From: Feng Tang <feng.tang@intel.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@techsingularity.net>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm/page_alloc: detect allocation forbidden by cpuset and bail out early
Date: Mon, 13 Sep 2021 20:12:33 +0800 [thread overview]
Message-ID: <20210913121233.GD56674@shbuild999.sh.intel.com> (raw)
In-Reply-To: <YT8576cL4tSqmUKI@dhcp22.suse.cz>
On Mon, Sep 13, 2021 at 01:45:51PM +0200, Michal Hocko wrote:
> On Mon 13-09-21 19:34:23, Feng Tang wrote:
> > On Mon, Sep 13, 2021 at 11:15:54AM +0200, Michal Hocko wrote:
> [...]
> > > > +/* Whether the 'nodes' are all movable nodes */
> > > > +static inline bool movable_only_nodes(nodemask_t *nodes)
> > > > +{
> > > > + struct zonelist *zonelist;
> > > > + struct zoneref *z;
> > > > +
> > > > + zonelist = &(first_online_pgdat())->node_zonelists[ZONELIST_FALLBACK];
> > >
> > > This will work but it just begs a question why you haven't chosen a node
> > > from the given nodemask. So I believe it would be easier to read if you
> > > did
> > > zonelist = NODE_DATA(first_node(nodes))->node_zonelists[ZONELIST_FALLBACK]
> >
> > This was also my first try to get the 'zonelist', but from the
> > update_nodemask(), the nodemask could be NULL.
>
> I guess you meant to say s@NULL@empty@
> While this complicates things a bit it is nothing really hard to work
> around. You simply check for nodes_empty() and return false because such
> a nodemask cannot by definition be movable only.
Yes, a nodes_empty() check can solve it, thanks,
- Feng
> --
> Michal Hocko
> SUSE Labs
next prev parent reply other threads:[~2021-09-13 12:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 7:38 [PATCH v2] mm/page_alloc: detect allocation forbidden by cpuset and bail out early Feng Tang
2021-09-13 9:15 ` Michal Hocko
2021-09-13 11:34 ` Feng Tang
2021-09-13 11:45 ` Michal Hocko
2021-09-13 12:12 ` Feng Tang [this message]
2021-09-13 9:40 ` kernel test robot
2021-09-13 10:05 ` kernel test robot
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