From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mike Christie <michael.christie@oracle.com>
Cc: hch@infradead.org, stefanha@redhat.com, jasowang@redhat.com,
mst@redhat.com, sgarzare@redhat.com,
virtualization@lists.linux-foundation.org, brauner@kernel.org,
ebiederm@xmission.com, konrad.wilk@oracle.com,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v11 4/8] fork: Add USER_WORKER flag to ignore signals
Date: Thu, 2 Feb 2023 16:19:57 -0800 [thread overview]
Message-ID: <CAHk-=wjF6j264jDFcY3wgzOUA2RL2SpD2oL5BF9JqCkz3A413Q@mail.gmail.com> (raw)
In-Reply-To: <20230202232517.8695-5-michael.christie@oracle.com>
On Thu, Feb 2, 2023 at 3:25 PM Mike Christie
<michael.christie@oracle.com> wrote:
>
> + if (args->worker_flags & USER_WORKER_SIG_IGN)
> + ignore_signals(p);
Same comment as for the other case.
There are real reasons to avoid bitfields:
- you can't pass addresses to them around
- it's easier to read or assign multiple fields in one go
- they are horrible for ABI issues due to the exact bit ordering and
padding being very subtle
but none of those issues are relevant here, where it's a kernel-internal ABI.
All these use-cases seem to actually be testing one bit at a time, and
the "assignments" are structure initializers for which named bitfields
are actually perfect and just make the initializer more legible.
Linus
WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mike Christie <michael.christie@oracle.com>
Cc: brauner@kernel.org, mst@redhat.com, konrad.wilk@oracle.com,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, hch@infradead.org,
ebiederm@xmission.com, stefanha@redhat.com,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v11 4/8] fork: Add USER_WORKER flag to ignore signals
Date: Thu, 2 Feb 2023 16:19:57 -0800 [thread overview]
Message-ID: <CAHk-=wjF6j264jDFcY3wgzOUA2RL2SpD2oL5BF9JqCkz3A413Q@mail.gmail.com> (raw)
In-Reply-To: <20230202232517.8695-5-michael.christie@oracle.com>
On Thu, Feb 2, 2023 at 3:25 PM Mike Christie
<michael.christie@oracle.com> wrote:
>
> + if (args->worker_flags & USER_WORKER_SIG_IGN)
> + ignore_signals(p);
Same comment as for the other case.
There are real reasons to avoid bitfields:
- you can't pass addresses to them around
- it's easier to read or assign multiple fields in one go
- they are horrible for ABI issues due to the exact bit ordering and
padding being very subtle
but none of those issues are relevant here, where it's a kernel-internal ABI.
All these use-cases seem to actually be testing one bit at a time, and
the "assignments" are structure initializers for which named bitfields
are actually perfect and just make the initializer more legible.
Linus
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next prev parent reply other threads:[~2023-02-03 0:20 UTC|newest]
Thread overview: 176+ 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 ` Mike Christie
2023-02-02 23:25 ` [PATCH v11 1/8] fork: Make IO worker options flag based Mike Christie
2023-02-02 23:25 ` Mike Christie
2023-02-03 0:14 ` Linus Torvalds
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 ` Mike Christie
2023-02-02 23:25 ` [PATCH v11 3/8] fork: add USER_WORKER flag to not dup/clone files Mike Christie
2023-02-02 23:25 ` Mike Christie
2023-02-03 0:16 ` Linus Torvalds
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
2023-02-02 23:25 ` Mike Christie
2023-02-03 0:19 ` Linus Torvalds [this message]
2023-02-03 0:19 ` Linus Torvalds
2023-02-05 16:06 ` Mike Christie
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 ` Mike Christie
2023-02-02 23:25 ` [PATCH v11 6/8] vhost_task: Allow vhost layer to use copy_process Mike Christie
2023-02-02 23:25 ` Mike Christie
2023-02-03 0:43 ` Linus Torvalds
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 ` Mike Christie
2023-02-02 23:25 ` [PATCH v11 8/8] vhost: use vhost_tasks for worker threads Mike Christie
2023-02-02 23:25 ` Mike Christie
2023-05-05 13:40 ` Nicolas Dichtel
2023-05-05 18:22 ` Linus Torvalds
2023-05-05 18:22 ` Linus Torvalds
2023-05-05 22:37 ` Mike Christie
2023-05-05 22:37 ` Mike Christie
2023-05-06 1:53 ` Linus Torvalds
2023-05-06 1:53 ` Linus Torvalds
2023-05-08 17:13 ` Christian Brauner
2023-05-09 8:09 ` Nicolas Dichtel
2023-05-09 8:17 ` Nicolas Dichtel
2023-05-13 12:39 ` Thorsten Leemhuis
2023-05-13 12:39 ` Thorsten Leemhuis
2023-05-13 15:08 ` Linus Torvalds
2023-05-13 15:08 ` Linus Torvalds
2023-05-15 14:23 ` Christian Brauner
2023-05-15 15:44 ` Linus Torvalds
2023-05-15 15:44 ` Linus Torvalds
2023-05-15 15:52 ` Jens Axboe
2023-05-15 15:52 ` Jens Axboe
2023-05-15 15:54 ` Linus Torvalds
2023-05-15 15:54 ` Linus Torvalds
2023-05-15 17:23 ` Linus Torvalds
2023-05-15 17:23 ` Linus Torvalds
2023-05-15 15:56 ` Linus Torvalds
2023-05-15 15:56 ` Linus Torvalds
2023-05-15 22:23 ` Mike Christie
2023-05-15 22:23 ` Mike Christie
2023-05-15 22:54 ` Linus Torvalds
2023-05-15 22:54 ` Linus Torvalds
2023-05-16 3:53 ` Mike Christie
2023-05-16 3:53 ` Mike Christie
2023-05-16 13:18 ` Oleg Nesterov
2023-05-16 13:18 ` Oleg Nesterov
2023-05-16 13:40 ` Oleg Nesterov
2023-05-16 13:40 ` Oleg Nesterov
2023-05-16 15:56 ` Eric W. Biederman
2023-05-16 15:56 ` Eric W. Biederman
2023-05-16 18:37 ` Oleg Nesterov
2023-05-16 18:37 ` Oleg Nesterov
2023-05-16 20:12 ` Eric W. Biederman
2023-05-16 20:12 ` Eric W. Biederman
2023-05-17 17:09 ` Oleg Nesterov
2023-05-17 17:09 ` Oleg Nesterov
2023-05-17 18:22 ` Mike Christie
2023-05-17 18:22 ` Mike Christie
2023-05-16 8:39 ` Christian Brauner
2023-05-16 16:24 ` Mike Christie
2023-05-16 16:24 ` Mike Christie
2023-05-16 16:44 ` Christian Brauner
2023-05-19 12:15 ` [RFC PATCH 0/8] vhost_tasks: Use CLONE_THREAD/SIGHAND Christian Brauner
2023-06-01 7:58 ` Thorsten Leemhuis
2023-06-01 7:58 ` Thorsten Leemhuis
2023-06-01 10:18 ` Nicolas Dichtel
2023-06-01 10:47 ` Christian Brauner
2023-06-01 11:29 ` Thorsten Leemhuis
2023-06-01 11:29 ` Thorsten Leemhuis
2023-06-01 12:26 ` Linus Torvalds
2023-06-01 12:26 ` Linus Torvalds
2023-06-01 16:10 ` Mike Christie
2023-06-01 16:10 ` Mike Christie
2023-05-16 14:06 ` [PATCH v11 8/8] vhost: use vhost_tasks for worker threads Linux regression tracking #adding (Thorsten Leemhuis)
2023-05-26 9:03 ` Linux regression tracking #update (Thorsten Leemhuis)
2023-06-02 11:38 ` Thorsten Leemhuis
2023-07-20 13:06 ` Michael S. Tsirkin
2023-07-20 13:06 ` Michael S. Tsirkin
2023-07-23 4:03 ` michael.christie
2023-07-23 4:03 ` michael.christie
2023-07-23 9:31 ` Michael S. Tsirkin
2023-07-23 9:31 ` Michael S. Tsirkin
2023-08-10 18:57 ` Michael S. Tsirkin
2023-08-10 18:57 ` Michael S. Tsirkin
2023-08-11 18:51 ` Mike Christie
2023-08-11 18:51 ` Mike Christie
2023-08-13 19:01 ` Michael S. Tsirkin
2023-08-13 19:01 ` Michael S. Tsirkin
2023-08-14 3:13 ` michael.christie
2023-08-14 3:13 ` michael.christie
2023-02-07 8:19 ` [PATCH v11 0/8] Use copy_process in vhost layer Christian Brauner
2023-05-18 0:09 [RFC PATCH 0/8] vhost_tasks: Use CLONE_THREAD/SIGHAND Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 0:09 ` [RFC PATCH 1/8] signal: Dequeue SIGKILL even if SIGNAL_GROUP_EXIT/group_exec_task is set Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 2:34 ` Eric W. Biederman
2023-05-18 2:34 ` Eric W. Biederman
2023-05-18 3:49 ` Eric W. Biederman
2023-05-18 3:49 ` Eric W. Biederman
2023-05-18 15:21 ` Mike Christie
2023-05-18 15:21 ` Mike Christie
2023-05-18 16:25 ` Oleg Nesterov
2023-05-18 16:25 ` Oleg Nesterov
2023-05-18 16:42 ` Mike Christie
2023-05-18 16:42 ` Mike Christie
2023-05-18 17:04 ` Oleg Nesterov
2023-05-18 17:04 ` Oleg Nesterov
2023-05-18 18:28 ` Eric W. Biederman
2023-05-18 18:28 ` Eric W. Biederman
2023-05-18 22:57 ` Mike Christie
2023-05-18 22:57 ` Mike Christie
2023-05-19 4:16 ` Eric W. Biederman
2023-05-19 4:16 ` Eric W. Biederman
2023-05-19 23:24 ` Mike Christie
2023-05-19 23:24 ` Mike Christie
2023-05-22 13:30 ` Oleg Nesterov
2023-05-22 13:30 ` Oleg Nesterov
2023-05-18 8:08 ` Christian Brauner
2023-05-18 15:27 ` Mike Christie
2023-05-18 15:27 ` Mike Christie
2023-05-18 17:07 ` Christian Brauner
2023-05-18 18:08 ` Oleg Nesterov
2023-05-18 18:08 ` Oleg Nesterov
2023-05-18 18:12 ` Christian Brauner
2023-05-18 18:23 ` Oleg Nesterov
2023-05-18 18:23 ` Oleg Nesterov
2023-05-18 0:09 ` [RFC PATCH 2/8] vhost/vhost_task: Hook vhost layer into signal handler Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 0:16 ` Linus Torvalds
2023-05-18 0:16 ` Linus Torvalds
2023-05-18 1:01 ` Mike Christie
2023-05-18 1:01 ` Mike Christie
2023-05-18 8:16 ` Christian Brauner
2023-05-18 0:09 ` [RFC PATCH 3/8] fork/vhost_task: Switch to CLONE_THREAD and CLONE_SIGHAND Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 8:18 ` Christian Brauner
2023-05-18 0:09 ` [RFC PATCH 4/8] vhost-net: Move vhost_net_open Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 0:09 ` [RFC PATCH 5/8] vhost: Add callback that stops new work and waits on running ones Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 14:18 ` Christian Brauner
2023-05-18 15:03 ` Mike Christie
2023-05-18 15:03 ` Mike Christie
2023-05-18 15:09 ` Christian Brauner
2023-05-18 18:38 ` Eric W. Biederman
2023-05-18 18:38 ` Eric W. Biederman
2023-05-18 0:09 ` [RFC PATCH 6/8] vhost-scsi: Add callback to stop and wait on works Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 0:09 ` [RFC PATCH 7/8] vhost-net: " Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 0:09 ` [RFC PATCH 8/8] fork/vhost_task: remove no_files Mike Christie
2023-05-18 0:09 ` Mike Christie
2023-05-18 1:04 ` Mike Christie
2023-05-18 1:04 ` Mike Christie
2023-05-18 12:31 ` kernel test robot
2023-05-18 15:30 ` kernel test robot
2023-05-18 23:14 ` kernel test robot
2023-05-19 7:26 ` kernel test robot
2023-05-18 8:25 ` [RFC PATCH 0/8] vhost_tasks: Use CLONE_THREAD/SIGHAND Christian Brauner
2023-05-18 8:40 ` Christian Brauner
2023-05-18 14:30 ` Christian Brauner
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