From: "H. Peter Anvin" <hpa@zytor.com>
To: Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>
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>,
Steven Rostedt <rostedt@goodmis.org>,
PJ Waskiewicz <pjwaskiewicz@gmail.com>
Subject: Re: [RFC 2/2] x86_64: expand kernel stack to 16K
Date: Fri, 30 May 2014 11:12:09 -0700 [thread overview]
Message-ID: <5388C9F9.3000105@zytor.com> (raw)
In-Reply-To: <5388BEDF.3000202@intel.com>
On 05/30/2014 10:24 AM, Dave Hansen wrote:
> On 05/30/2014 09:06 AM, Linus Torvalds wrote:
>> 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.
>
> If we want to use 4k mappings, we'd need to move the stack over to using
> vmalloc() (or at least be out of the linear mapping) to avoid breaking
> up the linear map's page tables too much. Doing that, we'd actually not
> _have_ to worry about fragmentation, and we could actually utilize the
> per-cpu-pageset code since we'd could be back to using order-0 pages.
> So it's at least not all a loss. Although, I do remember playing with
> 4k stacks back in the 32-bit days and not getting much of a win with it.
>
> We'd definitely that cache, if for no other reason than the vmalloc/vmap
> code as-is isn't super-scalable.
>
I don't think we want to use 4K mappings for production...
-hpa
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next prev parent reply other threads:[~2014-05-30 18:14 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-28 6:53 [PATCH 1/2] ftrace: print stack usage right before Oops Minchan Kim
2014-05-28 6:53 ` [RFC 2/2] x86_64: expand kernel stack to 16K Minchan Kim
2014-05-28 8:37 ` Dave Chinner
2014-05-28 9:13 ` Dave Chinner
2014-05-28 16:06 ` Johannes Weiner
2014-05-28 21:55 ` Dave Chinner
2014-05-29 6:06 ` Minchan Kim
2014-05-28 9:04 ` Michael S. Tsirkin
2014-05-29 1:09 ` Minchan Kim
2014-05-29 2:44 ` Steven Rostedt
2014-05-29 4:11 ` Minchan Kim
2014-05-29 2:47 ` Rusty Russell
2014-05-28 9:27 ` Borislav Petkov
2014-05-29 13:23 ` One Thousand Gnomes
2014-05-28 14:14 ` Steven Rostedt
2014-05-28 14:23 ` H. Peter Anvin
2014-05-28 22:11 ` Dave Chinner
2014-05-28 22:42 ` H. Peter Anvin
2014-05-28 23:17 ` Dave Chinner
2014-05-28 23:21 ` H. Peter Anvin
2014-05-28 15:43 ` Richard Weinberger
2014-05-28 16:08 ` Steven Rostedt
2014-05-28 16:11 ` Richard Weinberger
2014-05-28 16:13 ` Linus Torvalds
2014-05-28 16:09 ` Linus Torvalds
2014-05-28 22:31 ` Dave Chinner
2014-05-28 22:41 ` Linus Torvalds
2014-05-29 1:30 ` Dave Chinner
2014-05-29 1:58 ` Dave Chinner
2014-05-29 2:51 ` Linus Torvalds
2014-05-29 23:36 ` Minchan Kim
2014-05-30 0:05 ` Linus Torvalds
2014-05-30 0:20 ` Minchan Kim
2014-05-30 0:31 ` Linus Torvalds
2014-05-30 0:50 ` Minchan Kim
2014-05-30 1:24 ` Linus Torvalds
2014-05-30 1:58 ` Dave Chinner
2014-05-30 2:13 ` Linus Torvalds
2014-05-30 6:21 ` Minchan Kim
2014-05-30 1:30 ` Linus Torvalds
2014-05-30 0:15 ` Dave Chinner
2014-05-30 2:12 ` Minchan Kim
2014-05-30 4:37 ` Linus Torvalds
2014-05-31 1:45 ` Linus Torvalds
2014-05-30 6:12 ` Minchan Kim
2014-06-03 13:28 ` Rasmus Villemoes
2014-06-03 19:04 ` Linus Torvalds
2014-05-29 2:42 ` Linus Torvalds
2014-05-29 5:14 ` H. Peter Anvin
2014-05-29 6:01 ` Rusty Russell
2014-05-29 7:26 ` virtio ring cleanups, which save stack on older gcc Rusty Russell
2014-05-29 7:26 ` [PATCH 1/4] Hack: measure stack taken by vring from virtio_blk Rusty Russell
2014-05-29 15:39 ` Linus Torvalds
2014-05-29 7:26 ` [PATCH 2/4] virtio_net: pass well-formed sg to virtqueue_add_inbuf() Rusty Russell
2014-05-29 10:07 ` Michael S. Tsirkin
2014-05-29 7:26 ` [PATCH 3/4] virtio_ring: assume sgs are always well-formed Rusty Russell
2014-05-29 11:18 ` Michael S. Tsirkin
2014-05-29 7:26 ` [PATCH 4/4] virtio_ring: unify direct/indirect code paths Rusty Russell
2014-05-29 7:52 ` Peter Zijlstra
2014-05-29 11:05 ` Rusty Russell
2014-05-29 11:33 ` Michael S. Tsirkin
2014-05-29 11:29 ` Michael S. Tsirkin
2014-05-30 2:37 ` Rusty Russell
2014-05-29 7:41 ` virtio ring cleanups, which save stack on older gcc Minchan Kim
2014-05-29 10:39 ` Dave Chinner
2014-05-29 11:08 ` Rusty Russell
2014-05-29 23:45 ` Minchan Kim
2014-05-30 1:06 ` Minchan Kim
2014-05-30 6:56 ` Rusty Russell
2014-05-29 7:26 ` [RFC 2/2] x86_64: expand kernel stack to 16K Dave Chinner
2014-05-29 15:24 ` Linus Torvalds
2014-05-29 23:40 ` Minchan Kim
2014-05-29 23:53 ` Dave Chinner
2014-05-30 0:06 ` Dave Jones
2014-05-30 0:21 ` Dave Chinner
2014-05-30 0:29 ` Dave Jones
2014-05-30 0:32 ` Minchan Kim
2014-05-30 1:34 ` Dave Chinner
2014-05-30 15:25 ` H. Peter Anvin
2014-05-30 15:41 ` Linus Torvalds
2014-05-30 15:52 ` H. Peter Anvin
2014-05-30 16:06 ` Linus Torvalds
2014-05-30 17:24 ` Dave Hansen
2014-05-30 18:12 ` H. Peter Anvin [this message]
2014-05-30 9:48 ` Richard Weinberger
2014-05-30 15:36 ` Linus Torvalds
2014-05-31 2:06 ` Jens Axboe
2014-06-02 22:59 ` Dave Chinner
2014-06-03 13:02 ` Konstantin Khlebnikov
2014-05-29 3:46 ` Minchan Kim
2014-05-29 4:13 ` Linus Torvalds
2014-05-29 5:10 ` Minchan Kim
2014-05-30 21:23 ` Andi Kleen
2014-05-28 16:18 ` [PATCH 1/2] ftrace: print stack usage right before Oops Steven Rostedt
2014-05-29 3:52 ` Minchan Kim
2014-05-29 3:01 ` Steven Rostedt
2014-05-29 3:49 ` Minchan Kim
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