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Date: Thu, 11 Jun 2015 13:41:27 -0700
Message-ID: <CA+55aFyDp_B9q4ReiMsngzQYTWRukrNBYy7uoGfFQ5nVredT9Q@mail.gmail.com>
Subject: Re: [PATCH 07/12] x86/virt/guest/xen: Remove use of pgd_list from the
 Xen guest code
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-mml@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Denys Vlasenko <dvlasenk@redhat.com>, Brian Gerst <brgerst@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>, Waiman Long <Waiman.Long@hp.com>
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On Thu, Jun 11, 2015 at 1:37 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Don't use "for_each_process_thread(g, p)". You only care about each
> mm, and threads all share the same mm, so just do
>
>     for_each_process(p)
>
> instead of iterating over all threads too.

Hmm. I may be wrong. It strikes me that one of the group leaders might
have exited but the subthreads live on. We'd see p->mm being NULL,
even though the mm was originally in use.

Ugh. So maybe the code really does need to iterate over all threads.

                  Linus
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