From: Vineet Gupta <Vineet.Gupta1@synopsys.com> To: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Catalin Marinas <catalin.marinas@arm.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>, Vlastimil Babka <vbabka@suse.cz>, Russell King <linux@armlinux.org.uk>, Will Deacon <will.deacon@arm.com>, Ralf Baechle <ralf@linux-mips.org>, "David S. Miller" <davem@davemloft.net>, "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Andrea Arcangeli <aarcange@redhat.com>, "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de> Subject: Re: [PATCHv2 1/3] x86/mm: Provide pmdp_establish() helper Date: Wed, 21 Jun 2017 10:20:47 -0700 [thread overview] Message-ID: <eeff42d2-fc4b-ea9c-81d2-145fb349f420@synopsys.com> (raw) In-Reply-To: <20170621171558.7zrgzc7uk3kspcys@node.shutemov.name> On 06/21/2017 10:16 AM, Kirill A. Shutemov wrote: > On Wed, Jun 21, 2017 at 08:49:03AM -0700, Vineet Gupta wrote: >> On 06/21/2017 04:27 AM, Catalin Marinas wrote: >>> On Wed, Jun 21, 2017 at 12:53:03PM +0300, Kirill A. Shutemov wrote: >>>>>>>>> On Thu, Jun 15, 2017 at 05:52:22PM +0300, Kirill A. Shutemov wrote: >>>>>>>>>> We need an atomic way to setup pmd page table entry, avoiding races with >>>>>>>>>> CPU setting dirty/accessed bits. This is required to implement >>>>>>>>>> pmdp_invalidate() that doesn't loose these bits. >>> [...] >>>> Any chance you could help me with arm too? >>> On arm (ARMv7 with LPAE) we don't have hardware updates of the >>> access/dirty bits, so a generic implementation would suffice. I didn't >>> find one in your patches, so here's an untested version: >>> >>> static inline pmd_t pmdp_establish(struct mm_struct *mm, unsigned long address, >>> pmd_t *pmdp, pmd_t pmd) >>> { >>> pmd_t old_pmd = *pmdp; >>> set_pmd_at(mm, address, pmdp, pmd); >>> return old_pmd; >>> } >> So it seems the discussions have settled down and pmdp_establish() can be >> implemented in generic way as above and it will suffice if arch doesn't have >> a special need. It would be nice to add the comment above generic version >> that it only needs to be implemented if hardware sets the accessed/dirty >> bits ! >> >> Then nothing special is needed for ARC - right ? > I will define generic version as Catalin proposed with a comment, but > under the name generic_pmdp_establish. An arch can make use of it by > > #define pmdp_establish generic_pmdp_establish Can you do that for ARC in your next posting - or want me to once you have posted that ? > I don't want it to be used by default without attention from architecture > maintainer. It can lead unnoticied breakage if THP got enabled on new > arch. Makes sense ! -Vineet
WARNING: multiple messages have this Message-ID (diff)
From: Vineet Gupta <Vineet.Gupta1@synopsys.com> To: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Catalin Marinas <catalin.marinas@arm.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>, Vlastimil Babka <vbabka@suse.cz>, Russell King <linux@armlinux.org.uk>, Will Deacon <will.deacon@arm.com>, Ralf Baechle <ralf@linux-mips.org>, "David S. Miller" <davem@davemloft.net>, "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Andrea Arcangeli <aarcange@redhat.com>, "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de> Subject: Re: [PATCHv2 1/3] x86/mm: Provide pmdp_establish() helper Date: Wed, 21 Jun 2017 10:20:47 -0700 [thread overview] Message-ID: <eeff42d2-fc4b-ea9c-81d2-145fb349f420@synopsys.com> (raw) In-Reply-To: <20170621171558.7zrgzc7uk3kspcys@node.shutemov.name> On 06/21/2017 10:16 AM, Kirill A. Shutemov wrote: > On Wed, Jun 21, 2017 at 08:49:03AM -0700, Vineet Gupta wrote: >> On 06/21/2017 04:27 AM, Catalin Marinas wrote: >>> On Wed, Jun 21, 2017 at 12:53:03PM +0300, Kirill A. Shutemov wrote: >>>>>>>>> On Thu, Jun 15, 2017 at 05:52:22PM +0300, Kirill A. Shutemov wrote: >>>>>>>>>> We need an atomic way to setup pmd page table entry, avoiding races with >>>>>>>>>> CPU setting dirty/accessed bits. This is required to implement >>>>>>>>>> pmdp_invalidate() that doesn't loose these bits. >>> [...] >>>> Any chance you could help me with arm too? >>> On arm (ARMv7 with LPAE) we don't have hardware updates of the >>> access/dirty bits, so a generic implementation would suffice. I didn't >>> find one in your patches, so here's an untested version: >>> >>> static inline pmd_t pmdp_establish(struct mm_struct *mm, unsigned long address, >>> pmd_t *pmdp, pmd_t pmd) >>> { >>> pmd_t old_pmd = *pmdp; >>> set_pmd_at(mm, address, pmdp, pmd); >>> return