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From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-aio@kvack.org, linux-block@vger.kernel.org,
	linux-man@vger.kernel.org, linux-api@vger.kernel.org, hch@lst.de,
	jmoyer@redhat.com, avi@scylladb.com
Subject: Re: [PATCH 10/18] io_uring: batch io_kiocb allocation
Date: Tue, 29 Jan 2019 18:26:24 +0100	[thread overview]
Message-ID: <20190129172624.GB15347@lst.de> (raw)
In-Reply-To: <20190128213538.13486-11-axboe@kernel.dk>

> -static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx)
> +static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
> +				   struct io_submit_state *state)
>  {
> +	gfp_t gfp = GFP_ATOMIC | __GFP_NOWARN;

No actually in this patch, but why do we do GFP_ATOMIC allocations
here?  We aren't in irq context or under a spinlock.

> +	if (!state)
> +		req = kmem_cache_alloc(req_cachep, gfp);

Add a
		if (!req)
			goto out;

plus the missing braces here..

> +	else if (!state->free_reqs) {
> +		size_t sz;
> +		int ret;
> +
> +		sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
> +		ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz,
> +						state->reqs);
> +		if (ret <= 0)
> +			goto out;
> +		state->free_reqs = ret - 1;
> +		state->cur_req = 1;
> +		req = state->reqs[0];
> +	} else {
> +		req = state->reqs[state->cur_req];
> +		state->free_reqs--;
> +		state->cur_req++;
> +	}
> +
>  	if (req) {
>  		req->ctx = ctx;
>  		req->flags = 0;
>  		return req;
>  	}

... and we don't need this conditional, which would otherwise also
be in the fast path.

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  reply	other threads:[~2019-01-29 17:26 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-28 21:35 [PATCHSET v8] io_uring IO interface Jens Axboe
2019-01-28 21:35 ` [PATCH 01/18] fs: add an iopoll method to struct file_operations Jens Axboe
2019-01-28 21:35 ` [PATCH 02/18] block: wire up block device iopoll method Jens Axboe
2019-01-28 21:35 ` [PATCH 03/18] block: add bio_set_polled() helper Jens Axboe
2019-01-28 21:35 ` [PATCH 04/18] iomap: wire up the iopoll method Jens Axboe
2019-01-28 21:35 ` [PATCH 05/18] Add io_uring IO interface Jens Axboe
2019-01-28 21:53   ` Jeff Moyer
2019-01-28 21:56     ` Jens Axboe
2019-01-28 22:32   ` Jann Horn
2019-01-28 23:46     ` Jens Axboe
2019-01-28 23:59       ` Jann Horn
2019-01-29  0:03         ` Jens Axboe
2019-01-29  0:31           ` Jens Axboe
2019-01-29  0:34             ` Jann Horn
2019-01-29  0:55               ` Jens Axboe
2019-01-29  0:58                 ` Jann Horn
2019-01-29  1:01                   ` Jens Axboe
2019-02-01 16:57         ` Matt Mullins
2019-02-01 17:04           ` Jann Horn
2019-02-01 17:23             ` Jann Horn
2019-02-01 18:05               ` Al Viro
2019-01-29  1:07   ` Jann Horn
2019-01-29  2:21     ` Jann Horn
2019-01-29  2:54       ` Jens Axboe
2019-01-29  3:46       ` Jens Axboe
2019-01-29 15:56         ` Jann Horn
2019-01-29 16:06           ` Jens Axboe
2019-01-29  2:21     ` Jens Axboe
2019-01-29  1:29   ` Jann Horn
2019-01-29  1:31     ` Jens Axboe
2019-01-29  1:32       ` Jann Horn
2019-01-29  2:23         ` Jens Axboe
2019-01-29  7:12   ` Bert Wesarg
2019-01-29 12:12   ` Florian Weimer
2019-01-29 13:35     ` Jens Axboe
2019-01-28 21:35 ` [PATCH 06/18] io_uring: add fsync support Jens Axboe
2019-01-28 21:35 ` [PATCH 07/18] io_uring: support for IO polling Jens Axboe
2019-01-29 17:24   ` Christoph Hellwig
2019-01-29 18:31     ` Jens Axboe
2019-01-29 19:10       ` Jens Axboe
2019-01-29 20:35         ` Jeff Moyer
2019-01-29 20:37           ` Jens Axboe
2019-01-28 21:35 ` [PATCH 08/18] fs: add fget_many() and fput_many() Jens Axboe
2019-01-28 21:35 ` [PATCH 09/18] io_uring: use fget/fput_many() for file references Jens Axboe
2019-01-28 21:56   ` Jann Horn
2019-01-28 22:03     ` Jens Axboe
2019-01-28 21:35 ` [PATCH 10/18] io_uring: batch io_kiocb allocation Jens Axboe
2019-01-29 17:26   ` Christoph Hellwig [this message]
2019-01-29 18:14     ` Jens Axboe
2019-01-28 21:35 ` [PATCH 11/18] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-01-28 21:35 ` [PATCH 12/18] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-28 23:35   ` Jann Horn
2019-01-28 23:50     ` Jens Axboe
2019-01-29  0:36       ` Jann Horn
2019-01-29  1:25         ` Jens Axboe
2019-01-28 21:35 ` [PATCH 13/18] io_uring: add file set registration Jens Axboe
2019-01-28 21:35 ` [PATCH 14/18] io_uring: add submission polling Jens Axboe
2019-01-28 21:35 ` [PATCH 15/18] io_uring: add io_kiocb ref count Jens Axboe
2019-01-29 17:26   ` Christoph Hellwig
2019-01-28 21:35 ` [PATCH 16/18] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-01-28 21:35 ` [PATCH 17/18] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-01-28 21:35 ` [PATCH 18/18] io_uring: add io_uring_event cache hit information Jens Axboe

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