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From: "Huang, Ying" <ying.huang@intel.com>
To: Donet Tom <donettom@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,  linux-mm@kvack.org,
  linux-kernel@vger.kernel.org,  Aneesh Kumar <aneesh.kumar@kernel.org>,
  Michal Hocko <mhocko@kernel.org>,  Dave Hansen
 <dave.hansen@linux.intel.com>,  Mel Gorman <mgorman@suse.de>,  Feng Tang
 <feng.tang@intel.com>,  Andrea Arcangeli <aarcange@redhat.com>,  Peter
 Zijlstra <peterz@infradead.org>,  Ingo Molnar <mingo@redhat.com>,  Rik van
 Riel <riel@surriel.com>,  Johannes Weiner <hannes@cmpxchg.org>,  Matthew
 Wilcox <willy@infradead.org>,  Vlastimil Babka <vbabka@suse.cz>,  Dan
 Williams <dan.j.williams@intel.com>,  Hugh Dickins <hughd@google.com>,
  Kefeng Wang <wangkefeng.wang@huawei.com>,  Suren Baghdasaryan
 <surenb@google.com>
Subject: Re: [PATCH v4 0/2] Allow migrate on protnone reference with
 MPOL_PREFERRED_MANY policy
In-Reply-To: <cover.1711373653.git.donettom@linux.ibm.com> (Donet Tom's
	message of "Mon, 25 Mar 2024 09:24:12 -0500")
References: <cover.1711373653.git.donettom@linux.ibm.com>
Date: Tue, 26 Mar 2024 10:38:00 +0800
Message-ID: <875xx9pvjr.fsf@yhuang6-desk2.ccr.corp.intel.com>
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Donet Tom <donettom@linux.ibm.com> writes:

