linux-kernel - Re: [PATCH] mm/madvise: Dont poison entire HugeTLB page for single page errors

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Message-Id: <dd5e2561-b936-7778-75db-5fe25485bf93@linux.vnet.ibm.com>
Date:   Sun, 14 May 2017 08:04:12 +0530
From:   Anshuman Khandual <khandual@...ux.vnet.ibm.com>
To:     Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
        Anshuman Khandual <khandual@...ux.vnet.ibm.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "aneesh.kumar@...ux.vnet.ibm.com" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: Re: [PATCH] mm/madvise: Dont poison entire HugeTLB page for single
 page errors

On 05/12/2017 01:40 PM, Naoya Horiguchi wrote:
> On Thu, Apr 20, 2017 at 04:36:27PM +0530, Anshuman Khandual wrote:
>> Currently soft_offline_page() migrates the entire HugeTLB page, then
>> dequeues it from the active list by making it a dangling HugeTLB page
>> which ofcourse can not be used further and marks the entire HugeTLB
>> page as poisoned. This might be a costly waste of memory if the error
>> involved affects only small section of the entire page.
>>
>> This changes the behaviour so that only the affected page is marked
>> poisoned and then the HugeTLB page is released back to buddy system.
> Hi Anshuman,
> 
> This is a good catch, and we can solve this issue now because freeing
> hwpoisoned page (previously forbidden) is available now.
> 
> And I'm thinking that the same issue for hard/soft-offline on free
> hugepages can be solved, so I'll submit a patchset which includes
> updated version of your patch.

Sure, thanks Naoya.