Ilya Dryomov
2011-Jan-19 15:34 UTC
[PATCH] Btrfs: remove unneeded allocation in load_free_space_cache()
The checksums array is unused, remove it. We only need disk_crcs array
to verify checksums.
There is no need to allocate first_page_offset bytes for disk_crcs
array. It''s enough to allocate num_checksums bytes because disk_crcs
only holds checksums while gen pointer is computed and used
independently.
cur_crc is initialized later in the code. Don''t initialize it in a
declaration.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
fs/btrfs/free-space-cache.c | 12 ++++--------
1 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 60d6842..258e45d 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -215,14 +215,14 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
struct extent_buffer *leaf;
struct page *page;
struct btrfs_path *path;
- u32 *checksums = NULL, *crc;
+ u32 *crc = NULL;
char *disk_crcs = NULL;
struct btrfs_key key;
struct list_head bitmaps;
u64 num_entries;
u64 num_bitmaps;
u64 generation;
- u32 cur_crc = ~(u32)0;
+ u32 cur_crc;
pgoff_t index = 0;
unsigned long first_page_offset;
int num_checksums;
@@ -298,11 +298,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
/* Setup everything for doing checksumming */
num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
- checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
- if (!checksums)
- goto out;
first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
- disk_crcs = kzalloc(first_page_offset, GFP_NOFS);
+ disk_crcs = kzalloc(num_checksums, GFP_NOFS);
if (!disk_crcs)
goto out;
@@ -352,7 +349,7 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
if (index == 0) {
u64 *gen;
- memcpy(disk_crcs, addr, first_page_offset);
+ memcpy(disk_crcs, addr, num_checksums);
gen = addr + (sizeof(u32) * num_checksums);
if (*gen != BTRFS_I(inode)->generation) {
printk(KERN_ERR "btrfs: space cache generation"
@@ -467,7 +464,6 @@ next:
ret = 1;
out:
- kfree(checksums);
kfree(disk_crcs);
iput(inode);
return ret;
--
1.7.2.3
Ilya Dryomov
2011-Jan-19 16:58 UTC
[PATCH v2] Btrfs: remove unneeded allocation in load_free_space_cache()
I messed up size argument of kzalloc() and consequently memcpy(). Here
is an updated version.
The checksums array is unused, remove it. We only need disk_crcs array
to verify checksums.
There is no need to allocate first_page_offset bytes for disk_crcs
array. It''s enough to allocate (sizeof(u32) * num_checksums) bytes
because disk_crcs should only hold checksums. gen is fetched
directly from the page.
cur_crc is initialized later in the code. Don''t initialize it in a
declaration.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
---
fs/btrfs/free-space-cache.c | 12 ++++--------
1 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 60d6842..ee0af41 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -215,14 +215,14 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
struct extent_buffer *leaf;
struct page *page;
struct btrfs_path *path;
- u32 *checksums = NULL, *crc;
+ u32 *crc = NULL;
char *disk_crcs = NULL;
struct btrfs_key key;
struct list_head bitmaps;
u64 num_entries;
u64 num_bitmaps;
u64 generation;
- u32 cur_crc = ~(u32)0;
+ u32 cur_crc;
pgoff_t index = 0;
unsigned long first_page_offset;
int num_checksums;
@@ -298,11 +298,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
/* Setup everything for doing checksumming */
num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
- checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
- if (!checksums)
- goto out;
first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
- disk_crcs = kzalloc(first_page_offset, GFP_NOFS);
+ disk_crcs = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
if (!disk_crcs)
goto out;
@@ -352,7 +349,7 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info,
if (index == 0) {
u64 *gen;
- memcpy(disk_crcs, addr, first_page_offset);
+ memcpy(disk_crcs, addr, sizeof(u32) * num_checksums);
gen = addr + (sizeof(u32) * num_checksums);
if (*gen != BTRFS_I(inode)->generation) {
printk(KERN_ERR "btrfs: space cache generation"
@@ -467,7 +464,6 @@ next:
ret = 1;
out:
- kfree(checksums);
kfree(disk_crcs);
iput(inode);
return ret;
--
1.7.2.3
Josef Bacik
2011-Jan-19 18:51 UTC
Re: [PATCH v2] Btrfs: remove unneeded allocation in load_free_space_cache()
On Wed, Jan 19, 2011 at 06:58:37PM +0200, Ilya Dryomov wrote:> I messed up size argument of kzalloc() and consequently memcpy(). Here > is an updated version. > > > The checksums array is unused, remove it. We only need disk_crcs array > to verify checksums. > > There is no need to allocate first_page_offset bytes for disk_crcs > array. It''s enough to allocate (sizeof(u32) * num_checksums) bytes > because disk_crcs should only hold checksums. gen is fetched > directly from the page. > > cur_crc is initialized later in the code. Don''t initialize it in a > declaration. > > Signed-off-by: Ilya Dryomov <idryomov@gmail.com>Reviewed-by: Josef Bacik <josef@redhat.com> Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html