From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>,
linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
linux-block@vger.kernel.org, linux-arch@vger.kernel.org,
jmoyer@redhat.com, avi@scylladb.com
Subject: Re: [PATCH 05/16] Add io_uring IO interface
Date: Wed, 9 Jan 2019 19:30:59 +0100 [thread overview]
Message-ID: <20190109183059.GA21824@lst.de> (raw)
In-Reply-To: <1576557b-a65f-86eb-5fcc-00f332ec2dd5@kernel.dk>
On Wed, Jan 09, 2019 at 08:53:31AM -0700, Jens Axboe wrote:
> >> +static int io_setup_rw(int rw, const struct io_uring_iocb *iocb,
> >> + struct iovec **iovec, struct iov_iter *iter)
> >> +{
> >> + void __user *buf = (void __user *)(uintptr_t)iocb->addr;
> >> + size_t ret;
> >> +
> >> + ret = import_single_range(rw, buf, iocb->len, *iovec, iter);
> >> + *iovec = NULL;
> >> + return ret;
> >> +}
> >
> > Is there any point in supporting non-vectored operations here?
>
> Not sure I follow?
This version only supports non-vectored read and write, that is
the equivalent of pread/pwrite. Many AIO users really need vectored
operations, that is preadv/pwritev semantics indirecting through
a struct iovec array. The non-vectored version can be trivially
emulated using a vector of 1, which is what we do in the kernel
I/O stack everywhere. So I think we should just support the vectored
version here, and not the non-vectored one. See my io_uring branch
for the sketeched implementation.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>,
linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
linux-block@vger.kernel.org, linux-arch@vger.kernel.org,
jmoyer@redhat.com, avi@scylladb.com
Subject: Re: [PATCH 05/16] Add io_uring IO interface
Date: Wed, 9 Jan 2019 19:30:59 +0100 [thread overview]
Message-ID: <20190109183059.GA21824@lst.de> (raw)
In-Reply-To: <1576557b-a65f-86eb-5fcc-00f332ec2dd5@kernel.dk>
On Wed, Jan 09, 2019 at 08:53:31AM -0700, Jens Axboe wrote:
> >> +static int io_setup_rw(int rw, const struct io_uring_iocb *iocb,
> >> + struct iovec **iovec, struct iov_iter *iter)
> >> +{
> >> + void __user *buf = (void __user *)(uintptr_t)iocb->addr;
> >> + size_t ret;
> >> +
> >> + ret = import_single_range(rw, buf, iocb->len, *iovec, iter);
> >> + *iovec = NULL;
> >> + return ret;
> >> +}
> >
> > Is there any point in supporting non-vectored operations here?
>
> Not sure I follow?
This version only supports non-vectored read and write, that is
the equivalent of pread/pwrite. Many AIO users really need vectored
operations, that is preadv/pwritev semantics indirecting through
a struct iovec array. The non-vectored version can be trivially
emulated using a vector of 1, which is what we do in the kernel
I/O stack everywhere. So I think we should just support the vectored
version here, and not the non-vectored one. See my io_uring branch
for the sketeched implementation.
--
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next prev parent reply other threads:[~2019-01-09 18:31 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-08 16:56 [PATCHSET v1] io_uring IO interface Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 01/16] fs: add an iopoll method to struct file_operations Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 02/16] block: wire up block device iopoll method Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 03/16] block: add bio_set_polled() helper Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-10 9:43 ` Ming Lei
2019-01-10 9:43 ` Ming Lei
2019-01-10 16:05 ` Jens Axboe
2019-01-10 16:05 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 04/16] iomap: wire up the iopoll method Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 05/16] Add io_uring IO interface Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 12:10 ` Christoph Hellwig
2019-01-09 15:53 ` Jens Axboe
2019-01-09 15:53 ` Jens Axboe
2019-01-09 18:30 ` Christoph Hellwig [this message]
2019-01-09 18:30 ` Christoph Hellwig
2019-01-09 20:07 ` Jens Axboe
2019-01-09 20:07 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 06/16] io_uring: support for IO polling Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 12:11 ` Christoph Hellwig
2019-01-09 15:53 ` Jens Axboe
2019-01-09 15:53 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 07/16] io_uring: add submission side request cache Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 08/16] fs: add fget_many() and fput_many() Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 09/16] io_uring: use fget/fput_many() for file references Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 10/16] io_uring: split kiocb init from allocation Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 12:12 ` Christoph Hellwig
2019-01-09 12:12 ` Christoph Hellwig
2019-01-09 16:56 ` Jens Axboe
2019-01-09 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 11/16] io_uring: batch io_kiocb allocation Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 12:13 ` Christoph Hellwig
2019-01-09 16:57 ` Jens Axboe
2019-01-09 16:57 ` Jens Axboe
2019-01-09 19:03 ` Christoph Hellwig
2019-01-09 20:08 ` Jens Axboe
2019-01-09 20:08 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 12/16] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 12:16 ` Christoph Hellwig
2019-01-09 17:06 ` Jens Axboe
2019-01-09 17:06 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 14/16] io_uring: support kernel side submission Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 19:06 ` Christoph Hellwig
2019-01-09 20:49 ` Jens Axboe
2019-01-09 20:49 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 15/16] io_uring: add submission polling Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-08 16:56 ` [PATCH 16/16] io_uring: add io_uring_event cache hit information Jens Axboe
2019-01-08 16:56 ` Jens Axboe
2019-01-09 16:00 ` [PATCHSET v1] io_uring IO interface Matthew Wilcox
2019-01-09 16:00 ` Matthew Wilcox
2019-01-09 16:27 ` Chris Mason
2019-01-09 16:27 ` Chris Mason
2019-01-12 21:29 [PATCHSET v3] " Jens Axboe
2019-01-12 21:30 ` [PATCH 05/16] Add " Jens Axboe
2019-01-12 21:30 ` Jens Axboe
2019-01-15 2:55 (unknown), Jens Axboe
2019-01-15 2:55 ` [PATCH 05/16] Add io_uring IO interface Jens Axboe
2019-01-15 2:55 ` Jens Axboe
2019-01-15 16:51 ` Jonathan Corbet
2019-01-15 16:51 ` Jonathan Corbet
2019-01-15 16:55 ` Jens Axboe
2019-01-15 16:55 ` Jens Axboe
2019-01-15 17:26 ` Jens Axboe
2019-01-15 17:26 ` Jens Axboe
2019-01-16 10:41 ` Arnd Bergmann
2019-01-16 10:41 ` Arnd Bergmann
2019-01-16 11:00 ` Arnd Bergmann
2019-01-16 11:00 ` Arnd Bergmann
2019-01-16 15:12 ` Jens Axboe
2019-01-16 15:12 ` Jens Axboe
2019-01-16 15:16 ` Arnd Bergmann
2019-01-16 15:16 ` Arnd Bergmann
2019-01-16 15:25 ` Jens Axboe
2019-01-16 15:25 ` Jens Axboe
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