Messages in this thread | | | Subject | Re: [PATCH 10/10] mm, page_alloc: Only enforce watermarks for order-0 allocations | From | Vlastimil Babka <> | Date | Wed, 30 Sep 2015 16:17:44 +0200 |
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On 09/30/2015 10:46 AM, Mel Gorman wrote: > On Tue, Sep 29, 2015 at 02:05:07PM -0700, Andrew Morton wrote: > > The wizard of oz because because! > > This should fix it up better than clicking my shoes three times. > > ---8<--- > From: Mel Gorman <mgorman@techsingularity.net> > Subject: [PATCH] mm, page_alloc: only enforce watermarks for order-0 > allocations -fix > > This patch is updating comments for clarity and converts a bool to an > int. The code as-is is ok as the compiler is meant to cast it correctly > but it looks odd to people who know the value would be truncated and > lost for other types. > > This is a fix to the mmotm patch > mm-page_alloc-only-enforce-watermarks-for-order-0-allocations.patch > > Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Ack (with nitpick below)
> --- > mm/page_alloc.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 25731624d734..fedec98aafca 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2332,7 +2332,7 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order, > { > long min = mark; > int o; > - const bool alloc_harder = (alloc_flags & ALLOC_HARDER); > + const int alloc_harder = (alloc_flags & ALLOC_HARDER);
How bout the !!(alloc_flags & ALLOC_HARDER) conversion to bool? Unless it forces to make the compiler some extra work...
> > /* free_pages may go negative - that's OK */ > free_pages -= (1 << order) - 1; > @@ -2356,14 +2356,19 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order, > free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES); > #endif > > + /* > + * Check watermarks for an order-0 allocation request. If these > + * are not met, then a high-order request also cannot go ahead > + * even if a suitable page happened to be free. > + */ > if (free_pages <= min + z->lowmem_reserve[classzone_idx]) > return false; > > - /* order-0 watermarks are ok */ > + /* If this is an order-0 request then the watermark is fine */ > if (!order) > return true; > > - /* Check at least one high-order page is free */ > + /* For a high-order request, check at least one suitable page is free */ > for (o = order; o < MAX_ORDER; o++) { > struct free_area *area = &z->free_area[o]; > int mt; >
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