Messages in this thread | | | Subject | Re: [PATCH 3/3] mm: Enable Buddy allocation isolation for CDM nodes | From | Vlastimil Babka <> | Date | Wed, 8 Feb 2017 18:18:09 +0100 |
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On 02/08/2017 03:01 PM, Anshuman Khandual wrote: > This implements allocation isolation for CDM nodes in buddy allocator by > discarding CDM memory zones all the time except in the cases where the gfp > flag has got __GFP_THISNODE or the nodemask contains CDM nodes in cases > where it is non NULL (explicit allocation request in the kernel or user > process MPOL_BIND policy based requests). > > Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> > --- > mm/page_alloc.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 40908de..7d8c82a 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -64,6 +64,7 @@ > #include <linux/page_owner.h> > #include <linux/kthread.h> > #include <linux/memcontrol.h> > +#include <linux/node.h> > > #include <asm/sections.h> > #include <asm/tlbflush.h> > @@ -2908,6 +2909,24 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, > struct page *page; > unsigned long mark; > > + /* > + * CDM nodes get skipped if the requested gfp flag > + * does not have __GFP_THISNODE set or the nodemask > + * does not have any CDM nodes in case the nodemask > + * is non NULL (explicit allocation requests from > + * kernel or user process MPOL_BIND policy which has > + * CDM nodes). > + */ > + if (is_cdm_node(zone->zone_pgdat->node_id)) { > + if (!(gfp_mask & __GFP_THISNODE)) { > + if (!ac->nodemask) > + continue; > + > + if (!nodemask_has_cdm(*ac->nodemask)) > + continue;
nodemask_has_cdm() looks quite expensive, combined with the loop here that's O(n^2). But I don't understand why you need it. If there is no cdm node in the nodemask, then we never reach this code with a cdm node, because the zonelist iterator already checks the nodemask? Am I missing something?
> + } > + } > + > if (cpusets_enabled() && > (alloc_flags & ALLOC_CPUSET) && > !__cpuset_zone_allowed(zone, gfp_mask)) >
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