Re: [RFC -V2 2/8] autonuma, memory tiering: Rate limit NUMA migration throughput

[kbuild test robot <lkp@intel.com>]

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Hi Ying",

[FYI, it's a private test report for your RFC patch.]
[auto build test ERROR on tip/sched/core]
[also build test ERROR on linux/master linus/master v5.6-rc2]
[cannot apply to next-20200219]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Huang-Ying/autonuma-Optimize-memory-placement-in-memory-tiering-system/20200220-044152
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 25ac227a25ac946e0356772012398cd1710a8bab
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=arm64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   kernel//sched/fair.c: In function 'should_numa_migrate_memory':
>> kernel//sched/fair.c:1462:6: error: implicit declaration of function 'next_promotion_node'; did you mean 'next_memory_node'? [-Werror=implicit-function-declaration]
         next_promotion_node(src_nid) != -1) {
         ^~~~~~~~~~~~~~~~~~~
         next_memory_node
   cc1: some warnings being treated as errors

vim +1462 kernel//sched/fair.c

  1449	
  1450	bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
  1451					int src_nid, int dst_cpu)
  1452	{
  1453		struct numa_group *ng = deref_curr_numa_group(p);
  1454		int dst_nid = cpu_to_node(dst_cpu);
  1455		int last_cpupid, this_cpupid;
  1456	
  1457		/*
  1458		 * If memory tiering mode is enabled, will try promote pages
  1459		 * in slow memory node to fast memory node.
  1460		 */
  1461		if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
> 1462		    next_promotion_node(src_nid) != -1) {
  1463			struct pglist_data *pgdat;
  1464			unsigned long rate_limit;
  1465	
  1466			pgdat = NODE_DATA(dst_nid);
  1467			if (pgdat_free_space_enough(pgdat))
  1468				return true;
  1469	
  1470			rate_limit =
  1471				sysctl_numa_balancing_rate_limit << (20 - PAGE_SHIFT);
  1472			return numa_migration_check_rate_limit(pgdat, rate_limit,
  1473							       hpage_nr_pages(page));
  1474		}
  1475	
  1476		this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid);
  1477		last_cpupid = page_cpupid_xchg_last(page, this_cpupid);
  1478	
  1479		/*
  1480		 * Allow first faults or private faults to migrate immediately early in
  1481		 * the lifetime of a task. The magic number 4 is based on waiting for
  1482		 * two full passes of the "multi-stage node selection" test that is
  1483		 * executed below.
  1484		 */
  1485		if ((p->numa_preferred_nid == NUMA_NO_NODE || p->numa_scan_seq <= 4) &&
  1486		    (cpupid_pid_unset(last_cpupid) || cpupid_match_pid(p, last_cpupid)))
  1487			return true;
  1488	
  1489		/*
  1490		 * Multi-stage node selection is used in conjunction with a periodic
  1491		 * migration fault to build a temporal task<->page relation. By using
  1492		 * a two-stage filter we remove short/unlikely relations.
  1493		 *
  1494		 * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate
  1495		 * a task's usage of a particular page (n_p) per total usage of this
  1496		 * page (n_t) (in a given time-span) to a probability.
  1497		 *
  1498		 * Our periodic faults will sample this probability and getting the
  1499		 * same result twice in a row, given these samples are fully
  1500		 * independent, is then given by P(n)^2, provided our sample period
  1501		 * is sufficiently short compared to the usage pattern.
  1502		 *
  1503		 * This quadric squishes small probabilities, making it less likely we
  1504		 * act on an unlikely task<->page relation.
  1505		 */
  1506		if (!cpupid_pid_unset(last_cpupid) &&
  1507					cpupid_to_nid(last_cpupid) != dst_nid)
  1508			return false;
  1509	
  1510		/* Always allow migrate on private faults */
  1511		if (cpupid_match_pid(p, last_cpupid))
  1512			return true;
  1513	
  1514		/* A shared fault, but p->numa_group has not been set up yet. */
  1515		if (!ng)
  1516			return true;
  1517	
  1518		/*
  1519		 * Destination node is much more heavily used than the source
  1520		 * node? Allow migration.
  1521		 */
  1522		if (group_faults_cpu(ng, dst_nid) > group_faults_cpu(ng, src_nid) *
  1523						ACTIVE_NODE_FRACTION)
  1524			return true;
  1525	
  1526		/*
  1527		 * Distribute memory according to CPU & memory use on each node,
  1528		 * with 3/4 hysteresis to avoid unnecessary memory migrations:
  1529		 *
  1530		 * faults_cpu(dst)   3   faults_cpu(src)
  1531		 * --------------- * - > ---------------
  1532		 * faults_mem(dst)   4   faults_mem(src)
  1533		 */
  1534		return group_faults_cpu(ng, dst_nid) * group_faults(p, src_nid) * 3 >
  1535		       group_faults_cpu(ng, src_nid) * group_faults(p, dst_nid) * 4;
  1536	}
  1537	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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