[RFC PATCH 0/4] mm: reclaim zbud pages on migration and compaction

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

Hi,

Currently zbud pages are not movable and they cannot be allocated from CMA
region. These patches try to address the problem by:
1. Adding a new form of reclaim of zbud pages.
2. Reclaiming zbud pages during migration and compaction.
3. Allocating zbud pages with __GFP_RECLAIMABLE flag.

This reclaim process is different than zbud_reclaim_page(). It acts more
like swapoff() by trying to unuse pages stored in zbud page and bring
them back to memory. The standard zbud_reclaim_page() on the other hand
tries to write them back.

One of patches introduces a new flag: PageZbud. This flag is used in
isolate_migratepages_range() to grab zbud pages and pass them later
for reclaim. Probably this could be replaced with something
smarter than a flag used only in one case.
Any ideas for a better solution are welcome.

This patch set is based on Linux 3.11-rc4.

TODOs:
1. Replace PageZbud flag with other solution.

Best regards,
Krzysztof Kozlowski


Krzysztof Kozlowski (4):
  zbud: use page ref counter for zbud pages
  mm: split code for unusing swap entries from try_to_unuse
  mm: add zbud flag to page flags
  mm: reclaim zbud pages on migration and compaction

 include/linux/page-flags.h |   12 ++
 include/linux/swapfile.h   |    2 +
 include/linux/zbud.h       |   11 +-
 mm/compaction.c            |   20 ++-
 mm/internal.h              |    1 +
 mm/page_alloc.c            |    9 ++
 mm/swapfile.c              |  354 +++++++++++++++++++++++---------------------
 mm/zbud.c                  |  301 +++++++++++++++++++++++++------------
 mm/zswap.c                 |   57 ++++++-
 9 files changed, 499 insertions(+), 268 deletions(-)

-- 
1.7.9.5

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