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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,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH 0/3] mm/arch: Fix a few collide definition on private use of VM_FAULT_*
Date: Mon, 6 Feb 2023 00:10:53 +0000	[thread overview]
Message-ID: <Y+BFjQDBIFq5ih+t@casper.infradead.org> (raw)
In-Reply-To: <20230205231704.909536-1-peterx@redhat.com>

On Sun, Feb 05, 2023 at 06:17:01PM -0500, Peter Xu wrote:
> I noticed a few collision usage on VM_FAULT_* definition in the page fault
> path on arm/arm64/s390 where the VM_FAULT_* can overlap with the generic
> definition of vm_fault_reason.
> 
> The major overlapped part being VM_FAULT_HINDEX_MASK which is used only by
> the hugetlb hwpoisoning.
> 
> I'm not sure whether any of them can have a real impact, but that does not
> look like to be expected.  I didn't copy stable, if anyone thinks it should
> please shoot.  Nor did I test them in any form - I just changed the
> allocations from top bits and added a comment for each of them.

This seems like a bad way to do it.  Why not just put these VM_FAULT_*
definitions in linux/mm_types.h?  Then we'll see them when adding new
VM_FAULT codes.  Sure, they won't be used by every architecture, but
so what?


  parent reply	other threads:[~2023-02-06  0:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-05 23:17 [PATCH 0/3] mm/arch: Fix a few collide definition on private use of VM_FAULT_* Peter Xu
2023-02-05 23:17 ` [PATCH 1/3] mm/arm: Define private VM_FAULT_* reasons from top bits Peter Xu
2023-02-05 23:17 ` [PATCH 2/3] mm/arm64: " Peter Xu
2023-02-05 23:17 ` [PATCH 3/3] mm/s390: " Peter Xu
2023-02-09 20:10   ` Heiko Carstens
2023-02-06  0:10 ` Matthew Wilcox [this message]
2023-02-06  0:54   ` [PATCH 0/3] mm/arch: Fix a few collide definition on private use of VM_FAULT_* Peter Xu
2023-02-06  2:51     ` Matthew Wilcox
2023-02-06  3:18       ` Peter Xu
2023-02-06  5:09         ` Matthew Wilcox
2023-02-09 20:04           ` Heiko Carstens

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