From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Markus Trippelsdorf <markus@trippelsdorf.de>,
Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Rik van Riel <riel@redhat.com>
Subject: Re: Current mainline git (24e700e291d52bd2) hangs when building e.g. perf
Date: Sun, 17 Sep 2017 19:04:11 +0200 [thread overview]
Message-ID: <20170917170411.6lvwixxtmx3mbyrd@gmail.com> (raw)
In-Reply-To: <CALCETrW25qXHbs215amZi+fwfyY5yW+2ZpDUVYQHirYSUHJVtg@mail.gmail.com>
* Andy Lutomirski <luto@kernel.org> wrote:
> PeterZ and Ingo, would you be okay with adding a define so arches can
> opt out of the task_struct::active_mm field entirely? That is, with
> the option set, task_struct wouldn't have an active_mm field, the core
> wouldn't call mmgrab and mmdrop, and the arch would be responsible for
> that bookkeeping instead? x86, and presumably all arches without
> cross-core invalidation, would probably prefer to just shoot down the
> old mm entirely in __mmput() rather than trying to figure out when do
> finish freeing old mms. After all, exit_mmap() is going to send an
> IPI regardless, so I see no reason to have the scheduler core pin an
> old dead mm just because some random kernel thread's active_mm field
> points to it.
>
> IOW, if I'm going to reintroduce something like what the old lazy mode
> did on x86, I'd rather do it right.
How realistic would it be to get rid of ::active_mm on all architectures
at once?
Thanks,
Ingo
next prev parent reply other threads:[~2017-09-17 17:04 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-05 7:27 Current mainline git (24e700e291d52bd2) hangs when building e.g. perf Markus Trippelsdorf
2017-09-05 8:53 ` Peter Zijlstra
2017-09-05 9:55 ` Markus Trippelsdorf
2017-09-06 12:52 ` Thomas Gleixner
2017-09-06 13:15 ` Markus Trippelsdorf
2017-09-07 6:28 ` Markus Trippelsdorf
2017-09-08 5:35 ` Markus Trippelsdorf
2017-09-08 6:26 ` Thomas Gleixner
2017-09-08 8:05 ` Borislav Petkov
2017-09-08 9:16 ` Borislav Petkov
2017-09-08 9:48 ` Markus Trippelsdorf
2017-09-08 10:35 ` Ingo Molnar
2017-09-08 10:39 ` Markus Trippelsdorf
2017-09-08 11:30 ` Markus Trippelsdorf
2017-09-08 16:12 ` Andy Lutomirski
2017-09-08 17:16 ` Markus Trippelsdorf
2017-09-08 21:47 ` Andy Lutomirski
2017-09-08 21:56 ` Borislav Petkov
2017-09-08 23:07 ` Andy Lutomirski
2017-09-08 23:23 ` Linus Torvalds
2017-09-09 0:00 ` Andy Lutomirski
2017-09-09 1:05 ` Linus Torvalds
2017-09-09 1:39 ` Andy Lutomirski
2017-09-09 17:49 ` Andy Lutomirski
2017-09-09 18:02 ` Linus Torvalds
2017-09-09 6:39 ` Markus Trippelsdorf
2017-09-09 10:18 ` Borislav Petkov
2017-09-09 11:07 ` Markus Trippelsdorf
2017-09-09 13:07 ` Borislav Petkov
2017-09-09 13:37 ` Markus Trippelsdorf
2017-09-09 13:39 ` Markus Trippelsdorf
2017-09-09 14:07 ` Borislav Petkov
2017-09-09 14:20 ` Markus Trippelsdorf
2017-09-09 14:33 ` Borislav Petkov
2017-09-09 14:43 ` Markus Trippelsdorf
2017-09-09 16:32 ` Markus Trippelsdorf
2017-09-09 17:05 ` Borislav Petkov
2017-09-09 17:23 ` Markus Trippelsdorf
2017-09-09 17:36 ` Borislav Petkov
2017-09-09 18:14 ` Markus Trippelsdorf
2017-09-09 18:26 ` Borislav Petkov
2017-09-09 18:46 ` Markus Trippelsdorf
2017-09-09 19:11 ` Borislav Petkov
2017-09-09 19:19 ` Borislav Petkov
2017-09-09 18:26 ` Linus Torvalds
2017-09-09 18:29 ` Borislav Petkov
2017-09-09 18:47 ` Linus Torvalds
2017-09-09 19:09 ` Borislav Petkov
2017-09-09 19:21 ` Linus Torvalds
2017-09-09 19:28 ` Andy Lutomirski
2017-09-09 19:37 ` Borislav Petkov
2017-09-10 4:42 ` Andy Lutomirski
2017-09-10 20:22 ` Peter Zijlstra
2017-09-10 20:25 ` Andy Lutomirski
2017-09-17 17:04 ` Ingo Molnar [this message]
2017-09-11 1:12 ` Rik van Riel
2017-09-11 1:46 ` Andy Lutomirski
2017-09-11 15:08 ` Rik van Riel
2017-09-12 7:14 ` Markus Trippelsdorf
2017-09-09 8:13 ` Markus Trippelsdorf
2017-09-08 14:51 ` Borislav Petkov
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