On Mon, 11 May 2020 19:10:08 +0530 Charan Teja Reddy <charante@xxxxxxxxxxxxxx> wrote: > Updating the zone watermarks by any means, like extra_free_kbytes, > min_free_kbytes, water_mark_scale_factor e.t.c, when watermark_boost is > set will result into the higher low and high watermarks than the user > asks. This can be avoided by resetting the zone->watermark_boost to zero > early. Does this solve some problem which has been observed in testing? > ... > > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -7746,9 +7746,9 @@ static void __setup_per_zone_wmarks(void) > mult_frac(zone_managed_pages(zone), > watermark_scale_factor, 10000)); > > + zone->watermark_boost = 0; > zone->_watermark[WMARK_LOW] = min_wmark_pages(zone) + tmp; > zone->_watermark[WMARK_HIGH] = min_wmark_pages(zone) + tmp * 2; > - zone->watermark_boost = 0; > > spin_unlock_irqrestore(&zone->lock, flags); > } This could only be a problem if code is accessing these things without holding zone->lock. Is that ever the case?
