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| author |   Arun KS <arunks@codeaurora.org> | 2018-12-28 00:34:20 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:47 -0800 |
| commit | 3d6357de8aa09e1966770dc1171c72679946464f (patch) | |
| tree | a24bb2f8795ea4927c1ff64d5f5f00398bee925d /net/dccp | |
| parent | mm: remove reset of pcp->counter in pageset_init() (diff) | |
| download | linux-dev-3d6357de8aa09e1966770dc1171c72679946464f.tar.xz linux-dev-3d6357de8aa09e1966770dc1171c72679946464f.zip | |
mm: reference totalram_pages and managed_pages once per function
Patch series "mm: convert totalram_pages, totalhigh_pages and managed
pages to atomic", v5.
This series converts totalram_pages, totalhigh_pages and
zone->managed_pages to atomic variables.
totalram_pages, zone->managed_pages and totalhigh_pages updates are
protected by managed_page_count_lock, but readers never care about it.
Convert these variables to atomic to avoid readers potentially seeing a
store tear.
Main motivation was that managed_page_count_lock handling was complicating
things. It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 It seemes better
to remove the lock and convert variables to atomic. With the change,
preventing poteintial store-to-read tearing comes as a bonus.
This patch (of 4):
This is in preparation to a later patch which converts totalram_pages and
zone->managed_pages to atomic variables. Please note that re-reading the
value might lead to a different value and as such it could lead to
unexpected behavior. There are no known bugs as a result of the current
code but it is better to prevent from them in principle.
Link: http://lkml.kernel.org/r/1542090790-21750-2-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/dccp')
| -rw-r--r-- | net/dccp/proto.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 2cc5fbb1b29e..ff727ff61b5b 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -1131,6 +1131,7 @@ EXPORT_SYMBOL_GPL(dccp_debug); static int __init dccp_init(void) { unsigned long goal; + unsigned long nr_pages = totalram_pages; int ehash_order, bhash_order, i; int rc; @@ -1157,10 +1158,10 @@ static int __init dccp_init(void) * * The methodology is similar to that of the buffer cache. */ - if (totalram_pages >= (128 * 1024)) - goal = totalram_pages >> (21 - PAGE_SHIFT); + if (nr_pages >= (128 * 1024)) + goal = nr_pages >> (21 - PAGE_SHIFT); else - goal = totalram_pages >> (23 - PAGE_SHIFT); + goal = nr_pages >> (23 - PAGE_SHIFT); if (thash_entries) goal = (thash_entries * |