linux-kernel - Re: [PATCH] mm: remove offset check on page->compound

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Date:   Fri, 7 Jan 2022 22:11:20 +0000
From:   Matthew Wilcox <willy@...radead.org>
To:     Wei Yang <richard.weiyang@...il.com>
Cc:     peterz@...radead.org, akpm@...ux-foundation.org, vbabka@...e.cz,
        will@...nel.org, linyunsheng@...wei.com, aarcange@...hat.com,
        feng.tang@...el.com, ebiederm@...ssion.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: remove offset check on page->compound_head and
 folio->lru

On Fri, Jan 07, 2022 at 01:40:59PM +0000, Wei Yang wrote:
> On Fri, Jan 07, 2022 at 03:59:01AM +0000, Matthew Wilcox wrote:
> >On Thu, Jan 06, 2022 at 11:52:54PM +0000, Wei Yang wrote:
> >> FOLIO_MATCH() is used to make sure struct page and folio has identical
> >> layout for the first several words.
> >> 
> >> The comparison of offset between page->compound_head and folio->lru is
> >> more like an internal check in struct page.
> >> 
> >> This patch just removes it.
> >> 
> >> Signed-off-by: Wei Yang <richard.weiyang@...il.com>
> >
> >No.
> 
> Hi, Matthew
> 
> Would you mind sharing some insight on this check?

It's right there in the comments.  If you can't be bothered to read,
why should I write?