dio)
                goto out;
@@ -1280,7 +1282,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
                                                              end - 1);
                        if (retval) {
                                mutex_unlock(&inode->i_mutex);
-                               kfree(dio);
+                               kmem_cache_free(dio_cache, dio);
                                goto out;
                        }
                }
@@ -1308,3 +1310,10 @@ out:
        return retval;
 }
 EXPORT_SYMBOL(__blockdev_direct_IO);
+
+static __init int dio_init(void)
+{
+       dio_cache = KMEM_CACHE(dio, SLAB_PANIC);
+       return 0;
+}
+module_init(dio_init)