From: Ram Pai <linuxram@us.ibm.com>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com,
dave.hansen@intel.com, hbabu@us.ibm.com, arnd@arndb.de,
akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com
Subject: Re: [RFC v5 00/38] powerpc: Memory Protection Keys
Date: Mon, 10 Jul 2017 10:15:36 -0700 [thread overview]
Message-ID: <20170710171536.GA5716@ram.oc3035372033.ibm.com> (raw)
In-Reply-To: <20170710060544.GF5713@ram.oc3035372033.ibm.com>
On Sun, Jul 09, 2017 at 11:05:44PM -0700, Ram Pai wrote:
> On Mon, Jul 10, 2017 at 11:13:23AM +0530, Anshuman Khandual wrote:
> > On 07/06/2017 02:51 AM, Ram Pai wrote:
.....
>
> > do you have data points to show the difference in
> > performance between this version and the last one where
> > we skipped the bits from PTE and directly programmed the
> > HPTE entries looking into VMA bits.
>
> No. I dont. I am hoping you can help me out with this.
Anshuman,
The last version where we skipped the PTE bits is guaranteed
to be bad/horrible. For one it has a bug, since it accesses
the vma without a lock. And even if we did take a lock, it
will slow down the page-hash path un-acceptably. So there is
no point measuring the performance of that design.
I think the number we want to measure is -- the performance
with the current design and comparing that to the performance
without memkey feature. We want to find if there is
any degradation by adding this feature.
RP
next prev parent reply other threads:[~2017-07-10 17:15 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-05 21:21 [RFC v5 00/38] powerpc: Memory Protection Keys Ram Pai
2017-07-05 21:21 ` [RFC v5 01/38] powerpc: Free up four 64K PTE bits in 4K backed HPTE pages Ram Pai
2017-07-07 7:25 ` Balbir Singh
2017-07-05 21:21 ` [RFC v5 02/38] powerpc: Free up four 64K PTE bits in 64K " Ram Pai
2017-07-11 5:59 ` Balbir Singh
2017-07-11 15:44 ` Ram Pai
2017-07-12 3:10 ` Balbir Singh
2017-07-13 7:39 ` Ram Pai
2017-07-05 21:21 ` [RFC v5 03/38] powerpc: introduce pte_set_hash_slot() helper Ram Pai
2017-07-05 21:21 ` [RFC v5 04/38] powerpc: introduce pte_get_hash_gslot() helper Ram Pai
2017-07-05 21:21 ` [RFC v5 05/38] powerpc: capture the PTE format changes in the dump pte report Ram Pai
2017-07-05 21:21 ` [RFC v5 06/38] powerpc: use helper functions in __hash_page_64K() for 64K PTE Ram Pai
2017-07-05 21:21 ` [RFC v5 07/38] powerpc: use helper functions in __hash_page_huge() " Ram Pai
2017-07-05 21:21 ` [RFC v5 08/38] powerpc: use helper functions in __hash_page_4K() " Ram Pai
2017-07-05 21:21 ` [RFC v5 09/38] powerpc: use helper functions in __hash_page_4K() for 4K PTE Ram Pai
2017-07-05 21:21 ` [RFC v5 10/38] powerpc: use helper functions in flush_hash_page() Ram Pai
2017-07-05 21:21 ` [RFC v5 11/38] mm: introduce an additional vma bit for powerpc pkey Ram Pai
2017-07-11 18:10 ` Dave Hansen
2017-07-12 22:23 ` Ram Pai
2017-07-12 22:40 ` Benjamin Herrenschmidt
2017-07-05 21:21 ` [RFC v5 12/38] mm: ability to disable execute permission on a key at creation Ram Pai
2017-07-11 18:11 ` Dave Hansen
2017-07-11 21:29 ` Benjamin Herrenschmidt
2017-07-11 21:51 ` Ram Pai
2017-07-11 21:57 ` Dave Hansen
2017-07-11 22:14 ` Ram Pai
2017-07-11 22:19 ` Dave Hansen
2017-07-11 22:08 ` Benjamin Herrenschmidt
2017-07-11 22:19 ` Ram Pai
2017-07-05 21:21 ` [RFC v5 13/38] x86: disallow pkey creation with PKEY_DISABLE_EXECUTE Ram Pai
2017-07-11 18:12 ` Dave Hansen
2017-07-05 21:21 ` [RFC v5 14/38] powerpc: initial plumbing for key management Ram Pai
