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authorEric Sandeen <sandeen@redhat.com>2010-12-07 11:51:05 -0600
committerJan Kara <jack@suse.cz>2011-01-10 19:04:06 +0100
commit40a063f6691ce937a3d00c9700b6964b5ec4e022 (patch)
tree2726e4d6b5716edb3a1124a3c7a4ba1348d84b69
parent156e74312f1ffc0a2639c24c771c5a0e106f0505 (diff)
ext2: speed up file creates by optimizing rec_len functions
The addition of 64k block capability in the rec_len_from_disk and rec_len_to_disk functions added a bit of math overhead which slows down file create workloads needlessly when the architecture cannot even support 64k blocks, thanks to page size limits. The directory entry checking can also be optimized a bit by sprinkling in some unlikely() conditions to move the error handling out of line. bonnie++ sequential file creates on a 512MB ramdisk speeds up from about 2200/s to about 2500/s, about a 14% improvement. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/ext2/dir.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 2709b34206ab..47cda410b548 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -28,21 +28,30 @@
typedef struct ext2_dir_entry_2 ext2_dirent;
+/*
+ * Tests against MAX_REC_LEN etc were put in place for 64k block
+ * sizes; if that is not possible on this arch, we can skip
+ * those tests and speed things up.
+ */
static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
{
unsigned len = le16_to_cpu(dlen);
+#if (PAGE_CACHE_SIZE >= 65536)
if (len == EXT2_MAX_REC_LEN)
return 1 << 16;
+#endif
return len;
}
static inline __le16 ext2_rec_len_to_disk(unsigned len)
{
+#if (PAGE_CACHE_SIZE >= 65536)
if (len == (1 << 16))
return cpu_to_le16(EXT2_MAX_REC_LEN);
else
BUG_ON(len > (1 << 16));
+#endif
return cpu_to_le16(len);
}
@@ -129,15 +138,15 @@ static void ext2_check_page(struct page *page, int quiet)
p = (ext2_dirent *)(kaddr + offs);
rec_len = ext2_rec_len_from_disk(p->rec_len);
- if (rec_len < EXT2_DIR_REC_LEN(1))
+ if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
goto Eshort;
- if (rec_len & 3)
+ if (unlikely(rec_len & 3))
goto Ealign;
- if (rec_len < EXT2_DIR_REC_LEN(p->name_len))
+ if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
goto Enamelen;
- if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
+ if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
goto Espan;
- if (le32_to_cpu(p->inode) > max_inumber)
+ if (unlikely(le32_to_cpu(p->inode) > max_inumber))
goto Einumber;
}
if (offs != limit)