Messages in this thread | | | Date | Wed, 5 Jan 2022 16:17:06 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] mm/vmscan.c: no need to double-check if free pages are under high-watermark |
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On Sun, 2 Jan 2022 12:31:29 +0900 skseofh@gmail.com wrote:
> From: Daero Lee <skseofh@gmail.com> > > In kswapd_try_to_sleep function, to check whether kswapd can sleep, > the prepare_kswapd_sleep function is called twice. > > If free pages are below high-watermark in the first call, > the @remaining variable is not updated at 0 and the > prepare_kswapd_sleep function is called for the second time. > > I think it is necessary to set the initial value of the > @remaining to a non-zero value to prevent consecutive calls > to the same function.
Seems right. Mel & Joonsoo, could you please check?
> --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -4331,7 +4331,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx) > /* > * Return the order kswapd stopped reclaiming at as > * prepare_kswapd_sleep() takes it into account. If another caller > - * entered the allocator slow path while kswapd was awake, order will > + * entered the allqocator slow path while kswapd was awake, order will
whoops.
> * remain at the higher level. > */ > return sc.order; > @@ -4355,7 +4355,7 @@ static enum zone_type kswapd_highest_zoneidx(pg_data_t *pgdat, > static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order, > unsigned int highest_zoneidx) > { > - long remaining = 0; > + long remaining = ~0; > DEFINE_WAIT(wait); > > if (freezing(current) || kthread_should_stop())
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