Re: [RFCv3 0/5] enable migration of driver pages

From: Rafael Aquini
Date: Wed Jul 08 2015 - 21:00:52 EST


On Tue, Jul 07, 2015 at 01:36:20PM +0900, Gioh Kim wrote:
> From: Gioh Kim <gurugio@xxxxxxxxxxx>
>
> 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.
>
> This patch set combines 5 patches.
>
> 1. patch 1/5: get inode from anon_inodes
> This patch adds new interface to create inode from anon_inodes.
>
> 2. patch 2/5: framework to isolate/migrate/putback page
> Add isolatepage, putbackpage into address_space_operations
> and wrapper function to call them
>
> 3. patch 3/5: apply the framework into balloon driver
> The balloon driver is applied into the framework. It gets a inode
> from anon_inodes and register operations in the inode.
> Any other drivers can register operations via inode like this
> to migrate it's pages.
>
> 4. patch 4/5: compaction/migration call the generic interfaces
> Compaction and migration pages call the generic interfaces of the framework,
> instead of calling balloon migration directly.
>
> 5. patch 5/5: remove direct calling of migration of driver pages
> Non-lru pages are migrated with lru pages by move_to_new_page().
>
> This patch set is tested:
> - 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
>
> My thanks to Konstantin Khlebnikov for his reviews of the v2 patch set.
> Most of the changes were based on his feedback.
>
> Changes since v2:
> - change the name of page type from migratable page into mobile page
> - get and lock page to isolate page
> - add wrapper interfaces for page->mapping->a_ops->isolate/putback
> - leave balloon pages marked as balloon
>
> This patch-set is based on v4.1
>
> Gioh Kim (5):
> fs/anon_inodes: new interface to create new inode
> mm/compaction: enable mobile-page migration
> mm/balloon: apply mobile page migratable into balloon
> mm/compaction: call generic migration callbacks
> mm: remove direct calling of migration
>
> drivers/virtio/virtio_balloon.c | 3 ++
> fs/anon_inodes.c | 6 +++
> fs/proc/page.c | 3 ++
> include/linux/anon_inodes.h | 1 +
> include/linux/balloon_compaction.h | 15 +++++--
> include/linux/compaction.h | 76 ++++++++++++++++++++++++++++++++++
> include/linux/fs.h | 2 +
> include/linux/page-flags.h | 19 +++++++++
> include/uapi/linux/kernel-page-flags.h | 1 +
> mm/balloon_compaction.c | 71 ++++++++++---------------------
> mm/compaction.c | 8 ++--
> mm/migrate.c | 24 +++--------
> 12 files changed, 154 insertions(+), 75 deletions(-)
>
> --
> 2.1.4
>
Acked-by: Rafael Aquini <aquini@xxxxxxxxxx>
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