2017-07-12 3:28 ` Balbir Singh
2017-07-13 7:45 ` Ram Pai
2017-07-13 20:37 ` Ram Pai
2017-07-13 21:30 ` Balbir Singh
2017-07-05 21:21 ` [RFC v5 15/38] powerpc: helper function to read,write AMR,IAMR,UAMOR registers Ram Pai
2017-07-12 5:26 ` Balbir Singh
2017-07-13 7:55 ` Ram Pai
2017-07-13 9:49 ` Balbir Singh
2017-07-13 23:29 ` Ram Pai
2017-07-05 21:21 ` [RFC v5 16/38] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2017-07-05 21:21 ` [RFC v5 17/38] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2017-07-05 21:21 ` [RFC v5 18/38] powerpc: store and restore the pkey state across context switches Ram Pai
2017-07-05 21:21 ` [RFC v5 19/38] powerpc: introduce execute-only pkey Ram Pai
2017-07-05 21:21 ` [RFC v5 20/38] powerpc: ability to associate pkey to a vma Ram Pai
2017-07-05 21:21 ` [RFC v5 21/38] powerpc: implementation for arch_override_mprotect_pkey() Ram Pai
2017-07-05 21:21 ` [RFC v5 22/38] powerpc: map vma key-protection bits to pte key bits Ram Pai
2017-07-05 21:22 ` [RFC v5 23/38] powerpc: sys_pkey_mprotect() system call Ram Pai
2017-07-05 21:22 ` [RFC v5 24/38] powerpc: Program HPTE key protection bits Ram Pai
2017-07-05 21:22 ` [RFC v5 25/38] powerpc: helper to validate key-access permissions of a pte Ram Pai
2017-07-05 21:22 ` [RFC v5 26/38] powerpc: check key protection for user page access Ram Pai
2017-07-05 21:22 ` [RFC v5 27/38] powerpc: Macro the mask used for checking DSI exception Ram Pai
2017-07-05 21:22 ` [RFC v5 28/38] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2017-07-05 21:22 ` [RFC v5 29/38] powerpc: Handle exceptions caused by pkey violation Ram Pai
2017-07-05 21:22 ` [RFC v5 30/38] powerpc: capture AMR register content on " Ram Pai
2017-07-05 21:22 ` [RFC v5 31/38] powerpc: introduce get_pte_pkey() helper Ram Pai
2017-07-10 3:11 ` Anshuman Khandual
2017-07-10 5:55 ` Ram Pai
2017-07-11 11:22 ` Anshuman Khandual
2017-07-05 21:22 ` [RFC v5 32/38] powerpc: capture the violated protection key on fault Ram Pai
2017-07-10 3:10 ` Anshuman Khandual
2017-07-10 5:49 ` Ram Pai
2017-07-05 21:22 ` [RFC v5 33/38] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2017-07-10 3:08 ` Anshuman Khandual
2017-07-05 21:22 ` [RFC v5 34/38] procfs: display the protection-key number associated with a vma Ram Pai
2017-07-10 3:07 ` Anshuman Khandual
2017-07-10 6:01 ` Ram Pai
2017-07-11 18:13 ` Dave Hansen
2017-07-13 8:03 ` Ram Pai
2017-07-13 14:07 ` Dave Hansen
2017-07-13 17:04 ` Ram Pai
2017-07-05 21:22 ` [RFC v5 35/38] selftest: Move protecton key selftest to arch neutral directory Ram Pai
2017-07-05 21:22 ` [RFC v5 36/38] selftest: PowerPC specific test updates to memory protection keys Ram Pai
2017-07-11 17:33 ` Dave Hansen
2017-07-12 21:57 ` Ram Pai
2017-07-05 21:22 ` [RFC v5 37/38] Documentation: Move protecton key documentation to arch neutral directory Ram Pai
2017-07-05 21:22 ` [RFC v5 38/38] Documentation: PowerPC specific updates to memory protection keys Ram Pai
2017-07-10 3:07 ` Anshuman Khandual
2017-07-10 5:59 ` Ram Pai
2017-07-11 18:23 ` Dave Hansen
2017-07-13 19:56 ` Ram Pai
2017-07-10 5:43 ` [RFC v5 00/38] powerpc: Memory Protection Keys Anshuman Khandual
2017-07-10 6:05 ` Ram Pai
2017-07-10 17:15 ` Ram Pai [this message]
2017-07-11 14:52 ` Michal Hocko
2017-07-11 19:32 ` Ram Pai
2017-07-11 21:30 ` Benjamin Herrenschmidt
2017-07-12 7:23 ` Michal Hocko
2017-07-12 7:39 ` Michal Hocko
2017-07-12 22:53 ` Benjamin Herrenschmidt
2017-07-13 6:20 ` Michal Hocko
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