From 001e4a8775f6e8ad52a89e0072f09aee47d5d252 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 21 Jul 2015 23:51:26 -0400 Subject: [PATCH] ext4: implement cgroup writeback support For ordered and writeback data modes, all data IOs go through ext4_io_submit. This patch adds cgroup writeback support by invoking wbc_init_bio() from io_submit_init_bio() and wbc_account_io() in io_submit_add_bh(). Journal data which is written by jbd2 worker is left alone by this patch and will always be written out from the root cgroup. ext4_fill_super() is updated to set MS_CGROUPWB when data mode is either ordered or writeback. In journaled data mode, most IOs become synchronous through the journal and enabling cgroup writeback support doesn't make much sense or difference. Journaled data mode is left alone. Lightly tested with sequential data write workload. Behaves as expected. Signed-off-by: Tejun Heo Signed-off-by: Theodore Ts'o --- fs/ext4/page-io.c | 2 ++ fs/ext4/super.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c index a917bfe3e70c..58ab2e3dd114 100644 --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -383,6 +383,7 @@ static int io_submit_init_bio(struct ext4_io_submit *io, bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES)); if (!bio) return -ENOMEM; + wbc_init_bio(io->io_wbc, bio); bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); bio->bi_bdev = bh->b_bdev; bio->bi_end_io = ext4_end_bio; @@ -411,6 +412,7 @@ submit_and_retry: ret = bio_add_page(io->io_bio, page, bh->b_size, bh_offset(bh)); if (ret != bh->b_size) goto submit_and_retry; + wbc_account_io(io->io_wbc, page, bh->b_size); io->io_next_block++; return 0; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 58987b5c514b..d2c9a7985fd7 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3643,6 +3643,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) } if (test_opt(sb, DELALLOC)) clear_opt(sb, DELALLOC); + } else { + sb->s_iflags |= SB_I_CGROUPWB; } sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |