From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Coly Li <colyli@suse.de>,
axboe@kernel.dk, linux-bcache@vger.kernel.org,
linux-block@vger.kernel.org, hare@suse.de, mkoutny@suse.com
Subject: Re: [PATCH 1/2] bcache: ignore pending signals in bcache_device_init()
Date: Wed, 4 Mar 2020 14:02:09 +0100 [thread overview]
Message-ID: <20200304130208.GE13170@redhat.com> (raw)
In-Reply-To: <20200304124144.GL16139@dhcp22.suse.cz>
On 03/04, Michal Hocko wrote:
>
> /*
> - * Flush all pending signals for this kthread.
> + * Flush all pending signals for this kthread. Please note that this interface
> + * shouldn't be and if there is a need for it then it should be clearly
> + * documented why.
> + *
> + * Existing users should be double checked because most of them are likely
> + * obsolete. Kernel threads are not on the receiving end of signal delivery
> + * unless they explicitly request that by allow_signal() and in that case
> + * flush_signals is almost always a bug
^^^^^^^^^^^^^^^^^^^^^^
I still think this is too strong statement...
Even if it seems that most current users of flush_signals() are wrong.
> because signal should be processed
> + * by kernel_dequeue_signal rather than dropping them on the floor.
Yes, but to remind we need some cleanups to ensure that
s/flush_signals/kernel_dequeue_signal/ is always "safe" even when only a
single signal is allowed,
> The only
> + * exception when flush_signals could be used is a micro-optimization when
> + * only a single signal is allowed when retreiving the specific signal number
> + * is not needed. Please document this usage.
> */
Agreed.
Oleg.
next prev parent reply other threads:[~2020-03-04 13:02 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 9:34 [PATCH 0/2] bcache patches for Linux v5.6-rc5 Coly Li
2020-03-02 9:34 ` [PATCH 1/2] bcache: ignore pending signals in bcache_device_init() Coly Li
2020-03-02 12:27 ` Michal Hocko
2020-03-02 13:29 ` Coly Li
2020-03-02 13:40 ` Michal Hocko
2020-03-02 17:06 ` Coly Li
2020-03-02 17:28 ` Michal Hocko
2020-03-02 17:47 ` Coly Li
2020-03-03 1:22 ` Guoqing Jiang
2020-03-03 1:30 ` Coly Li
2020-03-03 6:58 ` Сорокин Артем Сергеевич
2020-04-13 8:17 ` Coly Li
2020-03-02 13:49 ` Oleg Nesterov
2020-03-02 17:16 ` Coly Li
2020-03-02 17:19 ` Jens Axboe
2020-03-02 17:32 ` Coly Li
2020-03-02 20:33 ` Jens Axboe
2020-03-03 1:08 ` Coly Li
2020-03-03 7:22 ` Hannes Reinecke
2020-03-03 8:05 ` Michal Hocko
2020-03-03 12:19 ` Oleg Nesterov
2020-03-03 16:03 ` Michal Hocko
2020-03-04 11:36 ` Oleg Nesterov
2020-03-04 11:53 ` Oleg Nesterov
2020-03-04 18:42 ` Jens Axboe
2020-03-04 11:57 ` Michal Hocko
2020-03-04 12:13 ` Oleg Nesterov
2020-03-04 12:22 ` Michal Hocko
2020-03-04 12:33 ` Oleg Nesterov
2020-03-04 12:41 ` Michal Hocko
2020-03-04 13:02 ` Oleg Nesterov [this message]
2020-03-04 13:21 ` Michal Hocko
2020-03-02 15:01 ` Jens Axboe
2020-03-02 9:34 ` [PATCH 2/2] bcache: fix code comments for ignore pending signals Coly Li
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