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From:   Mina Almasry <almasrymina@google.com>
Date:   Thu, 1 Dec 2022 14:10:37 -0800
Message-ID: <CAHS8izOn3Kr8vqxHYxEoGVoCXKmysRKNsvXpJ2EumxDU6JfSDQ@mail.gmail.com>
Subject: Re: [RFC PATCH v2] mm: Add nodes= arg to memory.reclaim
To:     Shakeel Butt <shakeelb@google.com>
Cc:     Huang Ying <ying.huang@intel.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Yosry Ahmed <yosryahmed@google.com>,
        Tim Chen <tim.c.chen@linux.intel.com>, weixugc@google.com,
        gthelen@google.com, fvdl@google.com, Tejun Heo <tj@kernel.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Muchun Song <songmuchun@bytedance.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
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On Thu, Dec 1, 2022 at 1:32 PM Shakeel Butt <shakeelb@google.com> wrote:
>
> On Tue, Nov 29, 2022 at 06:03:27PM -0800, Mina Almasry wrote:
> [...]
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 7b8e8e43806b..23fc5b523764 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -6735,7 +6735,8 @@ unsigned long mem_cgroup_shrink_node(struct mem_cgroup *memcg,
> >  unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
> >                                          unsigned long nr_pages,
> >                                          gfp_t gfp_mask,
> > -                                        unsigned int reclaim_options)
> > +                                        unsigned int reclaim_options,
> > +                                        nodemask_t nodemask)
>
> Can you please make this parameter a nodemask_t* and pass NULL instead
> of NODE_MASK_ALL?

Thank you very much for the review. I sure can in the next version. To
be honest I thought about that and made the parameter nodemask_t
because I thought the call sites would be more readable. I.e. this:

    try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
MEMCG_RECLAIM_MAY_SWAP,  NODE_MASK_ALL);

Would be more readable than this:

    try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL,
MEMCG_RECLAIM_MAY_SWAP,  NULL);

But the tradeoff is that the callers need include/linux/nodemask.h.
But yes I can fix in the next version.