From: Jason Gunthorpe <jgg@nvidia.com>
To: David Hildenbrand <david@redhat.com>
Cc: Peter Xu <peterx@redhat.com>, Yan Zhao <yan.y.zhao@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alex Williamson <alex.williamson@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
"x86@kernel.org" <x86@kernel.org>,
"Tian, Kevin" <kevin.tian@intel.com>,
Pei Li <peili.dev@gmail.com>, David Wang <00107082@163.com>,
Bert Karwatzki <spasswolf@web.de>,
Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: [PATCH] mm/x86/pat: Only untrack the pfn range if unmap region
Date: Tue, 23 Jul 2024 18:44:12 -0300 [thread overview]
Message-ID: <20240723214412.GQ3371438@nvidia.com> (raw)
In-Reply-To: <f48c1a91-8ed1-447d-93ad-449f28753c5c@redhat.com>
On Tue, Jul 23, 2024 at 11:36:51PM +0200, David Hildenbrand wrote:
> I wonder if we could just let relevant users do the PAT handling manually:
> I'm also not sure how many remap_pfn_range users end up triggering VM_PAT
> code although they don't really have to (just because they happen to cover a
> full VMA)?
>
> One nasty thing is fork(), I was wondering if relevant users really rely on
> that or if we could force these VMAs to simply not get copied during fork.
> During fork() we have to "duplicate" the reservation ...
I admit I barely understand what x86 uses this PAT stuff for -
allowing WC mappings is part of it?
If yes, then RDMA would expect WC PFN MAP VMAs to copy their WCness
during fork..
Jason
next prev parent reply other threads:[~2024-07-23 21:44 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-12 14:42 [PATCH] mm/x86/pat: Only untrack the pfn range if unmap region Peter Xu
2024-07-13 1:18 ` David Hildenbrand
2024-07-13 3:36 ` David Wang
2024-07-14 10:59 ` David Wang
2024-07-14 18:27 ` [PATCH] " David Hildenbrand
2024-07-15 15:03 ` Peter Xu
2024-07-17 14:14 ` David Hildenbrand
2024-07-17 16:27 ` Peter Xu
2024-07-15 7:08 ` Yan Zhao
2024-07-15 14:29 ` Peter Xu
2024-07-16 9:13 ` Yan Zhao
2024-07-16 19:01 ` Peter Xu
2024-07-17 1:38 ` Yan Zhao
2024-07-17 14:15 ` Peter Xu
2024-07-18 1:50 ` Yan Zhao
2024-07-18 14:03 ` Peter Xu
2024-07-18 23:18 ` Yan Zhao
2024-07-19 8:28 ` David Hildenbrand
2024-07-19 14:13 ` Peter Xu
2024-07-22 6:49 ` Yan Zhao
2024-07-22 13:52 ` Peter Xu
2024-07-22 6:43 ` Yan Zhao
2024-07-22 9:17 ` David Hildenbrand
2024-07-23 20:27 ` Peter Xu
2024-07-23 21:36 ` David Hildenbrand
2024-07-23 21:44 ` Jason Gunthorpe [this message]
2024-07-24 8:53 ` David Hildenbrand
2024-07-17 14:17 ` David Hildenbrand
2024-07-17 16:30 ` Peter Xu
2024-07-17 16:31 ` Jason Gunthorpe
2024-07-17 18:10 ` Peter Xu
2024-07-17 16:32 ` David Hildenbrand
2024-07-17 18:12 ` Peter Xu
2024-07-20 2:18 ` Liam R. Howlett
2024-07-22 15:15 ` Peter Xu
2024-07-22 20:22 ` Liam R. Howlett
2024-07-22 21:17 ` Peter Xu
2024-07-23 10:12 ` David Hildenbrand
2024-07-23 17:58 ` Liam R. Howlett
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