From: Johannes Berg <johannes@sipsolutions.net>
To: Anton Ivanov <anton.ivanov@cambridgegreys.com>,
linux-um@lists.infradead.org
Cc: richard@nod.at
Subject: Re: [PATCH v5] um: Enable preemption in UML
Date: Fri, 22 Sep 2023 10:41:42 +0200 [thread overview]
Message-ID: <210bd25b2dcd9e4424923f55053086f67e219cc4.camel@sipsolutions.net> (raw)
In-Reply-To: <423e8ee5126e1dffda5f8877d07611a21972eea7.camel@sipsolutions.net>
>
> Yes, but when does the fork actually happen?
>
Looking further at this, now I'm confused as to why it doesn't happen
_all_ the time.
I think this has pretty much always been wrong, just now we actually
notice it?
Basically, when we create a new thread (really just mm I think), we say
the first thing that has to run there is fork_handler(), which
initialises things the first time around. This calls force_flush_all()
But of course it's called from __schedule(), which has
preemption/interrupts disabled. So you can't do mmap_read_lock()?
But I'm confused as to why it doesn't seem happen all the time?
johannes
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next prev parent reply other threads:[~2023-09-22 8:41 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 6:52 [PATCH v5] um: Enable preemption in UML anton.ivanov
2023-09-22 7:27 ` Richard Weinberger
2023-09-22 7:29 ` Anton Ivanov
2023-09-22 7:30 ` Johannes Berg
2023-09-22 7:38 ` Anton Ivanov
2023-09-22 7:40 ` Johannes Berg
2023-09-22 8:01 ` Anton Ivanov
2023-09-22 8:13 ` Johannes Berg
2023-09-22 8:40 ` Anton Ivanov
2023-09-22 8:41 ` Johannes Berg [this message]
2023-09-22 8:43 ` Johannes Berg
2023-09-22 9:04 ` Johannes Berg
2023-09-22 9:12 ` Anton Ivanov
2023-09-22 9:06 ` Anton Ivanov
2023-09-22 9:10 ` Johannes Berg
2023-09-22 9:14 ` Johannes Berg
2023-09-22 9:19 ` Anton Ivanov
2023-09-22 9:51 ` Johannes Berg
2023-09-22 9:55 ` Johannes Berg
2023-09-22 10:55 ` Anton Ivanov
2023-09-22 11:17 ` Johannes Berg
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