All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jens Axboe <axboe@kernel.dk>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Kanchan Joshi <joshiiitr@gmail.com>
Cc: Kanchan Joshi <joshi.k@samsung.com>, "hch@lst.de" <hch@lst.de>,
	"kbusch@kernel.org" <kbusch@kernel.org>,
	"io-uring@vger.kernel.org" <io-uring@vger.kernel.org>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	"anuj20.g@samsung.com" <anuj20.g@samsung.com>,
	"javier.gonz@samsung.com" <javier.gonz@samsung.com>
Subject: Re: [RFC 3/3] nvme: wire up support for async passthrough
Date: Thu, 4 Mar 2021 18:46:59 -0700	[thread overview]
Message-ID: <54a2df06-8dde-1302-1109-d54d38ade488@kernel.dk> (raw)
In-Reply-To: <BYAPR04MB49656F0B96D7D1190B293C1186979@BYAPR04MB4965.namprd04.prod.outlook.com>

On 3/4/21 3:59 PM, Chaitanya Kulkarni wrote:
> On 3/4/21 03:01, Kanchan Joshi wrote:
>> On Thu, Mar 4, 2021 at 3:14 AM Chaitanya Kulkarni
>> <Chaitanya.Kulkarni@wdc.com> wrote:
>>> On 3/2/21 23:22, Kanchan Joshi wrote:
>>>> +     if (!ioucmd)
>>>> +             cptr = &c;
>>>> +     else {
>>>> +             /*for async - allocate cmd dynamically */
>>>> +             cptr = kmalloc(sizeof(struct nvme_command), GFP_KERNEL);
>>>> +             if (!cptr)
>>>> +                     return -ENOMEM;
>>>> +     }
>>>> +
>>>> +     memset(cptr, 0, sizeof(c));
>>> Why not kzalloc and remove memset() ?
>> Yes sure. Ideally I want to get rid of the allocation cost. Perhaps
>> employing kmem_cache/mempool can help. Do you think there is a better
>> way?
>>
> 
> Is this hot path ?

It's command issue, and for a bypass (kind of) solution. It's most
definitely the hot path.

-- 
Jens Axboe


WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@kernel.dk>
To: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Kanchan Joshi <joshiiitr@gmail.com>
Cc: Kanchan Joshi <joshi.k@samsung.com>, "hch@lst.de" <hch@lst.de>,
	"kbusch@kernel.org" <kbusch@kernel.org>,
	"io-uring@vger.kernel.org" <io-uring@vger.kernel.org>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
	"anuj20.g@samsung.com" <anuj20.g@samsung.com>,
	"javier.gonz@samsung.com" <javier.gonz@samsung.com>
Subject: Re: [RFC 3/3] nvme: wire up support for async passthrough
Date: Thu, 4 Mar 2021 18:46:59 -0700	[thread overview]
Message-ID: <54a2df06-8dde-1302-1109-d54d38ade488@kernel.dk> (raw)
In-Reply-To: <BYAPR04MB49656F0B96D7D1190B293C1186979@BYAPR04MB4965.namprd04.prod.outlook.com>

On 3/4/21 3:59 PM, Chaitanya Kulkarni wrote:
> On 3/4/21 03:01, Kanchan Joshi wrote:
>> On Thu, Mar 4, 2021 at 3:14 AM Chaitanya Kulkarni
>> <Chaitanya.Kulkarni@wdc.com> wrote:
>>> On 3/2/21 23:22, Kanchan Joshi wrote:
>>>> +     if (!ioucmd)
>>>> +             cptr = &c;
>>>> +     else {
>>>> +             /*for async - allocate cmd dynamically */
>>>> +             cptr = kmalloc(sizeof(struct nvme_command), GFP_KERNEL);
>>>> +             if (!cptr)
>>>> +                     return -ENOMEM;
>>>> +     }
>>>> +
>>>> +     memset(cptr, 0, sizeof(c));
>>> Why not kzalloc and remove memset() ?
>> Yes sure. Ideally I want to get rid of the allocation cost. Perhaps
>> employing kmem_cache/mempool can help. Do you think there is a better
>> way?
>>
> 
> Is this hot path ?

It's command issue, and for a bypass (kind of) solution. It's most
definitely the hot path.

-- 
Jens Axboe


_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2021-03-05  1:47 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20210302160907epcas5p4d04ab7c4ef4d467302498f06ed656b24@epcas5p4.samsung.com>
2021-03-02 16:07 ` [RFC 0/3] Async nvme passthrough Kanchan Joshi
2021-03-02 16:07   ` Kanchan Joshi
2021-03-02 16:07   ` [RFC 1/3] io_uring: add helper for uring_cmd completion in submitter-task Kanchan Joshi
2021-03-02 16:07     ` Kanchan Joshi
2021-03-02 16:07   ` [RFC 2/3] nvme: passthrough helper with callback Kanchan Joshi
2021-03-02 16:07     ` Kanchan Joshi
2021-03-03  7:52     ` Chaitanya Kulkarni
2021-03-03  7:52       ` Chaitanya Kulkarni
2021-03-04 11:13       ` Kanchan Joshi
2021-03-04 11:13         ` Kanchan Joshi
2021-03-05  4:14         ` Chaitanya Kulkarni
2021-03-05  4:14           ` Chaitanya Kulkarni
2021-03-05 10:40           ` Kanchan Joshi
2021-03-05 10:40             ` Kanchan Joshi
2021-03-02 16:07   ` [RFC 3/3] nvme: wire up support for async passthrough Kanchan Joshi
2021-03-02 16:07     ` Kanchan Joshi
2021-03-03  7:34     ` Chaitanya Kulkarni
2021-03-03  7:34       ` Chaitanya Kulkarni
2021-03-04 11:01       ` Kanchan Joshi
2021-03-04 11:01         ` Kanchan Joshi
2021-03-04 22:59         ` Chaitanya Kulkarni
2021-03-04 22:59           ` Chaitanya Kulkarni
2021-03-05  1:46           ` Jens Axboe [this message]
2021-03-05  1:46             ` Jens Axboe
2021-03-05  2:41         ` Keith Busch
2021-03-05  2:41           ` Keith Busch
2021-03-05 10:44           ` Kanchan Joshi
2021-03-05 10:44             ` Kanchan Joshi
2021-03-05 13:17           ` hch
2021-03-05 13:17             ` hch
2021-03-03  7:35     ` Chaitanya Kulkarni
2021-03-03  7:35       ` Chaitanya Kulkarni
2021-03-04 10:55       ` Kanchan Joshi
2021-03-04 10:55         ` Kanchan Joshi
2021-03-05 13:22         ` hch
2021-03-05 13:22           ` hch
2021-03-03  7:37     ` Chaitanya Kulkarni
2021-03-03  7:37       ` Chaitanya Kulkarni

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=54a2df06-8dde-1302-1109-d54d38ade488@kernel.dk \
    --to=axboe@kernel.dk \
    --cc=Chaitanya.Kulkarni@wdc.com \
    --cc=anuj20.g@samsung.com \
    --cc=hch@lst.de \
    --cc=io-uring@vger.kernel.org \
    --cc=javier.gonz@samsung.com \
    --cc=joshi.k@samsung.com \
    --cc=joshiiitr@gmail.com \
    --cc=kbusch@kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.