linux-kernel - Re: [PATCH v9 06/11] mm/hugetlb: Set the PageHWPoison to the raw error page

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Date:   Wed, 16 Dec 2020 14:28:48 +0100
From:   Oscar Salvador <osalvador@...e.de>
To:     Muchun Song <songmuchun@...edance.com>
Cc:     corbet@....net, mike.kravetz@...cle.com, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
        dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
        viro@...iv.linux.org.uk, akpm@...ux-foundation.org,
        paulmck@...nel.org, mchehab+huawei@...nel.org,
        pawan.kumar.gupta@...ux.intel.com, rdunlap@...radead.org,
        oneukum@...e.com, anshuman.khandual@....com, jroedel@...e.de,
        almasrymina@...gle.com, rientjes@...gle.com, willy@...radead.org,
        mhocko@...e.com, song.bao.hua@...ilicon.com, david@...hat.com,
        duanxiongchun@...edance.com, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v9 06/11] mm/hugetlb: Set the PageHWPoison to the raw
 error page

On Sun, Dec 13, 2020 at 11:45:29PM +0800, Muchun Song wrote:
> Because we reuse the first tail vmemmap page frame and remap it
> with read-only, we cannot set the PageHWPosion on a tail page.
> So we can use the head[4].private to record the real error page
> index and set the raw error page PageHWPoison later.

Maybe the following is better?

"Since the first page of tail page structs is remapped read-only,
 we cannot modify any tail struct page, and so we cannot set
 the HWPoison flag on a tail page.
 We can make use of head[4].private to record the real hwpoisoned
 page index.
 Right before freeing the page the real raw page will be retrieved
 and marked as HWPoison.
"

I think it is slighly clearer, but whatever.

> Signed-off-by: Muchun Song <songmuchun@...edance.com>

I do not quite like the name hwpoison_subpage_deliver, but I cannot
come up with a better one myself, so:

Reviewed-by: Oscar Salvador <osalvador@...e.de>

-- 
Oscar Salvador
SUSE L3