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 02:51:18 +0000 [thread overview]
Message-ID: <Y+BrJhxeJbAp49QE@casper.infradead.org> (raw)
In-Reply-To: <Y+BPy3jFcHqOnWL0@x1n>
On Sun, Feb 05, 2023 at 07:54:35PM -0500, Peter Xu wrote:
> On Mon, Feb 06, 2023 at 12:10:53AM +0000, Matthew Wilcox wrote:
> > 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?
>
> My initial version actually contains a few VM_FAULT_PRIVATE_N there, but I
That wasn't what I meant. I meant putting VM_FAULT_BADMAP and
VM_FAULT_SIGSEGV in mm_types.h. Not having "Here is a range of reserved
arch private ones".
next prev parent reply other threads:[~2023-02-06 2:51 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 ` [PATCH 0/3] mm/arch: Fix a few collide definition on private use of VM_FAULT_* Matthew Wilcox
2023-02-06 0:54 ` Peter Xu
2023-02-06 2:51 ` Matthew Wilcox [this message]
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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