On Fri, 2019-07-26 at 02:42 +0800, Pengfei Li wrote: > Objective > ---- > The motivation for this series of patches is use unsigned int for > "order" in compaction.c, just like in other memory subsystems. I suppose you will need more justification for this change. Right now, I don't see much real benefit apart from possibly introducing more regressions in those tricky areas of the code. Also, your testing seems quite lightweight. > > 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(-) >
