From: Jaegeuk Kim <jaegeuk@kernel.org>
To: NeilBrown <neilb@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Chao Yu <chao@kernel.org>, Jeff Layton <jlayton@kernel.org>,
Ilya Dryomov <idryomov@gmail.com>,
Miklos Szeredi <miklos@szeredi.hu>,
Trond Myklebust <trond.myklebust@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Ryusuke Konishi <konishi.ryusuke@gmail.com>,
"Darrick J. Wong" <djwong@kernel.org>,
Philipp Reisner <philipp.reisner@linbit.com>,
Lars Ellenberg <lars.ellenberg@linbit.com>,
Paolo Valente <paolo.valente@linaro.org>,
Jens Axboe <axboe@kernel.dk>,
linux-mm@kvack.org, linux-nilfs@vger.kernel.org,
linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net,
linux-ext4@vger.kernel.org, ceph-devel@vger.kernel.org,
drbd-dev@lists.linbit.com, linux-kernel@vger.kernel.org,
linux-block@vger.kernel.org
Subject: Re: [PATCH 3/9] f2fs: change retry waiting for f2fs_write_single_data_page()
Date: Thu, 27 Jan 2022 17:34:31 -0800 [thread overview]
Message-ID: <YfNIJxirDBO/pcQQ@google.com> (raw)
In-Reply-To: <164325158956.29787.7016948342209980097.stgit@noble.brown>
On 01/27, NeilBrown wrote:
> f2fs_write_single_data_page() can return -EAGAIN if it cannot get
> the cp_rwsem lock - it holds a page lock and so cannot wait for it.
>
> Some code which calls f2fs_write_single_data_page() use
> congestion_wait() and then tries again. congestion_wait() doesn't do
> anything useful as congestion is no longer tracked. So this is just a
> simple sleep.
>
> A better approach is it wait until the cp_rwsem lock can be taken - then
> try again. There is certainly no point trying again *before* the lock
> can be taken.
>
> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
> fs/f2fs/compress.c | 6 +++---
> fs/f2fs/data.c | 9 ++++++---
> 2 files changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index d0c3aeba5945..58ff7f4b296c 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -1505,9 +1505,9 @@ static int f2fs_write_raw_pages(struct compress_ctx *cc,
> if (IS_NOQUOTA(cc->inode))
> return 0;
> ret = 0;
> - cond_resched();
> - congestion_wait(BLK_RW_ASYNC,
> - DEFAULT_IO_TIMEOUT);
> + /* Wait until we can get the lock, then try again. */
> + f2fs_lock_op(F2FS_I_SB(cc->inode));
> + f2fs_unlock_op(F2FS_I_SB(cc->inode));
Since checkpoint uses down_write(cp_rwsem), I'm not sure the write path is safe
and needs to wait for checkpoint. Can we just do io_schedule_timeout()?
> goto retry_write;
> }
> return ret;
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 8c417864c66a..1d2341163e2c 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3047,9 +3047,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> } else if (ret == -EAGAIN) {
> ret = 0;
> if (wbc->sync_mode == WB_SYNC_ALL) {
> - cond_resched();
> - congestion_wait(BLK_RW_ASYNC,
> - DEFAULT_IO_TIMEOUT);
> + /* Wait until we can get the
> + * lock, then try again.
> + */
> + f2fs_lock_op(F2FS_I_SB(mapping->host));
> + f2fs_unlock_op(F2FS_I_SB(mapping->host));
> +
> goto retry_write;
> }
> goto next;
>
next prev parent reply other threads:[~2022-01-28 1:34 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-27 2:46 [PATCH 0/9] Remove remaining parts of congestions tracking code NeilBrown
2022-01-27 2:46 ` [PATCH 2/9] Remove bdi_congested() and wb_congested() and related functions NeilBrown
2022-01-27 22:10 ` Ryusuke Konishi
2022-01-27 2:46 ` [PATCH 5/9] cephfs: don't set/clear bdi_congestion NeilBrown
2022-01-27 11:12 ` Jeff Layton
2022-01-27 2:46 ` [PATCH 9/9] Remove congestion tracking framework NeilBrown
2022-01-27 2:46 ` [PATCH 8/9] block/bfq-iosched.c: use "false" rather than "BLK_RW_ASYNC" NeilBrown
2022-01-27 2:46 ` [PATCH 1/9] Remove inode_congested() NeilBrown
2022-01-28 9:37 ` Miklos Szeredi
2022-01-28 21:36 ` NeilBrown
2022-01-27 2:46 ` [PATCH 6/9] fuse: don't set/clear bdi_congested NeilBrown
2022-01-27 2:46 ` [PATCH 3/9] f2fs: change retry waiting for f2fs_write_single_data_page() NeilBrown
2022-01-28 1:34 ` Jaegeuk Kim [this message]
2022-01-27 2:46 ` [PATCH 7/9] NFS: remove congestion control NeilBrown
2022-01-27 2:46 ` [PATCH 4/9] f2f2: replace some congestion_wait() calls with io_schedule_timeout() NeilBrown
2022-01-28 1:27 ` Jaegeuk Kim
2022-01-27 22:42 ` [PATCH 0/9] Remove remaining parts of congestions tracking code Andrew Morton
2022-01-28 0:58 ` Jens Axboe
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