From: Kanchan Joshi <[email protected]>
To: Jens Axboe <[email protected]>
Cc: Matthew Wilcox <[email protected]>,
[email protected], [email protected], [email protected],
[email protected], [email protected],
[email protected], [email protected],
[email protected], [email protected],
[email protected], [email protected],
Selvakumar S <[email protected]>,
Nitesh Shetty <[email protected]>,
Javier Gonzalez <[email protected]>
Subject: Re: [PATCH v3 4/4] io_uring: add support for zone-append
Date: Wed, 8 Jul 2020 18:28:05 +0530 [thread overview]
Message-ID: <20200708125805.GA16495@test-zns> (raw)
In-Reply-To: <[email protected]>
[-- Attachment #1: Type: text/plain, Size: 2319 bytes --]
On Tue, Jul 07, 2020 at 04:37:55PM -0600, Jens Axboe wrote:
>On 7/7/20 4:18 PM, Matthew Wilcox wrote:
>> On Tue, Jul 07, 2020 at 02:40:06PM -0600, Jens Axboe wrote:
>>>>> so we have another 24 bytes before io_kiocb takes up another cacheline.
>>>>> If that's a serious problem, I have an idea about how to shrink struct
>>>>> kiocb by 8 bytes so struct io_rw would have space to store another
>>>>> pointer.
>>>> Yes, io_kiocb has room. Cache-locality wise whether that is fine or
>>>> it must be placed within io_rw - I'll come to know once I get to
>>>> implement this. Please share the idea you have, it can come handy.
>>>
>>> Except it doesn't, I'm not interested in adding per-request type fields
>>> to the generic part of it. Before we know it, we'll blow past the next
>>> cacheline.
>>>
>>> If we can find space in the kiocb, that'd be much better. Note that once
>>> the async buffered bits go in for 5.9, then there's no longer a 4-byte
>>> hole in struct kiocb.
>>
>> Well, poot, I was planning on using that. OK, how about this:
>
>Figured you might have had your sights set on that one, which is why I
>wanted to bring it up upfront :-)
>
>> +#define IOCB_NO_CMPL (15 << 28)
>>
>> struct kiocb {
>> [...]
>> - void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
>> + loff_t __user *ki_uposp;
>> - int ki_flags;
>> + unsigned int ki_flags;
>>
>> +typedef void ki_cmpl(struct kiocb *, long ret, long ret2);
>> +static ki_cmpl * const ki_cmpls[15];
>>
>> +void ki_complete(struct kiocb *iocb, long ret, long ret2)
>> +{
>> + unsigned int id = iocb->ki_flags >> 28;
>> +
>> + if (id < 15)
>> + ki_cmpls[id](iocb, ret, ret2);
>> +}
>>
>> +int kiocb_cmpl_register(void (*cb)(struct kiocb *, long, long))
>> +{
>> + for (i = 0; i < 15; i++) {
>> + if (ki_cmpls[id])
>> + continue;
>> + ki_cmpls[id] = cb;
>> + return id;
>> + }
>> + WARN();
>> + return -1;
>> +}
>
>That could work, we don't really have a lot of different completion
>types in the kernel.
Thanks, this looks sorted.
The last thing is about the flag used to trigger this processing.
Will it be fine to intoduce new flag (RWF_APPEND2 or RWF_APPEND_OFFSET)
instead of using RWF_APPEND?
New flag will do what RWF_APPEND does and will also return the
written-location (and therefore expects pointer setup in application).
