From 476567e8735a0d06225f3873a86dfa0efd95f3a5 Mon Sep 17 00:00:00 2001 From: Arun KS Date: Fri, 28 Dec 2018 00:34:32 -0800 Subject: mm: remove managed_page_count_lock spinlock Now that totalram_pages and managed_pages are atomic varibles, no need of managed_page_count spinlock. The lock had really a weak consistency guarantee. It hasn't been used for anything but the update but no reader actually cares about all the values being updated to be in sync. Link: http://lkml.kernel.org/r/1542090790-21750-5-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS Reviewed-by: Konstantin Khlebnikov Acked-by: Michal Hocko Acked-by: Vlastimil Babka Cc: David Hildenbrand Reviewed-by: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 6 ------ mm/page_alloc.c | 5 ----- 2 files changed, 11 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index a23e34e21178..bc0990c1f1c3 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -428,12 +428,6 @@ struct zone { * Write access to present_pages at runtime should be protected by * mem_hotplug_begin/end(). Any reader who can't tolerant drift of * present_pages should get_online_mems() to get a stable value. - * - * Read access to managed_pages should be safe because it's unsigned - * long. Write access to zone->managed_pages and totalram_pages are - * protected by managed_page_count_lock at runtime. Idealy only - * adjust_managed_page_count() should be used instead of directly - * touching zone->managed_pages and totalram_pages. */ atomic_long_t managed_pages; unsigned long spanned_pages; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index eb2027892ef9..6f3d2c7af84b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -122,9 +122,6 @@ nodemask_t node_states[NR_NODE_STATES] __read_mostly = { }; EXPORT_SYMBOL(node_states); -/* Protect totalram_pages and zone->managed_pages */ -static DEFINE_SPINLOCK(managed_page_count_lock); - atomic_long_t _totalram_pages __read_mostly; EXPORT_SYMBOL(_totalram_pages); unsigned long totalreserve_pages __read_mostly; @@ -7077,14 +7074,12 @@ early_param("movablecore", cmdline_parse_movablecore); void adjust_managed_page_count(struct page *page, long count) { - spin_lock(&managed_page_count_lock); atomic_long_add(count, &page_zone(page)->managed_pages); totalram_pages_add(count); #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) totalhigh_pages_add(count); #endif - spin_unlock(&managed_page_count_lock); } EXPORT_SYMBOL(adjust_managed_page_count); -- cgit v1.2.3-59-g8ed1b