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Date:   Mon, 29 Jul 2019 17:44:19 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Rik van Riel <riel@surriel.com>
Cc:     Waiman Long <longman@redhat.com>, Ingo Molnar <mingo@redhat.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Phil Auld <pauld@redhat.com>, Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v2] sched/core: Don't use dying mm as active_mm of
 kthreads
Message-ID: <20190729154419.GJ31398@hirez.programming.kicks-ass.net>
References: <20190727171047.31610-1-longman@redhat.com>
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On Mon, Jul 29, 2019 at 11:28:04AM -0400, Rik van Riel wrote:
> On Mon, 2019-07-29 at 17:03 +0200, Peter Zijlstra wrote:
>=20
> > The 'sad' part is that x86 already switches to init_mm on idle and we
> > only keep the active_mm around for 'stupid'.
>=20
> Wait, where do we do that?

drivers/idle/intel_idle.c:              leave_mm(cpu);
drivers/acpi/processor_idle.c:  acpi_unlazy_tlb(smp_processor_id());

> > Rik and Andy were working on getting that 'fixed' a while ago, not
> > sure
> > where that went.
>=20
> My lazy TLB stuff got merged last year.=20

Yes, but we never got around to getting rid of active_mm for x86, right?