Miao Xie
2010-Mar-25 12:30 UTC
[PATCH 05/18] btrfs: Take num_copies out of loop for btree_read_extent_buffer_pages()
From: Zhao Lei <zhaolei@cn.fujitsu.com>
num_copies''s value is not changed in this function,
and it is not necessary to calculate its value multi-times.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
fs/btrfs/disk-io.c | 5 ++---
1 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 11d0ad3..79d9196 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -301,7 +301,8 @@ static int btree_read_extent_buffer_pages(struct btrfs_root
*root,
{
struct extent_io_tree *io_tree;
int ret;
- int num_copies = 0;
+ int num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
+ eb->start, eb->len);
int mirror_num = 0;
io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
@@ -312,8 +313,6 @@ static int btree_read_extent_buffer_pages(struct btrfs_root
*root,
!verify_parent_transid(io_tree, eb, parent_transid))
return ret;
- num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
- eb->start, eb->len);
if (num_copies == 1)
return ret;
--
1.6.5.2
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Chris Mason
2010-Mar-31 00:23 UTC
Re: [PATCH 05/18] btrfs: Take num_copies out of loop for btree_read_extent_buffer_pages()
On Thu, Mar 25, 2010 at 08:30:17PM +0800, Miao Xie wrote:> From: Zhao Lei <zhaolei@cn.fujitsu.com> > > num_copies''s value is not changed in this function, > and it is not necessary to calculate its value multi-times.It is true that we don''t need to calculate this multiple times, but with the existing code the calculation is only done when there is an IO error. We could use a check for num_copies == 0 before calling the calc function. -chris> > Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> > Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> > --- > fs/btrfs/disk-io.c | 5 ++--- > 1 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > index 11d0ad3..79d9196 100644 > --- a/fs/btrfs/disk-io.c > +++ b/fs/btrfs/disk-io.c > @@ -301,7 +301,8 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root, > { > struct extent_io_tree *io_tree; > int ret; > - int num_copies = 0; > + int num_copies = btrfs_num_copies(&root->fs_info->mapping_tree, > + eb->start, eb->len); > int mirror_num = 0; > > io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree; > @@ -312,8 +313,6 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root, > !verify_parent_transid(io_tree, eb, parent_transid)) > return ret; > > - num_copies = btrfs_num_copies(&root->fs_info->mapping_tree, > - eb->start, eb->len); > if (num_copies == 1) > return ret; > > -- > 1.6.5.2 > > > -- > 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-- 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
Zhaolei
2010-Mar-31 04:04 UTC
Re: Re: [PATCH 05/18] btrfs: Take num_copies out of loop for btree_read_extent_buffer_pages()
Chris Mason wrote:> On Thu, Mar 25, 2010 at 08:30:17PM +0800, Miao Xie wrote: >> From: Zhao Lei <zhaolei@cn.fujitsu.com> >> >> num_copies''s value is not changed in this function, >> and it is not necessary to calculate its value multi-times. > > It is true that we don''t need to calculate this multiple times, but with > the existing code the calculation is only done when there is an IO > error. > > We could use a check for num_copies == 0 before calling the calc > function. > > -chrisHello, chris I''ll modify this patch to read num_copies only in IO error. Thanks Zhaolei>> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> >> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> >> --- >> fs/btrfs/disk-io.c | 5 ++--- >> 1 files changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c >> index 11d0ad3..79d9196 100644 >> --- a/fs/btrfs/disk-io.c >> +++ b/fs/btrfs/disk-io.c >> @@ -301,7 +301,8 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root, >> { >> struct extent_io_tree *io_tree; >> int ret; >> - int num_copies = 0; >> + int num_copies = btrfs_num_copies(&root->fs_info->mapping_tree, >> + eb->start, eb->len); >> int mirror_num = 0; >> >> io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree; >> @@ -312,8 +313,6 @@ static int btree_read_extent_buffer_pages(struct btrfs_root *root, >> !verify_parent_transid(io_tree, eb, parent_transid)) >> return ret; >> >> - num_copies = btrfs_num_copies(&root->fs_info->mapping_tree, >> - eb->start, eb->len); >> if (num_copies == 1) >> return ret; >> >> -- >> 1.6.5.2 >> >> >> -- >> 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 > -- > 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 >-- 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