user/sven/linux.git/include/linux/pageblock-flags.h, branch v5.4.43

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167

2019-05-30T18:26:39Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 83 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Richard Fontana Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070034.021731668@linutronix.de Signed-off-by: Greg Kroah-Hartman

mm/pageblock: throw compile error if pageblock_bits cannot hold MIGRATE_TYPES

2018-12-28T20:11:51Z

Currently, NR_PAGEBLOCK_BITS and MIGRATE_TYPES are not associated by code. If someone adds extra migrate type, then he may forget to enlarge the NR_PAGEBLOCK_BITS. Hence it requires some way to fix. NR_PAGEBLOCK_BITS depends on MIGRATE_TYPES, while these macro spread on two different .h file with reverse dependency, it is a little hard to refer to MIGRATE_TYPES in pageblock-flag.h. This patch tries to remind such relation in compiling-time. Link: http://lkml.kernel.org/r/1544508709-11358-1-git-send-email-kernelfans@gmail.com Signed-off-by: Pingfan Liu Reviewed-by: Andrew Morton Acked-by: Vlastimil Babka Cc: Michal Hocko Cc: Pavel Tatashin Cc: Oscar Salvador Cc: Mike Rapoport Cc: Joonsoo Kim Cc: Alexander Duyck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, compaction: persistently skip hugetlbfs pageblocks

2017-11-18T00:10:00Z

It is pointless to migrate hugetlb memory as part of memory compaction if the hugetlb size is equal to the pageblock order. No defragmentation is occurring in this condition. It is also pointless to for the freeing scanner to scan a pageblock where a hugetlb page is pinned. Unconditionally skip these pageblocks, and do so peristently so that they are not rescanned until it is observed that these hugepages are no longer pinned. It would also be possible to do this by involving the hugetlb subsystem in marking pageblocks to no longer be skipped when they hugetlb pages are freed. This is a simple solution that doesn't involve any additional subsystems in pageblock skip manipulation. [rientjes@google.com: fix build] Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708201734390.117182@chino.kir.corp.google.com Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1708151639130.106658@chino.kir.corp.google.com Signed-off-by: David Rientjes Tested-by: Michal Hocko Cc: Vlastimil Babka Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: use 'unsigned int' for page order

2015-11-07T01:50:42Z

Let's try to be consistent about data type of page order. [sfr@canb.auug.org.au: fix build (type of pageblock_order)] [hughd@google.com: some configs end up with MAX_ORDER and pageblock_order having different types] Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Acked-by: Vlastimil Babka Reviewed-by: Andrea Arcangeli Cc: "Paul E. McKenney" Cc: Andi Kleen Cc: Aneesh Kumar K.V Cc: Christoph Lameter Cc: David Rientjes Cc: Joonsoo Kim Cc: Sergey Senozhatsky Signed-off-by: Stephen Rothwell Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: page_alloc: reduce number of times page_to_pfn is called

2014-06-04T23:54:09Z

In the free path we calculate page_to_pfn multiple times. Reduce that. Signed-off-by: Mel Gorman Acked-by: Rik van Riel Cc: Johannes Weiner Acked-by: Vlastimil Babka Cc: Jan Kara Cc: Michal Hocko Cc: Hugh Dickins Cc: Dave Hansen Cc: Theodore Ts'o Cc: "Paul E. McKenney" Cc: Oleg Nesterov Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: page_alloc: use word-based accesses for get/set pageblock bitmaps

