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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 02/27] block: add REQ_HIPRI_ASYNC
Date: Mon, 10 Dec 2018 17:15:24 -0700	[thread overview]
Message-ID: <20181211001549.30085-3-axboe@kernel.dk> (raw)
In-Reply-To: <20181211001549.30085-1-axboe@kernel.dk>

For the upcoming async polled IO, we can't sleep allocating requests.
If we do, then we introduce a deadlock where the submitter already
has async polled IO in-flight, but can't wait for them to complete
since polled requests must be active found and reaped.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 include/linux/blk_types.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 46c005d601ac..921d734d6b5d 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -347,6 +347,7 @@ enum req_flag_bits {
 #define REQ_NOWAIT		(1ULL << __REQ_NOWAIT)
 #define REQ_NOUNMAP		(1ULL << __REQ_NOUNMAP)
 #define REQ_HIPRI		(1ULL << __REQ_HIPRI)
+#define REQ_HIPRI_ASYNC		(REQ_HIPRI | REQ_NOWAIT)
 
 #define REQ_DRV			(1ULL << __REQ_DRV)
 #define REQ_SWAP		(1ULL << __REQ_SWAP)
-- 
2.17.1


  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 ` Jens Axboe [this message]
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 ` [PATCH 09/27] aio: only use blk plugs for > 2 depth submissions Jens Axboe
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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