• Nick Piggin's avatar
    [PATCH] sched: less locking · e17224bf
    Nick Piggin authored
    During periodic load balancing, don't hold this runqueue's lock while
    scanning remote runqueues, which can take a non trivial amount of time
    especially on very large systems.
    
    Holding the runqueue lock will only help to stabilise ->nr_running, however
    this doesn't do much to help because tasks being woken will simply get held
    up on the runqueue lock, so ->nr_running would not provide a really
    accurate picture of runqueue load in that case anyway.
    
    What's more, ->nr_running (and possibly the cpu_load averages) of remote
    runqueues won't be stable anyway, so load balancing is always an inexact
    operation.
    Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
    Acked-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    e17224bf
sched.c 137 KB