| Message ID | 1309445439-3753-2-git-send-email-tm@tao.ma |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 2011-06-30, at 8:50 AM, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > When we trim some free blocks in a group of ext4, we should > calculate the free blocks properly and check whether there are > enough freed blocks left for us to trim. Current solution will > only calculate free spaces if they are large for a trim which > isn't appropriate. > > Let us see a small example: > a group has 1.5M free which are 300k, 300k, 300k, 300k, 300k. > And minblocks is 1M. With current solution, we have to iterate > the whole group since these 300k will never be subtracted from > 1.5M. But actually we should exit after we find the first 2 > free spaces since the left 3 chunks only sum up to 900K if we > subtract the first 600K although they can't be trimed. > > Signed-off-by: Tao Ma <boyu.mt@taobao.com> Reviewed-by: Andreas Dilger <adilger@dilger.ca> > --- > fs/ext4/mballoc.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 2336424..83fb04b 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -4823,7 +4823,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, > ext4_grpblk_t minblocks) > { > void *bitmap; > - ext4_grpblk_t next, count = 0; > + ext4_grpblk_t next, count = 0, free_count = 0; > struct ext4_buddy e4b; > int ret; > > @@ -4850,6 +4850,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, > next - start, group, &e4b); > count += next - start; > } > + free_count += next - start; > start = next + 1; > > if (fatal_signal_pending(current)) { > @@ -4863,7 +4864,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, > ext4_lock_group(sb, group); > } > > - if ((e4b.bd_info->bb_free - count) < minblocks) > + if ((e4b.bd_info->bb_free - free_count) < minblocks) > break; > } > ext4_unlock_group(sb, group); > -- > 1.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 30 Jun 2011, Tao Ma wrote: > From: Tao Ma <boyu.mt@taobao.com> > > When we trim some free blocks in a group of ext4, we should > calculate the free blocks properly and check whether there are > enough freed blocks left for us to trim. Current solution will > only calculate free spaces if they are large for a trim which > isn't appropriate. > > Let us see a small example: > a group has 1.5M free which are 300k, 300k, 300k, 300k, 300k. > And minblocks is 1M. With current solution, we have to iterate > the whole group since these 300k will never be subtracted from > 1.5M. But actually we should exit after we find the first 2 > free spaces since the left 3 chunks only sum up to 900K if we > subtract the first 600K although they can't be trimed. Looks good, thanks! -Lukas > > Signed-off-by: Tao Ma <boyu.mt@taobao.com> > --- > fs/ext4/mballoc.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 2336424..83fb04b 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -4823,7 +4823,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, > ext4_grpblk_t minblocks) > { > void *bitmap; > - ext4_grpblk_t next, count = 0; > + ext4_grpblk_t next, count = 0, free_count = 0; > struct ext4_buddy e4b; > int ret; > > @@ -4850,6 +4850,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, > next - start, group, &e4b); > count += next - start; > } > + free_count += next - start; > start = next + 1; > > if (fatal_signal_pending(current)) { > @@ -4863,7 +4864,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, > ext4_lock_group(sb, group); > } > > - if ((e4b.bd_info->bb_free - count) < minblocks) > + if ((e4b.bd_info->bb_free - free_count) < minblocks) > break; > } > ext4_unlock_group(sb, group); >
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 2336424..83fb04b 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4823,7 +4823,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, ext4_grpblk_t minblocks) { void *bitmap; - ext4_grpblk_t next, count = 0; + ext4_grpblk_t next, count = 0, free_count = 0; struct ext4_buddy e4b; int ret; @@ -4850,6 +4850,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, next - start, group, &e4b); count += next - start; } + free_count += next - start; start = next + 1; if (fatal_signal_pending(current)) { @@ -4863,7 +4864,7 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, ext4_lock_group(sb, group); } - if ((e4b.bd_info->bb_free - count) < minblocks) + if ((e4b.bd_info->bb_free - free_count) < minblocks) break; } ext4_unlock_group(sb, group);