From d7fbd893388d9e86d29b7cfbd5457bcf03496fbf Mon Sep 17 00:00:00 2001 From: Ajeet Yadav Date: Tue, 27 Dec 2011 15:10:04 +0530 Subject: [PATCH] Squashfs: optimise squashfs_cache_get entry search squashfs_cache_get() iterates over all entries to search for block its looking for. Often get() / put() are called for same block. If we cache the current entry index, then we can optimise the subsequent *_get() calls. Signed-off-by: Ajeet Yadav Signed-off-by: Phillip Lougher --- fs/squashfs/cache.c | 11 ++++++++--- fs/squashfs/squashfs_fs_sb.h | 1 + 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/squashfs/cache.c b/fs/squashfs/cache.c index ea6e798e548..af0b7380259 100644 --- a/fs/squashfs/cache.c +++ b/fs/squashfs/cache.c @@ -70,11 +70,15 @@ struct squashfs_cache_entry *squashfs_cache_get(struct super_block *sb, spin_lock(&cache->lock); while (1) { - for (i = 0; i < cache->entries; i++) - if (cache->entry[i].block == block) + for (i = cache->curr_blk, n = 0; n < cache->entries; n++) { + if (cache->entry[i].block == block) { + cache->curr_blk = i; break; + } + i = (i + 1) % cache->entries; + } - if (i == cache->entries) { + if (n == cache->entries) { /* * Block not in cache, if all cache entries are used * go to sleep waiting for one to become available. @@ -245,6 +249,7 @@ struct squashfs_cache *squashfs_cache_init(char *name, int entries, goto cleanup; } + cache->curr_blk = 0; cache->next_blk = 0; cache->unused = entries; cache->entries = entries; diff --git a/fs/squashfs/squashfs_fs_sb.h b/fs/squashfs/squashfs_fs_sb.h index 651f0b31d29..52934a22f29 100644 --- a/fs/squashfs/squashfs_fs_sb.h +++ b/fs/squashfs/squashfs_fs_sb.h @@ -28,6 +28,7 @@ struct squashfs_cache { char *name; int entries; + int curr_blk; int next_blk; int num_waiters; int unused;