old_pmd; >>> } >> So it seems the discussions have settled down and pmdp_establish() can be >> implemented in generic way as above and it will suffice if arch doesn't have >> a special need. It would be nice to add the comment above generic version >> that it only needs to be implemented if hardware sets the accessed/dirty >> bits ! >> >> Then nothing special is needed for ARC - right ? > I will define generic version as Catalin proposed with a comment, but > under the name generic_pmdp_establish. An arch can make use of it by > > #define pmdp_establish generic_pmdp_establish Can you do that for ARC in your next posting - or want me to once you have posted that ? > I don't want it to be used by default without attention from architecture > maintainer. It can lead unnoticied breakage if THP got enabled on new > arch. Makes sense ! -Vineet -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-06-21 17:21 UTC|newest] Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-06-15 14:52 [HELP-NEEDED, PATCHv2 0/3] Do not loose dirty bit on THP pages Kirill A. Shutemov 2017-06-15 14:52 ` Kirill A. Shutemov 2017-06-15 14:52 ` [PATCHv2 1/3] x86/mm: Provide pmdp_establish() helper Kirill A. Shutemov 2017-06-15 14:52 ` Kirill A. Shutemov 2017-06-16 13:36 ` Andrea Arcangeli 2017-06-16 13:36 ` Andrea Arcangeli 2017-06-19 12:46 ` Kirill A. Shutemov 2017-06-19 12:46 ` Kirill A. Shutemov 2017-06-19 5:48 ` Martin Schwidefsky 2017-06-19 5:48 ` Martin Schwidefsky 2017-06-19 5:48 ` Martin Schwidefsky 2017-06-19 5:48 ` Martin Schwidefsky 2017-06-19 12:48 ` Kirill A. Shutemov 2017-06-19 12:48 ` Kirill A. Shutemov 2017-06-19 13:04 ` Martin Schwidefsky 2017-06-19 13:04 ` Martin Schwidefsky 2017-06-19 15:22 ` Catalin Marinas 2017-06-19 15:22 ` Catalin Marinas 2017-06-19 16:00 ` Kirill A. Shutemov 2017-06-19 16:00 ` Kirill A. Shutemov 2017-06-19 17:09 ` Catalin Marinas 2017-06-19 17:09 ` Catalin Marinas 2017-06-19 21:52 ` Kirill A. Shutemov 2017-06-19 21:52 ` Kirill A. Shutemov 2017-06-20 15:54 ` Catalin Marinas 2017-06-20 15:54 ` Catalin Marinas 2017-06-21 9:53 ` Kirill A. Shutemov 2017-06-21 9:53 ` Kirill A. Shutemov 2017-06-21 10:40 ` Catalin Marinas 2017-06-21 10:40 ` Catalin Marinas 2017-06-21 11:27 ` Catalin Marinas 2017-06-21 11:27 ` Catalin Marinas 2017-06-21 12:04 ` Kirill A. Shutemov 2017-06-21 12:04 ` Kirill A. Shutemov 2017-06-21 15:49 ` Vineet Gupta 2017-06-21 15:49 ` Vineet Gupta 2017-06-21 17:15 ` Kirill A. Shutemov 2017-06-21 17:15 ` Kirill A. Shutemov 2017-06-21 17:20 ` Vineet Gupta [this message] 2017-06-21 17:20 ` Vineet Gupta 2017-06-21 17:52 ` Kirill A. Shutemov 2017-06-21 17:52 ` Kirill A. Shutemov 2017-06-21 17:52 ` Kirill A. Shutemov 2017-06-19 17:11 ` Nadav Amit 2017-06-19 17:11 ` Nadav Amit 2017-06-19 21:57 ` Kirill A. Shutemov 2017-06-19 21:57 ` Kirill A. Shutemov 2017-06-15 14:52 ` [PATCHv2 2/3] mm: Do not loose dirty and access bits in pmdp_invalidate() Kirill A. Shutemov 2017-06-15 14:52 ` Kirill A. Shutemov 2017-06-15 22:44 ` kbuild test robot 2017-06-15 22:44 ` kbuild test robot 2017-06-15 22:44 ` kbuild test robot 2017-06-16 13:40 ` Andrea Arcangeli 2017-06-16 13:40 ` Andrea Arcangeli 2017-06-19 13:29 ` Kirill A. Shutemov 2017-06-19 13:29 ` Kirill A. Shutemov 2017-06-15 14:52 ` [PATCHv2 3/3] mm: Use updated pmdp_invalidate() inteface to track dirty/accessed bits Kirill A. Shutemov 2017-06-15 14:52 ` Kirill A. Shutemov 2017-06-15 21:54 ` kbuild test robot 2017-06-15 21:54 ` kbuild test robot 2017-06-15 21:54 ` kbuild test robot 2017-06-15 23:02 ` kbuild test robot 2017-06-15 23:02 ` kbuild test robot 2017-06-15 23:02 ` kbuild test robot 2017-06-16 3:02 ` Minchan Kim 2017-06-16 3:02 ` Minchan Kim 2017-06-16 13:19 ` Kirill A. Shutemov 2017-06-16 13:19 ` Kirill A. Shutemov 2017-06-16 13:52 ` Minchan Kim 2017-06-16 13:52 ` Minchan Kim 2017-06-16 14:27 ` Andrea Arcangeli 2017-06-16 14:27 ` Andrea Arcangeli 2017-06-16 14:53 ` Minchan Kim 2017-06-16 14:53 ` Minchan Kim 2017-06-19 14:03 ` Kirill A. Shutemov 2017-06-19 14:03 ` Kirill A. Shutemov 2017-06-20 2:52 ` Minchan Kim 2017-06-20 2:52 ` Minchan Kim 2017-06-20 9:57 ` Minchan Kim 2017-06-20 9:57 ` Minchan Kim 2017-06-16 11:31 ` Aneesh Kumar K.V 2017-06-16 11:31 ` Aneesh Kumar K.V 2017-06-16 11:31 ` Aneesh Kumar K.V 2017-06-16 11:31 ` Aneesh Kumar K.V 2017-06-16 13:21 ` Kirill A. Shutemov 2017-06-16 13:21 ` Kirill A. Shutemov 2017-06-16 15:57 ` Aneesh Kumar K.V 2017-06-16 15:57 ` Aneesh Kumar K.V
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