From: Jeff Moyer <jmoyer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-aio@kvack.org, hch@lst.de
Subject: Re: [PATCH 27/27] aio: add support for pre-mapped user IO buffers
Date: Fri, 30 Nov 2018 17:04:34 -0500 [thread overview]
Message-ID: <x49k1ku5ij1.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <8dc2ea1d-b6a4-728b-7550-87d32240989c@kernel.dk> (Jens Axboe's message of "Fri, 30 Nov 2018 14:57:58 -0700")
Jens Axboe <axboe@kernel.dk> writes:
>>> A limit of 4M is imposed as the largest buffer we currently support.
>>> There's nothing preventing us from going larger, but we need some cap,
>>> and 4M seemed like it would definitely be big enough.
>>
>> Doesn't this mean that a user can pin a bunch of memory? Something like
>> 4MB * aio_max_nr?
>>
>> $ sysctl fs.aio-max-nr
>> fs.aio-max-nr = 1048576
>>
>> If so, it may be a good idea to account the memory under RLIMIT_MEMLOCK.
>
> Yes, it'll need some kind of limiting, right now the limit would indeed
> be aio-max-nr * 4MB. 4G isn't terrible, but...
Unless my math's wrong, that's 4TiB on my system. ;-)
> RLIMIT_MEMLOCK isn't a bad idea.
>
>> I'm not sure how close you are to proposing this patch set for realz.
>> If it's soon (now?), then CC-ing linux-api and writing man pages would
>> be a good idea. I can help out with the libaio bits if you'd like. I
>> haven't yet had time to take this stuff for a spin, sorry. I'll try to
>> get to that soonish.
>
> I am proposing it for real, not sure how long it'll take to get it
> reviewed and moved forward. Unless I get lucky. 4.22 seems like a more
> viable version than 4.21.
>
> I'll take any help I can get on the API/man page parts. And/or testing!
OK, I'll add libaio support (including unit tests), write the man page,
and I'll definitely do some testing. I'll start on all that probably in
the latter half of next week.
>> The speedups are pretty impressive!
>
> That's why I put them in there, maybe that'd get peoples attention :-)
Indeed. :)
Cheers,
Jeff
next prev parent reply other threads:[~2018-12-01 9:15 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-30 16:56 [PATCHSET v4] Support for polled aio Jens Axboe
2018-11-30 16:56 ` [PATCH 01/27] aio: fix failure to put the file pointer Jens Axboe
2018-11-30 17:07 ` Bart Van Assche
2018-11-30 17:08 ` Jens Axboe
2018-11-30 17:24 ` Bart Van Assche
2018-11-30 16:56 ` [PATCH 02/27] aio: clear IOCB_HIPRI Jens Axboe
2018-11-30 17:13 ` Christoph Hellwig
2018-11-30 17:14 ` Jens Axboe
2018-12-04 14:46 ` Christoph Hellwig
2018-12-04 16:40 ` Jens Axboe
2018-11-30 16:56 ` [PATCH 03/27] fs: add an iopoll method to struct file_operations Jens Axboe
2018-11-30 16:56 ` [PATCH 04/27] block: wire up block device iopoll method Jens Axboe
2018-11-30 16:56 ` [PATCH 05/27] block: ensure that async polled IO is marked REQ_NOWAIT Jens Axboe
2018-11-30 17:12 ` Bart Van Assche
2018-11-30 17:17 ` Jens Axboe
2018-12-04 14:48 ` Christoph Hellwig
2018-12-04 18:13 ` Jens Axboe
2018-11-30 16:56 ` [PATCH 06/27] iomap: wire up the iopoll method Jens Axboe
2018-11-30 16:56 ` [PATCH 07/27] iomap: ensure that async polled IO is marked REQ_NOWAIT Jens Axboe
2018-11-30 16:56 ` [PATCH 08/27] aio: use assigned completion handler Jens Axboe
2018-11-30 16:56 ` [PATCH 09/27] aio: separate out ring reservation from req allocation Jens Axboe
2018-11-30 16:56 ` [PATCH 10/27] aio: don't zero entire aio_kiocb aio_get_req() Jens Axboe
2018-12-04 14:49 ` Christoph Hellwig
2018-12-04 15:27 ` Jens Axboe
2018-11-30 16:56 ` [PATCH 11/27] aio: only use blk plugs for > 2 depth submissions Jens Axboe
2018-12-04 14:50 ` Christoph Hellwig
2018-11-30 16:56 ` [PATCH 12/27] aio: use iocb_put() instead of open coding it Jens Axboe
2018-12-04 14:50 ` Christoph Hellwig
2018-11-30 16:56 ` [PATCH 13/27] aio: split out iocb copy from io_submit_one() Jens Axboe
2018-11-30 16:56 ` [PATCH 14/27] aio: abstract out io_event filler helper Jens Axboe
2018-11-30 16:56 ` [PATCH 15/27] aio: add io_setup2() system call Jens Axboe
2018-11-30 16:56 ` [PATCH 16/27] aio: add support for having user mapped iocbs Jens Axboe
2018-11-30 16:56 ` [PATCH 17/27] aio: support for IO polling Jens Axboe
2018-11-30 16:56 ` [PATCH 18/27] aio: add submission side request cache Jens Axboe
2018-11-30 16:56 ` [PATCH 19/27] fs: add fget_many() and fput_many() Jens Axboe
2018-11-30 16:56 ` [PATCH 20/27] aio: use fget/fput_many() for file references Jens Axboe
2018-11-30 16:56 ` [PATCH 21/27] aio: split iocb init from allocation Jens Axboe
2018-11-30 16:56 ` [PATCH 22/27] aio: batch aio_kiocb allocation Jens Axboe
2018-11-30 16:56 ` [PATCH 23/27] block: add BIO_HOLD_PAGES flag Jens Axboe
2018-11-30 16:56 ` [PATCH 24/27] block: implement bio helper to add iter kvec pages to bio Jens Axboe
2018-11-30 19:21 ` Al Viro
2018-11-30 20:15 ` Jens Axboe
2018-11-30 20:32 ` Jens Axboe
2018-11-30 21:11 ` Al Viro
2018-11-30 21:16 ` Jens Axboe
2018-11-30 21:25 ` Al Viro
2018-11-30 21:34 ` Jens Axboe
2018-11-30 22:06 ` Jens Axboe
2018-12-04 14:55 ` Christoph Hellwig
2018-12-04 15:25 ` Jens Axboe
2018-11-30 16:56 ` [PATCH 25/27] fs: add support for mapping an ITER_KVEC for O_DIRECT Jens Axboe
2018-11-30 16:56 ` [PATCH 26/27] iov_iter: add import_kvec() Jens Axboe
2018-11-30 19:17 ` Al Viro
2018-11-30 20:15 ` Jens Axboe
2018-11-30 16:56 ` [PATCH 27/27] aio: add support for pre-mapped user IO buffers Jens Axboe
2018-11-30 21:44 ` Jeff Moyer
2018-11-30 21:57 ` Jens Axboe
2018-11-30 22:04 ` Jeff Moyer [this message]
2018-11-30 22:11 ` Jens Axboe
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