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next prev parent reply other threads:[~2020-07-08 13:40 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200705185204epcas5p3adeb4fc3473c5fc0472a7396783c5267@epcas5p3.samsung.com>
2020-07-05 18:47 ` [PATCH v3 0/4] zone-append support in io-uring and aio Kanchan Joshi
[not found] ` <CGME20200705185211epcas5p4059d05d2fcedb91829300a7a7d03fda3@epcas5p4.samsung.com>
2020-07-05 18:47 ` [PATCH v3 1/4] fs: introduce FMODE_ZONE_APPEND and IOCB_ZONE_APPEND Kanchan Joshi
[not found] ` <CGME20200705185217epcas5p1cc12d4b892f057a1fe06d73a00869daa@epcas5p1.samsung.com>
2020-07-05 18:47 ` [PATCH v3 2/4] block: add zone append handling for direct I/O path Kanchan Joshi
[not found] ` <CGME20200705185221epcas5p28b6d060df829b751109265222285da0e@epcas5p2.samsung.com>
2020-07-05 18:47 ` [PATCH v3 3/4] block: enable zone-append for iov_iter of bvec type Kanchan Joshi
[not found] ` <CGME20200705185227epcas5p16fba3cb92561794b960184c89fdf2bb7@epcas5p1.samsung.com>
2020-07-05 18:47 ` [PATCH v3 4/4] io_uring: add support for zone-append Kanchan Joshi
2020-07-05 21:00 ` Jens Axboe
2020-07-05 21:09 ` Matthew Wilcox
2020-07-05 21:12 ` Jens Axboe
2020-07-06 14:10 ` Matthew Wilcox
2020-07-06 14:27 ` Jens Axboe
2020-07-06 14:32 ` Matthew Wilcox
2020-07-06 14:33 ` Jens Axboe
2020-07-07 15:11 ` Kanchan Joshi
2020-07-07 15:52 ` Matthew Wilcox
2020-07-07 16:00 ` Christoph Hellwig
2020-07-07 20:23 ` Kanchan Joshi
2020-07-07 20:40 ` Jens Axboe
2020-07-07 22:18 ` Matthew Wilcox
2020-07-07 22:37 ` Jens Axboe
2020-07-08 12:58 ` Kanchan Joshi [this message]
2020-07-08 14:22 ` Matthew Wilcox
2020-07-08 16:41 ` Kanchan Joshi
2020-07-08 14:54 ` Jens Axboe
2020-07-08 14:58 ` Matthew Wilcox
2020-07-08 14:59 ` Jens Axboe
2020-07-08 15:02 ` Matthew Wilcox
2020-07-08 15:06 ` Jens Axboe
2020-07-08 16:08 ` Javier González
2020-07-08 16:33 ` Matthew Wilcox
2020-07-08 16:38 ` Jens Axboe
2020-07-08 17:13 ` Kanchan Joshi
2020-07-08 16:43 ` Javier González
2020-07-06 13:58 ` Kanchan Joshi
2020-07-09 10:15 ` Christoph Hellwig
2020-07-09 13:58 ` Jens Axboe
2020-07-09 14:00 ` Christoph Hellwig
2020-07-09 14:05 ` Jens Axboe
2020-07-09 18:36 ` Kanchan Joshi
2020-07-09 18:50 ` Pavel Begunkov
2020-07-09 18:53 ` Pavel Begunkov
2020-07-09 18:50 ` Jens Axboe
2020-07-09 19:05 ` Kanchan Joshi
2020-07-10 13:10 ` Christoph Hellwig
2020-07-10 13:48 ` Matthew Wilcox
2020-07-10 13:49 ` Christoph Hellwig
2020-07-10 13:51 ` Matthew Wilcox
2020-07-10 14:11 ` Kanchan Joshi
2020-07-20 16:49 ` Kanchan Joshi
2020-07-20 17:14 ` Matthew Wilcox
2020-07-20 20:17 ` Kanchan Joshi
2020-07-21 0:59 ` Damien Le Moal
2020-07-21 1:15 ` Matthew Wilcox
2020-07-21 1:29 ` Jens Axboe
2020-07-21 2:19 ` Damien Le Moal
2020-07-10 14:09 ` Jens Axboe
2020-07-20 16:46 ` Kanchan Joshi
2020-07-10 13:09 ` Christoph Hellwig
2020-07-10 13:29 ` Kanchan Joshi
2020-07-10 13:43 ` Christoph Hellwig
2020-07-20 17:02 ` Kanchan Joshi
2020-07-10 13:57 ` Kanchan Joshi
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