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From: Matthew Wilcox <willy@infradead.org>
To: Peter Xu <peterx@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Yang Shi <shy828301@gmail.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	David Hildenbrand <david@redhat.com>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	Hugh Dickins <hughd@google.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: Wire up tail page poisoning over ->mappings
Date: Fri, 18 Aug 2023 23:14:28 +0100	[thread overview]
Message-ID: <ZN/tRLy0e+Iod9z3@casper.infradead.org> (raw)
In-Reply-To: <20230815210659.430010-1-peterx@redhat.com>

On Tue, Aug 15, 2023 at 05:06:59PM -0400, Peter Xu wrote:
> I split this out from another rfc series.  Removed RFC tag because it
> wasn't for this patch but for the documentation updates.  I'll post the rfc
> part alone.  Comments welcomed, thanks.

I still hate it, as I explained here:

https://lore.kernel.org/linux-mm/ZNp7yUgUrIpILnXu@casper.infradead.org/

> > + * When the tail page's mapping field reused, it'll be exempted from
> > + * ->mapping poisoning and checks.  Also see the macro TAIL_MAPPING.
> > + */
> > +#define  TAIL_MAPPING_REUSED_MAX  (2)
> 
> More importantly, I think this is over-parametrisation.  If you start to
> use extra fields in struct folio, just change the code in page_alloc.c
> directly.



  reply	other threads:[~2023-08-18 22:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-15 21:06 Peter Xu
2023-08-18 22:14 ` Matthew Wilcox [this message]
2023-08-21  1:13   ` Peter Xu
2023-08-21  2:29     ` Matthew Wilcox
2023-08-21 16:48       ` Peter Xu
2023-08-22 15:18         ` Matthew Wilcox

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