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From: Michal Hocko <mhocko@suse.com>
To: Feng Tang <feng.tang@intel.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	David Rientjes <rientjes@google.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Ben Widawsky <ben.widawsky@intel.com>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	Andrea Arcangeli <aarcange@redhat.com>,
	Mel Gorman <mgorman@techsingularity.net>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Randy Dunlap <rdunlap@infradead.org>,
	Vlastimil Babka <vbabka@suse.cz>, Andi Kleen <ak@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	ying.huang@intel.com
Subject: Re: [PATCH v6 2/6] mm/memplicy: add page allocation function for MPOL_PREFERRED_MANY policy
Date: Wed, 28 Jul 2021 18:14:41 +0200	[thread overview]
Message-ID: <YQGCcQoIMd8r3yGb@dhcp22.suse.cz> (raw)
In-Reply-To: <20210728151810.GD43486@shbuild999.sh.intel.com>

On Wed 28-07-21 23:18:10, Feng Tang wrote:
> On Wed, Jul 28, 2021 at 02:42:26PM +0200, Michal Hocko wrote:
> > On Mon 12-07-21 16:09:30, Feng Tang wrote:
> > > The semantics of MPOL_PREFERRED_MANY is similar to MPOL_PREFERRED,
> > > that it will first try to allocate memory from the preferred node(s),
> > > and fallback to all nodes in system when first try fails.
> > > 
> > > Add a dedicated function for it just like 'interleave' policy.
> > > 
> > > Link: https://lore.kernel.org/r/20200630212517.308045-9-ben.widawsky@intel.com
> > > Suggested-by: Michal Hocko <mhocko@suse.com>
> > > Co-developed-by: Ben Widawsky <ben.widawsky@intel.com>
> > > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> > > Signed-off-by: Feng Tang <feng.tang@intel.com>
> > 
> > It would be better to squash this together with the actual user of the
> > function added by the next patch.
>  
> Ok, will do
> 
> > > ---
> > >  mm/mempolicy.c | 19 +++++++++++++++++++
> > >  1 file changed, 19 insertions(+)
> > > 
> > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> > > index 17b5800b7dcc..d17bf018efcc 100644
> > > --- a/mm/mempolicy.c
> > > +++ b/mm/mempolicy.c
> > > @@ -2153,6 +2153,25 @@ static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
> > >  	return page;
> > >  }
> > >  
> > > +static struct page *alloc_page_preferred_many(gfp_t gfp, unsigned int order,
> > > +						struct mempolicy *pol)
> > 
> > We likely want a node parameter to know which one we want to start with
> > for locality. Callers should use policy_node for that.
>  
> Yes, locality should be considered, something like this?
> 
> 	int pnid, lnid = numa_node_id();
> 
> 	if (is_nodeset(lnid, &pol->nodes))
> 		pnid = local_nid;
> 	else
> 		pnid = first_node(pol->nodes);
> 
> 	page = __alloc_pages(((gfp | __GFP_NOWARN) & ~__GFP_DIRECT_RECLAIM),
> 				order, pnid, &pol->nodes);
> 	if (!page)
> 		page = __alloc_pages(gfp, order, lnid, NULL);
> 	return page;

No. I really meant to get a node argument and use it as it is. Your
callers already have some node preferences. Usually a local node and as
we have a nodemask here then we do not really need to have any special
logic here as mentioned in other email. The preferred node will act only
as a source for the zone list.
-- 
Michal Hocko
SUSE Labs

  parent reply	other threads:[~2021-07-28 16:14 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12  8:09 [PATCH v6 0/6] Introduce multi-preference mempolicy Feng Tang
2021-07-12  8:09 ` [PATCH v6 1/6] mm/mempolicy: Add MPOL_PREFERRED_MANY for multiple preferred nodes Feng Tang
2021-07-28 12:31   ` Michal Hocko
2021-07-28 14:11     ` Feng Tang
2021-07-28 16:12       ` Michal Hocko
2021-07-29  7:09         ` Feng Tang
2021-07-29 13:38           ` Michal Hocko
2021-07-29 15:12             ` Feng Tang
2021-07-29 16:21               ` Michal Hocko
2021-07-30  3:05                 ` Feng Tang
2021-07-30  6:36                   ` Michal Hocko
2021-07-30  7:18                     ` Feng Tang
2021-07-30  7:38                       ` Michal Hocko
2021-08-02  8:11                       ` Feng Tang
2021-08-02 11:14                         ` Michal Hocko
2021-08-02 11:33                           ` Feng Tang
2021-08-02 11:47                             ` Michal Hocko
2021-07-12  8:09 ` [PATCH v6 2/6] mm/memplicy: add page allocation function for MPOL_PREFERRED_MANY policy Feng Tang
2021-07-28 12:42   ` Michal Hocko
2021-07-28 15:18     ` Feng Tang
2021-07-28 15:25       ` Feng Tang
2021-07-28 16:15         ` Michal Hocko
2021-07-28 16:14       ` Michal Hocko [this message]
2021-07-12  8:09 ` [PATCH v6 3/6] mm/mempolicy: enable page allocation for MPOL_PREFERRED_MANY for general cases Feng Tang
2021-07-12  8:09 ` [PATCH v6 4/6] mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY Feng Tang
2021-07-21 20:49   ` Mike Kravetz
2021-07-22  8:11     ` Feng Tang
2021-07-22  9:42     ` Michal Hocko
2021-07-22 16:21       ` Mike Kravetz
2021-07-12  8:09 ` [PATCH v6 5/6] mm/mempolicy: Advertise new MPOL_PREFERRED_MANY Feng Tang
2021-07-28 12:47   ` Michal Hocko
2021-07-28 13:41     ` Feng Tang
2021-07-12  8:09 ` [PATCH v6 6/6] mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies Feng Tang
2021-07-28 12:51   ` Michal Hocko
2021-07-28 13:50     ` Feng Tang
2021-07-15  0:15 ` [PATCH v6 0/6] Introduce multi-preference mempolicy Andrew Morton
2021-07-15  2:13   ` Feng Tang
2021-07-15 18:49   ` Dave Hansen

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