Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757914AbaKTKZy (ORCPT ); Thu, 20 Nov 2014 05:25:54 -0500 Received: from cantor2.suse.de ([195.135.220.15]:50264 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751575AbaKTKT4 (ORCPT ); Thu, 20 Nov 2014 05:19:56 -0500 From: Mel Gorman To: Linux Kernel Cc: Linux-MM , LinuxPPC-dev , Aneesh Kumar , Hugh Dickins , Dave Jones , Rik van Riel , Ingo Molnar , Kirill Shutemov , Sasha Levin , Benjamin Herrenschmidt , Paul Mackerras , Linus Torvalds , Mel Gorman Subject: [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v2 Date: Thu, 20 Nov 2014 10:19:40 +0000 Message-Id: <1416478790-27522-1-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org V1 failed while running under kvm-tools very quickly and a second report indicated that it happens on bare metal as well. This version survived an overnight run of trinity running under kvm-tools here but verification from Sasha would be appreciated. Changelog since V1 o ppc64 paranoia checks and clarifications (aneesh) o Fix trinity regression (hopefully) o Reduce unnecessary TLB flushes (mel) Automatic NUMA balancing depends on being able to protect PTEs to trap a fault and gather reference locality information. Very broadly speaking it would mark PTEs as not present and use another bit to distinguish between NUMA hinting faults and other types of faults. It was universally loved by everybody and caused no problems whatsoever. That last sentence might be a lie. This series is very heavily based on patches from Linus and Aneesh to replace the existing PTE/PMD NUMA helper functions with normal change protections. I did alter and add parts of it but I consider them relatively minor contributions. At their suggestion, acked-bys are in there but I've no problem converting them to Signed-off-by if requested. AFAIK, this has received no testing on ppc64 and I'm depending on Aneesh for that. I tested trinity under kvm-tool and passed and ran a few other basic tests. In most cases I'm leaving out detail as it's not that interesting. specjbb single JVM: There was negligible performance difference in the benchmark itself for short and long runs. However, system activity is higher and interrupts are much higher over time -- possibly TLB flushes. Migrations are also higher. Overall, this is more overhead but considering the problems faced with the old approach I think we just have to suck it up and find another way of reducing the overhead. specjbb multi JVM: Negligible performance difference to the actual benchmarm but like the single JVM case, the system overhead is noticably higher. Again, interrupts are a major factor. autonumabench: This was all over the place and about all that can be reasonably concluded is that it's different but not necessarily better or worse. autonumabench 3.18.0-rc4 3.18.0-rc4 vanilla protnone-v2r5 User NUMA01 32806.01 ( 0.00%) 20250.67 ( 38.27%) User NUMA01_THEADLOCAL 23910.28 ( 0.00%) 22734.37 ( 4.92%) User NUMA02 3176.85 ( 0.00%) 3082.68 ( 2.96%) User NUMA02_SMT 1600.06 ( 0.00%) 1547.08 ( 3.31%) System NUMA01 719.07 ( 0.00%) 1344.39 (-86.96%) System NUMA01_THEADLOCAL 916.26 ( 0.00%) 180.90 ( 80.26%) System NUMA02 20.92 ( 0.00%) 17.34 ( 17.11%) System NUMA02_SMT 8.76 ( 0.00%) 7.24 ( 17.35%) Elapsed NUMA01 728.27 ( 0.00%) 519.28 ( 28.70%) Elapsed NUMA01_THEADLOCAL 589.15 ( 0.00%) 554.73 ( 5.84%) Elapsed NUMA02 81.20 ( 0.00%) 81.72 ( -0.64%) Elapsed NUMA02_SMT 80.49 ( 0.00%) 79.58 ( 1.13%) CPU NUMA01 4603.00 ( 0.00%) 4158.00 ( 9.67%) CPU NUMA01_THEADLOCAL 4213.00 ( 0.00%) 4130.00 ( 1.97%) CPU NUMA02 3937.00 ( 0.00%) 3793.00 ( 3.66%) CPU NUMA02_SMT 1998.00 ( 0.00%) 1952.00 ( 2.30%) System CPU usage of NUMA01 is worse but it's an adverse workload on this machine so I'm reluctant to conclude that it's a problem that matters. On the other workloads that are sensible on this machine, system CPU usage is great. Overall time to complete the benchmark is comparable 3.18.0-rc4 3.18.0-rc4 vanillaprotnone-v2r5 User 61493.38 47615.01 System 1665.17 1550.07 Elapsed 1480.79 1236.74 NUMA alloc hit 4739774 5328362 NUMA alloc miss 0 0 NUMA interleave hit 0 0 NUMA alloc local 4664980 5328351 NUMA base PTE updates 556489407 444119981 NUMA huge PMD updates 1086000 866680 NUMA page range updates 1112521407 887860141 NUMA hint faults 1538964 1242142 NUMA hint local faults 835871 814313 NUMA hint local percent 54 65 NUMA pages migrated 7329212 59883854 The NUMA pages migrated look terrible but when I looked at a graph of the activity over time I see that the massive spike in migration activity was during NUMA01. This correlates with high system CPU usage and could be simply down to bad luck but any modifications that affect that workload would be related to scan rates and migrations, not the protection mechanism. For all other workloads, migration activity was comparable. Overall, headline performance figures are comparable but the overhead is higher, mostly in interrupts. To some extent, higher overhead from this approach was anticipated but not to this degree. It's going to be necessary to reduce this again with a separate series in the future. It's still worth going ahead with this series though as it's likely to avoid constant headaches with Xen and is probably easier to maintain. arch/powerpc/include/asm/pgtable.h | 53 ++---------- arch/powerpc/include/asm/pte-common.h | 5 -- arch/powerpc/include/asm/pte-hash64.h | 6 -- arch/powerpc/kvm/book3s_hv_rm_mmu.c | 2 +- arch/powerpc/mm/copro_fault.c | 8 +- arch/powerpc/mm/fault.c | 25 ++---- arch/powerpc/mm/gup.c | 4 +- arch/powerpc/mm/pgtable.c | 8 +- arch/powerpc/mm/pgtable_64.c | 3 +- arch/x86/include/asm/pgtable.h | 46 +++++----- arch/x86/include/asm/pgtable_64.h | 5 -- arch/x86/include/asm/pgtable_types.h | 41 +-------- arch/x86/mm/gup.c | 4 +- include/asm-generic/pgtable.h | 152 ++-------------------------------- include/linux/migrate.h | 4 - include/linux/swapops.h | 2 +- include/uapi/linux/mempolicy.h | 2 +- mm/gup.c | 8 +- mm/huge_memory.c | 50 ++++++----- mm/memory.c | 18 ++-- mm/mempolicy.c | 2 +- mm/migrate.c | 8 +- mm/mprotect.c | 48 +++++------ mm/pgtable-generic.c | 2 - 24 files changed, 131 insertions(+), 375 deletions(-) -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/