linux-kernel - Re: [PATCH v35 1/5] mm: support to get hints of free page blocks

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Message-ID: <5B46BB46.2080802@intel.com>
Date:   Thu, 12 Jul 2018 10:21:58 +0800
From:   Wei Wang <wei.w.wang@...el.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Michal Hocko <mhocko@...nel.org>
CC:     virtio-dev@...ts.oasis-open.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        virtualization <virtualization@...ts.linux-foundation.org>,
        KVM list <kvm@...r.kernel.org>, linux-mm <linux-mm@...ck.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        liliang.opensource@...il.com, yang.zhang.wz@...il.com,
        quan.xu0@...il.com, nilal@...hat.com,
        Rik van Riel <riel@...hat.com>, peterx@...hat.com
Subject: Re: [PATCH v35 1/5] mm: support to get hints of free page blocks

On 07/12/2018 12:23 AM, Linus Torvalds wrote:
> On Wed, Jul 11, 2018 at 2:21 AM Michal Hocko <mhocko@...nel.org> wrote:
>> We already have an interface for that. alloc_pages(GFP_NOWAIT, MAX_ORDER -1).
>> So why do we need any array based interface?
> That was actually my original argument in the original thread - that
> the only new interface people might want is one that just tells how
> many of those MAX_ORDER-1 pages there are.
>
> See the thread in v33 with the subject
>
>    "[PATCH v33 1/4] mm: add a function to get free page blocks"
>
> and look for me suggesting just using
>
>      #define GFP_MINFLAGS (__GFP_NORETRY | __GFP_NOWARN |
> __GFP_THISNODE | __GFP_NOMEMALLOC)

Would it be better to remove __GFP_THISNODE? We actually want to get all 
the guest free pages (from all the nodes).

Best,
Wei