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From:   Pengfei Li <lpf.vector@gmail.com>
To:     akpm@linux-foundation.org
Cc:     mgorman@techsingularity.net, mhocko@suse.com, vbabka@suse.cz,
        cai@lca.pw, aryabinin@virtuozzo.com, osalvador@suse.de,
        rostedt@goodmis.org, mingo@redhat.com,
        pavel.tatashin@microsoft.com, rppt@linux.ibm.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Pengfei Li <lpf.vector@gmail.com>
Subject: [PATCH 00/10] make "order" unsigned int
Date:   Fri, 26 Jul 2019 02:42:43 +0800
Message-Id: <20190725184253.21160-1-lpf.vector@gmail.com>
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Objective
----
The motivation for this series of patches is use unsigned int for
"order" in compaction.c, just like in other memory subsystems.

In addition, did some cleanup about "order" in page_alloc
and vmscan.


Description
----
Directly modifying the type of "order" to unsigned int is ok in most
places, because "order" is always non-negative.

But there are two places that are special, one is next_search_order()
and the other is compact_node().

For next_search_order(), order may be negative. It can be avoided by
some modifications.

For compact_node(), order = -1 means performing manual compaction.
It can be avoided by specifying order = MAX_ORDER.

Key changes in [PATCH 05/10] mm/compaction: make "order" and
"search_order" unsigned.

More information can be obtained from commit messages.


Test
----
I have done some stress testing locally and have not found any problems.

In addition, local tests indicate no performance impact.


Pengfei Li (10):
  mm/page_alloc: use unsigned int for "order" in should_compact_retry()
  mm/page_alloc: use unsigned int for "order" in __rmqueue_fallback()
  mm/page_alloc: use unsigned int for "order" in should_compact_retry()
  mm/page_alloc: remove never used "order" in alloc_contig_range()
  mm/compaction: make "order" and "search_order" unsigned int in struct
    compact_control
  mm/compaction: make "order" unsigned int in compaction.c
  trace/events/compaction: make "order" unsigned int
  mm/compaction: use unsigned int for "compact_order_failed" in struct
    zone
  mm/compaction: use unsigned int for "kcompactd_max_order" in struct
    pglist_data
  mm/vmscan: use unsigned int for "kswapd_order" in struct pglist_data

 include/linux/compaction.h        |  30 +++----
 include/linux/mmzone.h            |   8 +-
 include/trace/events/compaction.h |  40 +++++-----
 include/trace/events/kmem.h       |   6 +-
 include/trace/events/oom.h        |   6 +-
 include/trace/events/vmscan.h     |   4 +-
 mm/compaction.c                   | 127 +++++++++++++++---------------
 mm/internal.h                     |   6 +-
 mm/page_alloc.c                   |  16 ++--
 mm/vmscan.c                       |   6 +-
 10 files changed, 126 insertions(+), 123 deletions(-)

-- 
2.21.0