From: Rafael Aquini <aquini@redhat.com>
To: Gioh Kim <gioh.kim@lge.com>
Cc: jlayton@poochiereds.net, bfields@fieldses.org,
akpm@linux-foundation.org, vbabka@suse.cz,
iamjoonsoo.kim@lge.com, mst@redhat.com, kirill@shutemov.name,
minchan@kernel.org, mgorman@suse.de,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
virtualization@lists.linux-foundation.org, gunho.lee@lge.com
Subject: Re: [RFC 0/4] enable migration of non-LRU pages
Date: Fri, 5 Jun 2015 09:53:51 -0400 [thread overview]
Message-ID: <20150605135350.GE10661@t510.redhat.com> (raw)
In-Reply-To: <1433230065-3573-1-git-send-email-gioh.kim@lge.com>
On Tue, Jun 02, 2015 at 04:27:40PM +0900, Gioh Kim wrote:
> Hello,
>
> This series try to enable migration of non-LRU pages, such as driver's page.
>
> My ARM-based platform occured severe fragmentation problem after long-term
> (several days) test. Sometimes even order-3 page allocation failed. It has
> memory size 512MB ~ 1024MB. 30% ~ 40% memory is consumed for graphic processing
> and 20~30 memory is reserved for zram.
>
> I found that many pages of GPU driver and zram are non-movable pages. So I
> reported Minchan Kim, the maintainer of zram, and he made the internal
> compaction logic of zram. And I made the internal compaction of GPU driver.
>
> They reduced some fragmentation but they are not enough effective.
> They are activated by its own interface, /sys, so they are not cooperative
> with kernel compaction. If there is too much fragmentation and kernel starts
> to compaction, zram and GPU driver cannot work with the kernel compaction.
>
> The first this patch adds a generic isolate/migrate/putback callbacks for page
> address-space. The zram and GPU, and any other modules can register
> its own migration method. The kernel compaction can call the registered
> migration when it works. Therefore all page in the system can be migrated
> at once.
>
> The 2nd the generic migration callbacks are applied into balloon driver.
> My gpu driver code is not open so I apply generic migration into balloon
> to show how it works. I've tested it with qemu enabled by kvm like followings:
> - turn on Ubuntu 14.04 with 1G memory on qemu.
> - do kernel building
> - after several seconds check more than 512MB is used with free command
> - command "balloon 512" in qemu monitor
> - check hundreds MB of pages are migrated
>
> Next kernel compaction code can call generic migration callbacks instead of
> balloon driver interface.
> Finally calling migration of balloon driver is removed.
>
In a glance, ss Konstantin pointed out this set, while it twists chunks around,
brings back code we got rid of a while ago because it was messy and racy.
I'll take a closer look into your work next week, but for now, I'd say
we should not follow this patch of reintroducing long-dead code.
Cheers!
-- Rafael
>
> Gioh Kim (4):
> mm/compaction: enable driver page migration
> mm/balloon: apply migratable-page into balloon driver
> mm/compaction: apply migratable-page into compaction
> mm: remove direct migration of migratable-page
>
> drivers/virtio/virtio_balloon.c | 2 +
> fs/proc/page.c | 4 +-
> include/linux/balloon_compaction.h | 42 +++++++++++++++------
> include/linux/compaction.h | 13 +++++++
> include/linux/fs.h | 2 +
> include/linux/mm.h | 14 +++----
> include/linux/pagemap.h | 27 ++++++++++++++
> include/uapi/linux/kernel-page-flags.h | 2 +-
> mm/balloon_compaction.c | 67 +++++++++++++++++++++++++++++-----
> mm/compaction.c | 9 +++--
> mm/migrate.c | 25 ++++---------
> 11 files changed, 154 insertions(+), 53 deletions(-)
>
> --
> 1.9.1
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
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next prev parent reply other threads:[~2015-06-05 13:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-02 7:27 [RFC 0/4] enable migration of non-LRU pages Gioh Kim
2015-06-02 7:27 ` [RFC 1/4] mm/compaction: enable driver page migration Gioh Kim
2015-06-02 7:27 ` [RFC 2/4] mm/balloon: apply driver page migratable into balloon driver Gioh Kim
2015-06-03 1:49 ` Konstantin Khlebnikov
2015-06-03 4:54 ` Gioh Kim
2015-06-02 7:27 ` [RFC 3/4] mm/compaction: compaction calls generic migration Gioh Kim
2015-06-02 7:27 ` [RFC 4/4] mm: remove direct calling of migration Gioh Kim
2015-06-05 13:53 ` Rafael Aquini [this message]
2015-06-05 14:35 ` [RFC 0/4] enable migration of non-LRU pages Gioh Kim
2015-06-05 14:43 ` Rafael Aquini
2015-06-10 0:08 ` Minchan Kim
2015-06-10 1:08 ` Gioh Kim
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