diff options
author | Arun KS <arunks@codeaurora.org> | 2018-12-28 09:34:20 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 21:11:47 +0100 |
commit | 3d6357de8aa09e1966770dc1171c72679946464f (patch) | |
tree | a24bb2f8795ea4927c1ff64d5f5f00398bee925d /fs/file_table.c | |
parent | mm: remove reset of pcp->counter in pageset_init() (diff) | |
download | linux-3d6357de8aa09e1966770dc1171c72679946464f.tar.xz linux-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 'fs/file_table.c')
-rw-r--r-- | fs/file_table.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/file_table.c b/fs/file_table.c index e49af4caf15d..b6e9587f05c7 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -380,10 +380,11 @@ void __init files_init(void) void __init files_maxfiles_init(void) { unsigned long n; - unsigned long memreserve = (totalram_pages - nr_free_pages()) * 3/2; + unsigned long nr_pages = totalram_pages; + unsigned long memreserve = (nr_pages - nr_free_pages()) * 3/2; - memreserve = min(memreserve, totalram_pages - 1); - n = ((totalram_pages - memreserve) * (PAGE_SIZE / 1024)) / 10; + memreserve = min(memreserve, nr_pages - 1); + n = ((nr_pages - memreserve) * (PAGE_SIZE / 1024)) / 10; files_stat.max_files = max_t(unsigned long, n, NR_FILE); } |