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| author | Jens Axboe <axboe@kernel.dk> | 2023-03-07 19:47:20 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-04-03 16:14:20 +0300 |
| commit | d4755e15386c38e4ae532ace5acc29fbfaee42e7 (patch) | |
| tree | 1edc85467c3ea9ede5ee2d18b7021d3c0588f968 /io_uring | |
| parent | d8aeb44a9ae324c4b823689fabb30b6621d93c88 (diff) | |
| download | linux-d4755e15386c38e4ae532ace5acc29fbfaee42e7.tar.xz | |
io_uring: avoid hashing O_DIRECT writes if the filesystem doesn't need it
io_uring hashes writes to a given file/inode so that it can serialize
them. This is useful if the file system needs exclusive access to the
file to perform the write, as otherwise we end up with a ton of io-wq
threads trying to lock the inode at the same time. This can cause
excessive system time.
But if the file system has flagged that it supports parallel O_DIRECT
writes, then there's no need to serialize the writes. Check for that
through FMODE_DIO_PARALLEL_WRITE and don't hash it if we don't need to.
In a basic test of 8 threads writing to a file on XFS on a gen2 Optane,
with each thread writing in 4k chunks, it improves performance from
~1350K IOPS (or ~5290MiB/sec) to ~1410K IOPS (or ~5500MiB/sec).
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 722624b6d0dc..1ed96caa586a 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -425,7 +425,13 @@ static void io_prep_async_work(struct io_kiocb *req) req->flags |= io_file_get_flags(req->file) << REQ_F_SUPPORT_NOWAIT_BIT; if (req->flags & REQ_F_ISREG) { - if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL)) + bool should_hash = def->hash_reg_file; + + /* don't serialize this request if the fs doesn't need it */ + if (should_hash && (req->file->f_flags & O_DIRECT) && + (req->file->f_mode & FMODE_DIO_PARALLEL_WRITE)) + should_hash = false; + if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL)) io_wq_hash_work(&req->work, file_inode(req->file)); } else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) { if (def->unbound_nonreg_file) |