On Fri 23-03-18 15:57:32, Zhaoyang Huang wrote: > For the type of 'ALLOC_HARDER' page allocation, there is an express > highway for the whole process which lead the allocation reach __rmqueue_xxx > easier than other type. > However, when CMA is enabled, the free_page within zone_watermark_ok() will > be deducted for number the pages in CMA type, which may cause the watermark > check fail, but there are possible enough HighAtomic or Unmovable and > Reclaimable pages in the zone. So add 'alloc_harder' here to > count CMA pages in to clean the obstacles on the way to the final. This is no longer the case in the current mmotm tree. Have a look at Joonsoo's zone movable based CMA patchset http://lkml.kernel.org/r/1512114786-5085-1-git-send-email-iamjoonsoo.kim@xxxxxxx > Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxxxxxx> > --- > mm/page_alloc.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 635d7dd..cc18620 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3045,8 +3045,11 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, > > > #ifdef CONFIG_CMA > - /* If allocation can't use CMA areas don't use free CMA pages */ > - if (!(alloc_flags & ALLOC_CMA)) > + /* > + * If allocation can't use CMA areas and no alloc_harder set for none > + * order0 allocation, don't use free CMA pages. > + */ > + if (!(alloc_flags & ALLOC_CMA) && (!alloc_harder || !order)) > free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES); > #endif > > -- > 1.9.1 > -- Michal Hocko SUSE Labs
