From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-aio@kvack.org
Cc: hch@lst.de, jmoyer@redhat.com, clm@fb.com, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 09/27] aio: only use blk plugs for > 2 depth submissions
Date: Mon, 10 Dec 2018 17:15:31 -0700 [thread overview]
Message-ID: <20181211001549.30085-10-axboe@kernel.dk> (raw)
In-Reply-To: <20181211001549.30085-1-axboe@kernel.dk>
Plugging is meant to optimize submission of a string of IOs, if we don't
have more than 2 being submitted, don't bother setting up a plug.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/aio.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 522c04864d82..ed6c3914477a 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -69,6 +69,12 @@ struct aio_ring {
struct io_event io_events[0];
}; /* 128 bytes + ring size */
+/*
+ * Plugging is meant to work with larger batches of IOs. If we don't
+ * have more than the below, then don't bother setting up a plug.
+ */
+#define AIO_PLUG_THRESHOLD 2
+
#define AIO_RING_PAGES 8
struct kioctx_table {
@@ -1919,7 +1925,8 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
if (nr > ctx->nr_events)
nr = ctx->nr_events;
- blk_start_plug(&plug);
+ if (nr > AIO_PLUG_THRESHOLD)
+ blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
struct iocb __user *user_iocb;
@@ -1932,7 +1939,8 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
if (ret)
break;
}
- blk_finish_plug(&plug);
+ if (nr > AIO_PLUG_THRESHOLD)
+ blk_finish_plug(&plug);
percpu_ref_put(&ctx->users);
return i ? i : ret;
@@ -1959,7 +1967,8 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
if (nr > ctx->nr_events)
nr = ctx->nr_events;
- blk_start_plug(&plug);
+ if (nr > AIO_PLUG_THRESHOLD)
+ blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
compat_uptr_t user_iocb;
@@ -1972,7 +1981,8 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
if (ret)
break;
}
- blk_finish_plug(&plug);
+ if (nr > AIO_PLUG_THRESHOLD)
+ blk_finish_plug(&plug);
percpu_ref_put(&ctx->users);
return i ? i : ret;
--
2.17.1
next prev parent reply other threads:[~2018-12-11 0:16 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-11 0:15 [PATCHSET v7] Support for polled and buffed aio (and more) Jens Axboe
2018-12-11 0:15 ` [PATCH 01/27] fs: add an iopoll method to struct file_operations Jens Axboe
2018-12-11 0:15 ` [PATCH 02/27] block: add REQ_HIPRI_ASYNC Jens Axboe
2018-12-11 0:15 ` [PATCH 03/27] block: wire up block device iopoll method Jens Axboe
2018-12-11 0:15 ` [PATCH 04/27] block: use REQ_HIPRI_ASYNC for non-sync polled IO Jens Axboe
2018-12-11 0:15 ` [PATCH 05/27] iomap: wire up the iopoll method Jens Axboe
2018-12-11 0:15 ` [PATCH 06/27] aio: use assigned completion handler Jens Axboe
2018-12-11 0:15 ` [PATCH 07/27] aio: separate out ring reservation from req allocation Jens Axboe
2018-12-11 0:15 ` [PATCH 08/27] aio: don't zero entire aio_kiocb aio_get_req() Jens Axboe
2018-12-11 0:15 ` Jens Axboe [this message]
2018-12-11 0:15 ` [PATCH 10/27] aio: use iocb_put() instead of open coding it Jens Axboe
2018-12-11 0:15 ` [PATCH 11/27] aio: split out iocb copy from io_submit_one() Jens Axboe
2018-12-11 0:15 ` [PATCH 12/27] aio: abstract out io_event filler helper Jens Axboe
2018-12-11 0:15 ` [PATCH 13/27] aio: add io_setup2() system call Jens Axboe
2018-12-11 0:15 ` [PATCH 14/27] aio: add support for having user mapped iocbs Jens Axboe
2018-12-11 0:15 ` [PATCH 15/27] aio: support for IO polling Jens Axboe
2018-12-11 0:15 ` [PATCH 16/27] aio: add submission side request cache Jens Axboe
2018-12-11 0:15 ` [PATCH 17/27] fs: add fget_many() and fput_many() Jens Axboe
2018-12-11 0:15 ` [PATCH 18/27] aio: use fget/fput_many() for file references Jens Axboe
2018-12-11 0:15 ` [PATCH 19/27] aio: split iocb init from allocation Jens Axboe
2018-12-11 0:15 ` [PATCH 20/27] aio: batch aio_kiocb allocation Jens Axboe
2018-12-11 0:15 ` [PATCH 21/27] block: add BIO_HOLD_PAGES flag Jens Axboe
2018-12-11 0:15 ` [PATCH 22/27] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2018-12-11 0:15 ` [PATCH 23/27] fs: add support for mapping an ITER_BVEC for O_DIRECT Jens Axboe
2018-12-11 0:15 ` [PATCH 24/27] aio: add support for pre-mapped user IO buffers Jens Axboe
2018-12-11 0:15 ` [PATCH 25/27] aio: split old ring complete out from aio_complete() Jens Axboe
2018-12-11 0:15 ` [PATCH 26/27] aio: add support for submission/completion rings Jens Axboe
2018-12-11 0:15 ` [PATCH 27/27] aio: support kernel side submission for aio with SCQRING Jens Axboe
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