2014-06-04T23:54:09Z

The test_bit operations in get/set pageblock flags are expensive. This patch reads the bitmap on a word basis and use shifts and masks to isolate the bits of interest. Similarly masks are used to set a local copy of the bitmap and then use cmpxchg to update the bitmap if there have been no other changes made in parallel. In a test running dd onto tmpfs the overhead of the pageblock-related functions went from 1.27% in profiles to 0.5%. In addition to the performance benefits, this patch closes races that are possible between: a) get_ and set_pageblock_migratetype(), where get_pageblock_migratetype() reads part of the bits before and other part of the bits after set_pageblock_migratetype() has updated them. b) set_pageblock_migratetype() and set_pageblock_skip(), where the non-atomic read-modify-update set bit operation in set_pageblock_skip() will cause lost updates to some bits changed in the set_pageblock_migratetype(). Joonsoo Kim first reported the case a) via code inspection. Vlastimil Babka's testing with a debug patch showed that either a) or b) occurs roughly once per mmtests' stress-highalloc benchmark (although not necessarily in the same pageblock). Furthermore during development of unrelated compaction patches, it was observed that frequent calls to {start,undo}_isolate_page_range() the race occurs several thousands of times and has resulted in NULL pointer dereferences in move_freepages() and free_one_page() in places where free_list[migratetype] is manipulated by e.g. list_move(). Further debugging confirmed that migratetype had invalid value of 6, causing out of bounds access to the free_list array. That confirmed that the race exist, although it may be extremely rare, and currently only fatal where page isolation is performed due to memory hot remove. Races on pageblocks being updated by set_pageblock_migratetype(), where both old and new migratetype are lower MIGRATE_RESERVE, currently cannot result in an invalid value being observed, although theoretically they may still lead to unexpected creation or destruction of MIGRATE_RESERVE pageblocks. Furthermore, things could get suddenly worse when memory isolation is used more, or when new migratetypes are added. After this patch, the race has no longer been observed in testing. Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Reported-by: Joonsoo Kim Reported-and-tested-by: Vlastimil Babka Cc: Johannes Weiner Cc: Jan Kara Cc: Michal Hocko Cc: Hugh Dickins Cc: Dave Hansen Cc: Theodore Ts'o Cc: "Paul E. McKenney" Cc: Oleg Nesterov Cc: Rik van Riel Cc: Peter Zijlstra Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/pageblock: remove get/set_pageblock_flags

2013-07-03T23:07:32Z

get_pageblock_flags and set_pageblock_flags are not used any more, this patch removes them. Signed-off-by: Wanpeng Li Reviewed-by: Michal Hocko Cc: KAMEZAWA Hiroyuki Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: compaction: fix bit ranges in {get,clear,set}_pageblock_skip()

2012-10-10T23:50:14Z

{get,clear,set}_pageblock_skip() use incorrect bit ranges (please compare to bit ranges used by {get,set}_pageblock_flags() used for migration types) and can overwrite pageblock migratetype of the next pageblock in the bitmap. Signed-off-by: Bartlomiej Zolnierkiewicz Signed-off-by: Kyungmin Park Acked-by: Mel Gorman Tested-by: Thierry Reding Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: compaction: cache if a pageblock was scanned and no pages were isolated

2012-10-09T07:22:50Z

When compaction was implemented it was known that scanning could potentially be excessive. The ideal was that a counter be maintained for each pageblock but maintaining this information would incur a severe penalty due to a shared writable cache line. It has reached the point where the scanning costs are a serious problem, particularly on long-lived systems where a large process starts and allocates a large number of THPs at the same time. Instead of using a shared counter, this patch adds another bit to the pageblock flags called PG_migrate_skip. If a pageblock is scanned by either migrate or free scanner and 0 pages were isolated, the pageblock is marked to be skipped in the future. When scanning, this bit is checked before any scanning takes place and the block skipped if set. The main difficulty with a patch like this is "when to ignore the cached information?" If it's ignored too often, the scanning rates will still be excessive. If the information is too stale then allocations will fail that might have otherwise succeeded. In this patch o CMA always ignores the information o If the migrate and free scanner meet then the cached information will be discarded if it's at least 5 seconds since the last time the cache was discarded o If there are a large number of allocation failures, discard the cache. The time-based heuristic is very clumsy but there are few choices for a better event. Depending solely on multiple allocation failures still allows excessive scanning when THP allocations are failing in quick succession due to memory pressure. Waiting until memory pressure is relieved would cause compaction to continually fail instead of using reclaim/compaction to try allocate the page. The time-based mechanism is clumsy but a better option is not obvious. Signed-off-by: Mel Gorman Acked-by: Rik van Riel Cc: Richard Davies Cc: Shaohua Li Cc: Avi Kivity Acked-by: Rafael Aquini Cc: Fengguang Wu Cc: Michal Nazarewicz Cc: Bartlomiej Zolnierkiewicz Cc: Kyungmin Park Cc: Mark Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

include/linux/pageblock-flags.h: fix set_pageblock_flags() macro definiton

2010-10-26T23:52:05Z

The presently-unused macro was missing one parameter. Signed-off-by: zeal Acked-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds