From: Linus Torvalds <torvalds@linux-foundation.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>,
Linux kernel regressions list <regressions@lists.linux.dev>,
mst@redhat.com, linux-kernel@vger.kernel.org,
konrad.wilk@oracle.com, Thorsten Leemhuis <linux@leemhuis.info>,
virtualization@lists.linux-foundation.org, hch@infradead.org,
ebiederm@xmission.com, stefanha@redhat.com,
nicolas.dichtel@6wind.com
Subject: Re: [PATCH v11 8/8] vhost: use vhost_tasks for worker threads
Date: Mon, 15 May 2023 08:56:39 -0700 [thread overview]
Message-ID: <CAHk-=whmN7cxAgmhDBqiE=c67Q2pp2+SqCknNcj3K+QNKivaSg@mail.gmail.com> (raw)
In-Reply-To: <33b84605-1d0c-1b0e-7927-7ffa96b3c308@kernel.dk>
On Mon, May 15, 2023 at 8:52 AM Jens Axboe <axboe@kernel.dk> wrote:
>
> Only potential downside is that it does make file references more
> expensive for other syscalls, since you now have a shared file table.
> But probably not something to worry about here?
Would the vhost user worker user processes ever be otherwise single-threaded?
I'd *assume* that a vhost user is already doing its own threads. But
maybe that's a completely bogus assumption. I don't actually use any
of this, so...
Because you are obviously 100% right that if you're otherwise
single-threaded, then a CLONE_FILES kernel helper thread will cause
the extra cost for file descriptor lookup/free due to all the race
prevention.
Linus
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next prev parent reply other threads:[~2023-05-15 16:05 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-02 23:25 [PATCH v11 0/8] Use copy_process in vhost layer Mike Christie
2023-02-02 23:25 ` [PATCH v11 1/8] fork: Make IO worker options flag based Mike Christie
2023-02-03 0:14 ` Linus Torvalds
2023-02-02 23:25 ` [PATCH v11 2/8] fork/vm: Move common PF_IO_WORKER behavior to new flag Mike Christie
2023-02-02 23:25 ` [PATCH v11 3/8] fork: add USER_WORKER flag to not dup/clone files Mike Christie
2023-02-03 0:16 ` Linus Torvalds
2023-02-02 23:25 ` [PATCH v11 4/8] fork: Add USER_WORKER flag to ignore signals Mike Christie
2023-02-03 0:19 ` Linus Torvalds
2023-02-05 16:06 ` Mike Christie
2023-02-02 23:25 ` [PATCH v11 5/8] fork: allow kernel code to call copy_process Mike Christie
2023-02-02 23:25 ` [PATCH v11 6/8] vhost_task: Allow vhost layer to use copy_process Mike Christie
2023-02-03 0:43 ` Linus Torvalds
2023-02-02 23:25 ` [PATCH v11 7/8] vhost: move worker thread fields to new struct Mike Christie
2023-02-02 23:25 ` [PATCH v11 8/8] vhost: use vhost_tasks for worker threads Mike Christie
[not found] ` <aba6cca4-e66c-768f-375c-b38c8ba5e8a8@6wind.com>
2023-05-05 18:22 ` Linus Torvalds
2023-05-05 22:37 ` Mike Christie
2023-05-06 1:53 ` Linus Torvalds
2023-05-13 12:39 ` Thorsten Leemhuis
2023-05-13 15:08 ` Linus Torvalds
[not found] ` <20230515-vollrausch-liebgeworden-2765f3ca3540@brauner>
2023-05-15 15:44 ` Linus Torvalds
2023-05-15 15:52 ` Jens Axboe
2023-05-15 15:54 ` Linus Torvalds
2023-05-15 17:23 ` Linus Torvalds
2023-05-15 15:56 ` Linus Torvalds [this message]
2023-05-15 22:23 ` Mike Christie
2023-05-15 22:54 ` Linus Torvalds
2023-05-16 3:53 ` Mike Christie
2023-05-16 13:18 ` Oleg Nesterov
2023-05-16 13:40 ` Oleg Nesterov
2023-05-16 15:56 ` Eric W. Biederman
2023-05-16 18:37 ` Oleg Nesterov
2023-05-16 20:12 ` Eric W. Biederman
2023-05-17 17:09 ` Oleg Nesterov
2023-05-17 18:22 ` Mike Christie
[not found] ` <20230516-weltmeere-backofen-27f12ae2c9e0@brauner>
2023-05-16 16:24 ` Mike Christie
2023-07-20 13:06 ` Michael S. Tsirkin
2023-07-23 4:03 ` michael.christie
2023-07-23 9:31 ` Michael S. Tsirkin
2023-08-10 18:57 ` Michael S. Tsirkin
2023-08-11 18:51 ` Mike Christie
2023-08-13 19:01 ` Michael S. Tsirkin
2023-08-14 3:13 ` michael.christie
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