From: Dave Hansen <dave.hansen@intel.com>
To: Peter Xu <peterx@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Jason Gunthorpe <jgg@nvidia.com>,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Dan Williams <dan.j.williams@intel.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Mike Rapoport <rppt@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Michal Hocko <mhocko@suse.com>,
Alex Williamson <alex.williamson@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Suren Baghdasaryan <surenb@google.com>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org
Subject: Re: [PATCH RFC 2/2] mm/x86/pat: Do proper PAT bit shift for large mappings
Date: Thu, 23 May 2024 20:30:19 -0700 [thread overview]
Message-ID: <7b6b6430-0237-4512-b99b-9eb815b3dc68@intel.com> (raw)
In-Reply-To: <Zk_MGmfYsY9dt2Uo@x1n>
On 5/23/24 16:07, Peter Xu wrote:
> Probably not.. I think I can define a pgprot_to_large() globally, pointing
> that to pgprot_4k_2_large() on x86 and make the fallback to be noop. And
> if there's a new version I'll guarantee to run over my cross compilers.
I guess that would be functional, but it would be a bit mean to
everybody else.
> Any comments on the idea itself? Do we have a problem, or maybe I
> overlooked something?
I think it's probably unnecessary to inflict this particular x86-ism on
generic code. The arch-generic 'prot' should have PAT at its 4k
(_PAGE_BIT_PAT) position and then p*d_mkhuge() can shift it into the
_PAGE_BIT_PAT_LARGE spot.
next prev parent reply other threads:[~2024-05-24 3:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-23 22:37 [PATCH RFC 0/2] mm/x86/pat: Fix two possible issues Peter Xu
2024-05-23 22:37 ` [PATCH RFC 1/2] mm/x86/pat: Only untrack the pfn range if unmap region Peter Xu
2024-05-23 22:37 ` [PATCH RFC 2/2] mm/x86/pat: Do proper PAT bit shift for large mappings Peter Xu
2024-05-23 22:48 ` Dave Hansen
2024-05-23 23:07 ` Peter Xu
2024-05-24 0:53 ` Peter Xu
2024-05-24 3:30 ` Dave Hansen [this message]
2024-05-24 23:55 ` Peter Xu
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