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
