From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Lieven <pl@kamp.de>,
qemu-devel@nongnu.org, kwolf@redhat.com,
peter.maydell@linaro.org, mst@redhat.com, mreitz@redhat.com,
kraxel@redhat.com
Subject: Re: [Qemu-devel] [PATCH 03/15] coroutine-ucontext: reduce stack size to 64kB
Date: Tue, 28 Jun 2016 11:57:07 +0100 [thread overview]
Message-ID: <20160628105707.GG2243@work-vm> (raw)
In-Reply-To: <c029bea3-3455-da8a-4a42-415c31467155@redhat.com>
* Paolo Bonzini (pbonzini@redhat.com) wrote:
>
>
> On 28/06/2016 11:01, Peter Lieven wrote:
> > evaluation with the recently introduced maximum stack size monitoring revealed
> > that the actual used stack size was never above 4kB so allocating 1MB stack
> > for each coroutine is a lot of wasted memory. So reduce the stack size to
> > 64kB which should still give enough head room.
>
> If we make the stack this much smaller, there is a non-zero chance of
> smashing it. You must add a guard page if you do this (actually more
> than one because QEMU will happily have stack frames as big as 16 KB).
> The stack counts for RSS but it's not actually allocated memory, so why
> does it matter?
I think I'd be interested in seeing the /proc/.../smaps before and after this
change to see if anything is visible and if we can see the difference
in rss etc.
Dave
>
> Paolo
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2016-06-28 10:57 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 9:01 [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 01/15] coroutine-ucontext: mmap stack memory Peter Lieven
2016-06-28 10:02 ` Peter Maydell
2016-06-28 10:21 ` Peter Lieven
2016-06-28 11:04 ` Paolo Bonzini
2016-06-28 9:01 ` [Qemu-devel] [PATCH 02/15] coroutine-ucontext: add a switch to monitor maximum stack size Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 03/15] coroutine-ucontext: reduce stack size to 64kB Peter Lieven
2016-06-28 10:54 ` Paolo Bonzini
2016-06-28 10:57 ` Dr. David Alan Gilbert [this message]
2016-06-28 11:17 ` Peter Lieven
2016-06-28 11:35 ` Dr. David Alan Gilbert
2016-06-28 12:09 ` Peter Lieven
2016-06-28 14:20 ` Dr. David Alan Gilbert
2016-06-30 6:34 ` Peter Lieven
2016-06-28 11:13 ` Peter Lieven
2016-06-28 11:26 ` Paolo Bonzini
2016-06-28 9:01 ` [Qemu-devel] [PATCH 04/15] coroutine: add a knob to disable the shared release pool Peter Lieven
2016-06-28 10:41 ` Paolo Bonzini
2016-06-28 10:47 ` Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 05/15] util: add a helper to mmap private anonymous memory Peter Lieven
2016-10-16 2:10 ` Michael S. Tsirkin
2016-10-18 13:50 ` Alex Bennée
2016-06-28 9:01 ` [Qemu-devel] [PATCH 06/15] exec: use mmap for subpages Peter Lieven
2016-06-28 10:48 ` Paolo Bonzini
2016-06-28 9:01 ` [Qemu-devel] [PATCH 07/15] qapi: use mmap for QmpInputVisitor Peter Lieven
2016-06-28 9:29 ` Dr. David Alan Gilbert
2016-06-28 9:39 ` Peter Lieven
2016-06-28 10:10 ` Daniel P. Berrange
2016-06-28 10:17 ` Dr. David Alan Gilbert
2016-06-28 10:21 ` Daniel P. Berrange
2016-06-28 14:10 ` Eric Blake
2016-06-28 11:36 ` Paolo Bonzini
2016-06-28 14:14 ` Eric Blake
2016-06-30 14:12 ` Markus Armbruster
2016-07-04 9:02 ` Paolo Bonzini
2016-07-04 11:18 ` Markus Armbruster
2016-07-04 11:36 ` Peter Lieven
2016-07-04 11:42 ` Paolo Bonzini
2016-06-28 9:01 ` [Qemu-devel] [PATCH 08/15] virtio: use mmap for VirtQueue Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 09/15] loader: use mmap for ROMs Peter Lieven
2016-06-28 10:41 ` Paolo Bonzini
2016-06-28 11:26 ` Peter Lieven
2016-07-04 7:30 ` Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 10/15] vmware_svga: use mmap for scratch pad Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 11/15] qom: use mmap for bigger Objects Peter Lieven
2016-06-28 10:08 ` Daniel P. Berrange
2016-06-28 10:10 ` Peter Maydell
2016-06-28 10:19 ` Peter Lieven
2016-06-28 10:42 ` Paolo Bonzini
2016-06-28 10:49 ` Peter Lieven
2016-06-30 14:15 ` Markus Armbruster
2016-06-28 9:01 ` [Qemu-devel] [PATCH 12/15] util: add a function to realloc mmapped memory Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 13/15] exec: use mmap for PhysPageMap->nodes Peter Lieven
2016-06-28 10:43 ` Paolo Bonzini
2016-06-28 10:48 ` Peter Lieven
2016-07-11 9:31 ` Peter Lieven
2016-07-11 9:44 ` Peter Lieven
2016-07-11 10:37 ` Paolo Bonzini
2016-07-12 14:34 ` Peter Lieven
2016-07-13 10:27 ` Paolo Bonzini
2016-07-14 14:47 ` Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 14/15] vnc-tight: make the encoding palette static Peter Lieven
2016-06-28 11:12 ` Paolo Bonzini
2016-06-28 11:18 ` Peter Lieven
2016-06-28 9:01 ` [Qemu-devel] [PATCH 15/15] vnc: use mmap for VncState Peter Lieven
2016-06-28 11:37 ` [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage Paolo Bonzini
2016-06-28 12:14 ` Peter Lieven
2016-06-28 12:29 ` Paolo Bonzini
2016-06-28 12:33 ` Peter Lieven
2016-06-28 12:56 ` Paolo Bonzini
2016-06-28 12:56 ` Dr. David Alan Gilbert
2016-06-28 14:43 ` Peter Lieven
2016-06-28 14:52 ` Peter Lieven
2016-10-12 21:18 ` Michael R. Hines
2016-10-18 10:47 ` Peter Lieven
2016-10-19 17:40 ` Michael R. Hines
2016-10-31 22:00 ` Michael R. Hines
2016-11-01 22:02 ` Michael R. Hines
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