From: Jason Gunthorpe <jgg@ziepe.ca>
To: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
John Hubbard <jhubbard@nvidia.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-arch <linux-arch@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Russell King <linux@armlinux.org.uk>,
Mike Rapoport <rppt@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, Jeff Dike <jdike@addtoit.com>,
Richard Weinberger <richard@nod.at>,
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>,
Arnd Bergmann <arnd@arndb.de>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
linux-x86 <x86@kernel.org>,
linux-arm <linux-arm-kernel@lists.infradead.org>,
linux-power <linuxppc-dev@lists.ozlabs.org>,
linux-sparc <sparclinux@vger.kernel.org>,
linux-um <linux-um@lists.infradead.org>,
linux-s390 <linux-s390@vger.kernel.org>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>
Subject: Re: [RFC PATCH v2 1/3] mm/gup: fix gup_fast with dynamic page table folding
Date: Wed, 9 Sep 2020 15:03:24 -0300 [thread overview]
Message-ID: <20200909180324.GI87483@ziepe.ca> (raw)
In-Reply-To: <20200909192534.442f8984@thinkpad>
On Wed, Sep 09, 2020 at 07:25:34PM +0200, Gerald Schaefer wrote:
> I actually had to draw myself a picture to get some hold of
> this, or rather a walk-through with a certain pud-crossing
> range in a folded 3-level scenario. Not sure if I would have
> understood my explanation above w/o that, but I hope you can
> make some sense out of it. Or draw yourself a picture :-)
What I don't understand is how does anything work with S390 today?
If the fix is only to change pxx_addr_end() then than generic code
like mm/pagewalk.c will iterate over a *different list* of page table
entries.
It's choice of entries to look at is entirely driven by pxx_addr_end().
Which suggest to me that mm/pagewalk.c also doesn't work properly
today on S390 and this issue is not really about stack variables?
Fundamentally if pXX_offset() and pXX_addr_end() must be consistent
together, if pXX_offset() is folded then pXX_addr_end() must cause a
single iteration of that level.
Jason
next prev parent reply other threads:[~2020-09-09 18:03 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 18:00 [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Gerald Schaefer
2020-09-07 18:00 ` [RFC PATCH v2 1/3] " Gerald Schaefer
2020-09-08 5:06 ` Christophe Leroy
2020-09-08 12:09 ` Christian Borntraeger
2020-09-08 12:40 ` Christophe Leroy
2020-09-08 13:38 ` Gerald Schaefer
2020-09-08 14:30 ` Dave Hansen
2020-09-08 17:59 ` Gerald Schaefer
2020-09-09 12:29 ` Gerald Schaefer
2020-09-09 16:18 ` Dave Hansen
2020-09-09 17:25 ` Gerald Schaefer
2020-09-09 18:03 ` Jason Gunthorpe [this message]
2020-09-10 9:39 ` Alexander Gordeev
2020-09-10 13:02 ` Jason Gunthorpe
2020-09-10 13:28 ` Gerald Schaefer
2020-09-10 15:10 ` Jason Gunthorpe
2020-09-10 17:07 ` Gerald Schaefer
2020-09-10 17:19 ` Jason Gunthorpe
2020-09-10 17:57 ` Gerald Schaefer
2020-09-10 23:21 ` Jason Gunthorpe
2020-09-10 17:35 ` Linus Torvalds
2020-09-10 18:13 ` Jason Gunthorpe
2020-09-10 18:33 ` Linus Torvalds
2020-09-10 19:10 ` Gerald Schaefer
2020-09-10 19:32 ` Linus Torvalds
2020-09-10 21:59 ` Jason Gunthorpe
2020-09-11 7:09 ` peterz
2020-09-11 11:19 ` Jason Gunthorpe
2020-09-11 19:03 ` [PATCH] " Vasily Gorbik
2020-09-11 19:09 ` Linus Torvalds
2020-09-11 19:40 ` Jason Gunthorpe
2020-09-11 20:05 ` Jason Gunthorpe
2020-09-11 20:36 ` [PATCH v2] " Vasily Gorbik
2020-09-15 17:09 ` Vasily Gorbik
2020-09-15 17:14 ` Jason Gunthorpe
2020-09-15 17:18 ` Mike Rapoport
2020-09-15 17:31 ` John Hubbard
2020-09-10 21:22 ` [RFC PATCH v2 1/3] " John Hubbard
2020-09-10 22:11 ` Jason Gunthorpe
2020-09-10 22:17 ` John Hubbard
2020-09-11 12:19 ` Alexander Gordeev
2020-09-11 16:45 ` Linus Torvalds
2020-09-10 13:11 ` Gerald Schaefer
2020-09-07 18:00 ` [RFC PATCH v2 2/3] mm: make pXd_addr_end() functions page-table entry aware Gerald Schaefer
2020-09-08 5:14 ` Christophe Leroy
2020-09-08 7:46 ` Alexander Gordeev
2020-09-08 8:16 ` Christophe Leroy
2020-09-08 14:15 ` Alexander Gordeev
2020-09-09 8:38 ` Christophe Leroy
2020-09-08 14:25 ` Alexander Gordeev
2020-09-08 13:26 ` Jason Gunthorpe
2020-09-08 14:33 ` Dave Hansen
2020-09-07 18:00 ` [RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions Gerald Schaefer
2020-09-07 20:15 ` Mike Rapoport
2020-09-08 5:19 ` Christophe Leroy
2020-09-08 15:48 ` Alexander Gordeev
2020-09-08 17:20 ` Christophe Leroy
2020-09-07 20:12 ` [RFC PATCH v2 0/3] mm/gup: fix gup_fast with dynamic page table folding Mike Rapoport
2020-09-08 5:22 ` Christophe Leroy
2020-09-08 17:36 ` Gerald Schaefer
2020-09-09 16:12 ` Gerald Schaefer
2020-09-08 4:42 ` Christophe Leroy
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