Commit c3a5c77a authored Dec 28, 2018 by Wei Yang Committed by Linus Torvalds Dec 28, 2018

lib/show_mem.c: drop pgdat_resize_lock in show_mem()

Function show_mem() is used to print system memory status when user
requires or fail to allocate memory.  Generally, this is a best effort
information so any races with memory hotplug (or very theoretically an
early initialization) should be tolerable and the worst that could happen
is to print an imprecise node state.

Drop the resize lock because this is the only place which might hold the
lock from the interrupt context and so all other callers might use a
simple spinlock.  Even though this doesn't solve any real issue it makes
the code easier to follow and tiny more effective.

Link: http://lkml.kernel.org/r/20181129235532.9328-1-richard.weiyang@gmail.com


Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 0ecea993

lib/show_mem.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -18,10 +18,8 @@ void show_mem(unsigned int filter, nodemask_t *nodemask)
		show_free_areas(filter, nodemask);

		for_each_online_pgdat(pgdat) {
		unsigned long flags;
		int zoneid;

		pgdat_resize_lock(pgdat, &flags);
		for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
		struct zone *zone = &pgdat->node_zones[zoneid];
		if (!populated_zone(zone))
		@@ -33,7 +31,6 @@ void show_mem(unsigned int filter, nodemask_t *nodemask)
		if (is_highmem_idx(zoneid))
		highmem += zone->present_pages;
		}
		pgdat_resize_unlock(pgdat, &flags);
		}

		printk("%lu pages RAM\n", total);

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