> This patchset is to optimize the cross-socket memory access with
> MPOL_PREFERRED_MANY policy.
>
> To test this patch we ran the following test on a 3 node system.
>  Node 0 - 2GB   - Tier 1
>  Node 1 - 11GB  - Tier 1
>  Node 6 - 10GB  - Tier 2
>
> Below changes are made to memcached to set the memory policy,
> It select Node0 and Node1 as preferred nodes.
>
>    #include <numaif.h>
>    #include <numa.h>
>
>     unsigned long nodemask;
>     int ret;
>
>     nodemask = 0x03;
>     ret = set_mempolicy(MPOL_PREFERRED_MANY | MPOL_F_NUMA_BALANCING,
>                                                &nodemask, 10);
>     /* If MPOL_F_NUMA_BALANCING isn't supported,
>      * fall back to MPOL_PREFERRED_MANY */
>     if (ret < 0 && errno == EINVAL){
>        printf("set mem policy normal\n");
>         ret = set_mempolicy(MPOL_PREFERRED_MANY, &nodemask, 10);
>     }
>     if (ret < 0) {
>        perror("Failed to call set_mempolicy");
>        exit(-1);
>     }
>
> Test Procedure:
> ===============
> 1. Make sure memory tiering and demotion are enabled.
> 2. Start memcached.
>
>    # ./memcached -b 100000 -m 204800 -u root -c 1000000 -t 7
>        -d -s "/tmp/memcached.sock"
>
> 3. Run memtier_benchmark to store 3200000 keys.
>
>   #./memtier_benchmark -S "/tmp/memcached.sock" --protocol=memcache_binary
>     --threads=1 --pipeline=1 --ratio=1:0 --key-pattern=S:S --key-minimum=1
>     --key-maximum=3200000 -n allkeys -c 1 -R -x 1 -d 1024
>
> 4. Start a memory eater on node 0 and 1. This will demote all memcached
>    pages to node 6.
> 5. Make sure all the memcached pages got demoted to lower tier by reading
>    /proc/<memcaced PID>/numa_maps.
>
>     # cat /proc/2771/numa_maps
>      ---
>     default anon=1009 dirty=1009 active=0 N6=1009 kernelpagesize_kB=64
>     default anon=1009 dirty=1009 active=0 N6=1009 kernelpagesize_kB=64
>      ---
>
> 6. Kill memory eater.
> 7. Read the pgpromote_success counter.
> 8. Start reading the keys by running memtier_benchmark.
>
>   #./memtier_benchmark -S "/tmp/memcached.sock" --protocol=memcache_binary
>    --pipeline=1 --distinct-client-seed --ratio=0:3 --key-pattern=R:R
>    --key-minimum=1 --key-maximum=3200000 -n allkeys
>    --threads=64 -c 1 -R -x 6
>
> 9. Read the pgpromote_success counter.
>
> Test Results:
> =============
> Without Patch
> ------------------
> 1. pgpromote_success  before test
> Node 0:  pgpromote_success 11
> Node 1:  pgpromote_success 140974
>
> pgpromote_success  after test
> Node 0:  pgpromote_success 11
> Node 1:  pgpromote_success 140974
>
> 2. Memtier-benchmark result.
> AGGREGATED AVERAGE RESULTS (6 runs)
> ==================================================================
> Type    Ops/sec   Hits/sec   Misses/sec  Avg. Latency  p50 Latency
> ------------------------------------------------------------------
> Sets     0.00       ---         ---        ---          ---
> Gets    305792.03  305791.93   0.10       0.18949       0.16700
> Waits    0.00       ---         ---        ---          ---
> Totals  305792.03  305791.93   0.10       0.18949       0.16700
>
> ======================================
> p99 Latency  p99.9 Latency  KB/sec
> -------------------------------------
> ---          ---            0.00
> 0.44700     1.71100        11542.69
> ---           ---            ---
> 0.44700     1.71100        11542.69
>
> With Patch
> ---------------
> 1. pgpromote_success  before test
> Node 0:  pgpromote_success 5
> Node 1:  pgpromote_success 89386
>
> pgpromote_success  after test
> Node 0:  pgpromote_success 57895
> Node 1:  pgpromote_success 141463
>
> 2. Memtier-benchmark result.
> AGGREGATED AVERAGE RESULTS (6 runs)
> ====================================================================
> Type    Ops/sec    Hits/sec  Misses/sec  Avg. Latency  p50 Latency
> --------------------------------------------------------------------
> Sets     0.00        ---       ---        ---           ---
> Gets    521942.24  521942.07  0.17       0.11459        0.10300
> Waits    0.00        ---       ---         ---          ---
> Totals  521942.24  521942.07  0.17       0.11459        0.10300
>
> =======================================
> p99 Latency  p99.9 Latency  KB/sec
> ---------------------------------------
>  ---          ---            0.00
> 0.23100      0.31900        19701.68
> ---          ---             ---
> 0.23100      0.31900        19701.68
>
>
> Test Result Analysis:
> =====================
> 1. With patch we could observe pages are getting promoted.
> 2. Memtier-benchmark results shows that, with the patch,
>    performance has increased more than 50%.
>
>  Ops/sec without fix -  305792.03
>  Ops/sec with fix    -  521942.24
>
> Changes:
> V4
> - Added an example in the "PATCH 2/2" commit message as per the discussion
>   from V3.
> V3:
> - Added "* @vmf: structure describing the fault" comment for
>   mpol_misplaced() to fix the warning.
> https://lore.kernel.org/oe-kbuild-all/202403202229.WZeAnUuO-lkp@intel.com/
> -https://lore.kernel.org/lkml/cover.1711002865.git.donettom@linux.ibm.com/
> v2:
> - Rebased on latest upstream (v6.8-rc7)
> - Used 'numa_node_id()' to get the current execution node ID, Added
>   'lockdep_assert_held' to make sure that the 'mpol_misplaced()' is
>   called with ptl held.
> - The migration condition has been updated; now, migration will only
>   occur if the execution node is present in the policy nodemask.
> -https://lore.kernel.org/lkml/cover.1709909210.git.donettom@linux.ibm.com/
>
> -v1: https://lore.kernel.org/linux-mm/9c3f7b743477560d1c5b12b8c111a584a2cc92ee.1708097962.git.donettom@linux.ibm.com/#t
>
>
> Donet Tom (2):
>   mm/mempolicy: Use numa_node_id() instead of cpu_to_node()
>   mm/numa_balancing:Allow migrate on protnone reference with
>     MPOL_PREFERRED_MANY policy
>
>  include/linux/mempolicy.h |  5 +++--
>  mm/huge_memory.c          |  2 +-
>  mm/internal.h             |  2 +-
>  mm/memory.c               |  8 +++++---
>  mm/mempolicy.c            | 36 +++++++++++++++++++++++++++---------
>  5 files changed, 37 insertions(+), 16 deletions(-)

LGTM, Thanks!  Feel free to add

Reviewed-by: "Huang, Ying" <ying.huang@intel.com>

in the future version.

--
Best Regards,
Huang, Ying