| Message ID | 20190822082617.19180-1-dongyangli@ddn.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/4] libext2fs: optimize ext2fs_convert_subcluster_bitmap() | expand |
On Aug 22, 2019, at 2:26 AM, Dongyang Li <dongyangli@ddn.com> wrote: > > For a bigalloc filesystem, converting the block bitmap from blocks > to chunks in ext2fs_convert_subcluster_bitmap() can take a long time > when the device is huge, because we test the bitmap > bit-by-bit using ext2fs_test_block_bitmap2(). > Use ext2fs_find_first_set_block_bitmap2() which is more efficient > for mke2fs when the fs is mostly empty. > > e2fsck can also benefit from this during pass1 block scanning. > > Time taken for "mke2fs -O bigalloc,extent -C 131072 -b 4096" on a 1PB > device: > > without patch: > real 27m49.457s > user 21m36.474s > sys 6m9.514s > > with patch: > real 6m31.908s > user 0m1.806s > sys 6m29.697s > > Signed-off-by: Li Dongyang <dongyangli@ddn.com> Reviewed-by: Andreas Dilger <adilger@dilger.ca> > --- > lib/ext2fs/gen_bitmap64.c | 20 +++++++------------- > 1 file changed, 7 insertions(+), 13 deletions(-) > > diff --git a/lib/ext2fs/gen_bitmap64.c b/lib/ext2fs/gen_bitmap64.c > index 6e4d8b71..f1dd1891 100644 > --- a/lib/ext2fs/gen_bitmap64.c > +++ b/lib/ext2fs/gen_bitmap64.c > @@ -799,8 +799,7 @@ errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs, > ext2fs_generic_bitmap_64 bmap, cmap; > ext2fs_block_bitmap gen_bmap = *bitmap, gen_cmap; > errcode_t retval; > - blk64_t i, b_end, c_end; > - int n, ratio; > + blk64_t i, next, b_end, c_end; > > bmap = (ext2fs_generic_bitmap_64) gen_bmap; > if (fs->cluster_ratio_bits == ext2fs_get_bitmap_granularity(gen_bmap)) > @@ -817,18 +816,13 @@ errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs, > bmap->end = bmap->real_end; > c_end = cmap->end; > cmap->end = cmap->real_end; > - n = 0; > - ratio = 1 << fs->cluster_ratio_bits; > while (i < bmap->real_end) { > - if (ext2fs_test_block_bitmap2(gen_bmap, i)) { > - ext2fs_mark_block_bitmap2(gen_cmap, i); > - i += ratio - n; > - n = 0; > - continue; > - } > - i++; n++; > - if (n >= ratio) > - n = 0; > + retval = ext2fs_find_first_set_block_bitmap2(gen_bmap, > + i, bmap->real_end, &next); > + if (retval) > + break; > + ext2fs_mark_block_bitmap2(gen_cmap, next); > + i = EXT2FS_C2B(fs, EXT2FS_B2C(fs, next) + 1); > } > bmap->end = b_end; > cmap->end = c_end; > -- > 2.22.1 > Cheers, Andreas
diff --git a/lib/ext2fs/gen_bitmap64.c b/lib/ext2fs/gen_bitmap64.c index 6e4d8b71..f1dd1891 100644 --- a/lib/ext2fs/gen_bitmap64.c +++ b/lib/ext2fs/gen_bitmap64.c @@ -799,8 +799,7 @@ errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs, ext2fs_generic_bitmap_64 bmap, cmap; ext2fs_block_bitmap gen_bmap = *bitmap, gen_cmap; errcode_t retval; - blk64_t i, b_end, c_end; - int n, ratio; + blk64_t i, next, b_end, c_end; bmap = (ext2fs_generic_bitmap_64) gen_bmap; if (fs->cluster_ratio_bits == ext2fs_get_bitmap_granularity(gen_bmap)) @@ -817,18 +816,13 @@ errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs, bmap->end = bmap->real_end; c_end = cmap->end; cmap->end = cmap->real_end; - n = 0; - ratio = 1 << fs->cluster_ratio_bits; while (i < bmap->real_end) { - if (ext2fs_test_block_bitmap2(gen_bmap, i)) { - ext2fs_mark_block_bitmap2(gen_cmap, i); - i += ratio - n; - n = 0; - continue; - } - i++; n++; - if (n >= ratio) - n = 0; + retval = ext2fs_find_first_set_block_bitmap2(gen_bmap, + i, bmap->real_end, &next); + if (retval) + break; + ext2fs_mark_block_bitmap2(gen_cmap, next); + i = EXT2FS_C2B(fs, EXT2FS_B2C(fs, next) + 1); } bmap->end = b_end; cmap->end = c_end;
For a bigalloc filesystem, converting the block bitmap from blocks to chunks in ext2fs_convert_subcluster_bitmap() can take a long time when the device is huge, because we test the bitmap bit-by-bit using ext2fs_test_block_bitmap2(). Use ext2fs_find_first_set_block_bitmap2() which is more efficient for mke2fs when the fs is mostly empty. e2fsck can also benefit from this during pass1 block scanning. Time taken for "mke2fs -O bigalloc,extent -C 131072 -b 4096" on a 1PB device: without patch: real 27m49.457s user 21m36.474s sys 6m9.514s with patch: real 6m31.908s user 0m1.806s sys 6m29.697s Signed-off-by: Li Dongyang <dongyangli@ddn.com> --- lib/ext2fs/gen_bitmap64.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)