path: root/fs/file_table.c
diff options
authorArun KS <arunks@codeaurora.org>2018-12-28 00:34:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:47 -0800
commit3d6357de8aa09e1966770dc1171c72679946464f (patch)
treea24bb2f8795ea4927c1ff64d5f5f00398bee925d /fs/file_table.c
parentmm: remove reset of pcp->counter in pageset_init() (diff)
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')
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);