Messages in this thread | | | Date | Tue, 22 Jul 2014 14:18:47 +0900 | From | Gioh Kim <> | Subject | [PATCH 0/2] new API to allocate buffer-cache for superblock in non-movable area |
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Hello,
This patch try to solve problem that a long-lasting page cache of ext4 superblock disturbs page migration.
I've been testing CMA feature on my ARM-based platform and found some pages for page caches cannot be migrated. Some of them are page caches of superblock of ext4 filesystem.
Current ext4 reads superblock with sb_bread(). sb_bread() allocates page from movable area. But the problem is that ext4 hold the page until it is unmounted. If root filesystem is ext4 the page cannot be migrated forever.
I introduce a new API for allocating page from non-movable area. It is useful for ext4 and others that want to hold page cache for a long time.
I have 2 patchs:
1. Patch 1/2: introduce a new API that create page cache from non-movable area 2. Patch 2/2: have ext4 use the new API to read superblock
This patchset is based on linux-next-20140717.
Thanks a lot.
Gioh Kim (2): fs/buffer.c: allocate buffer cache from non-movable area ext4: allocate buffer-cache for superblock in non-movable area
fs/buffer.c | 39 ++++++++++++++++++++++++++++++++------- fs/ext4/super.c | 6 +++--- include/linux/buffer_head.h | 8 ++++++++ 3 files changed, 43 insertions(+), 10 deletions(-)
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