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Date: Fri, 30 May 2014 09:06:03 -0700
Message-ID: <CA+55aFwHS2xErW6TgBHGR9JP0QZW9W7GSLec5WzbV+GGYFUu6A@mail.gmail.com>
Subject: Re: [RFC 2/2] x86_64: expand kernel stack to 16K
From: Linus Torvalds <torvalds@linux-foundation.org>
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To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Chinner <david@fromorbit.com>, Minchan Kim <minchan@kernel.org>, Dave Jones <davej@redhat.com>, Jens Axboe <axboe@kernel.dk>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Andrew Morton <akpm@linux-foundation.org>, linux-mm <linux-mm@kvack.org>, Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>, Johannes Weiner <hannes@cmpxchg.org>, Hugh Dickins <hughd@google.com>, Rusty Russell <rusty@rustcorp.com.au>, "Michael S. Tsirkin" <mst@redhat.com>, Dave Hansen <dave.hansen@intel.com>, Steven Rostedt <rostedt@goodmis.org>, PJ Waskiewicz <pjwaskiewicz@gmail.com>

On Fri, May 30, 2014 at 8:52 AM, H. Peter Anvin <hpa@zytor.com> wrote:
>>
>> That said, it's still likely a non-production option due to the page
>> table games we'd have to play at fork/clone time.
>
> Still, seems much more tractable.

We might be able to make it more attractive by having a small
front-end cache of the 16kB allocations with the second page unmapped.
That would at least capture the common "lots of short-lived processes"
case without having to do kernel page table work.

               Linus

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