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

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Message-ID: <5B45E17D.2090205@intel.com>
Date:   Wed, 11 Jul 2018 18:52:45 +0800
From:   Wei Wang <wei.w.wang@...el.com>
To:     Michal Hocko <mhocko@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.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 07/11/2018 05:21 PM, Michal Hocko wrote:
> On Tue 10-07-18 18:44:34, Linus Torvalds wrote:
> [...]
>> That was what I tried to encourage with actually removing the pages
>> form the page list. That would be an _incremental_ interface. You can
>> remove MAX_ORDER-1 pages one by one (or a hundred at a time), and mark
>> them free for ballooning that way. And if you still feel you have tons
>> of free memory, just continue removing more pages from the free list.
> We already have an interface for that. alloc_pages(GFP_NOWAIT, MAX_ORDER -1).
> So why do we need any array based interface?

Yes, I'm trying to get free pages directly via alloc_pages, so there 
will be no new mm APIs.
I plan to let free page allocation stop when the remaining system free 
memory becomes close to min_free_kbytes (prevent swapping).


Best,
Wei