From: Huang Ying <ying.huang@xxxxxxxxx> The write performance of PMEM is much worse than its read performance. So even if a write-mostly pages is colder than a read-mostly pages, it is usually better to put the write-mostly pages in DRAM and read-mostly pages in PMEM. To give write-mostly pages more opportunity to be promoted to DRAM, in this patch, the hot threshold for write hint page fault is doubled (easier to be promoted). Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx --- include/linux/sched/numa_balancing.h | 1 + kernel/sched/fair.c | 2 ++ mm/memory.c | 3 +++ 3 files changed, 6 insertions(+) diff --git a/include/linux/sched/numa_balancing.h b/include/linux/sched/numa_balancing.h index 4899ec000245..518b3d6143ba 100644 --- a/include/linux/sched/numa_balancing.h +++ b/include/linux/sched/numa_balancing.h @@ -15,6 +15,7 @@ #define TNF_FAULT_LOCAL 0x08 #define TNF_MIGRATE_FAIL 0x10 #define TNF_YOUNG 0x20 +#define TNF_WRITE 0x40 #ifdef CONFIG_NUMA_BALANCING extern void task_numa_fault(int last_node, int node, int pages, int flags); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 773f3220efc4..e5f7f4139c82 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1513,6 +1513,8 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, return false; th = msecs_to_jiffies(sysctl_numa_balancing_hot_threshold); + if (flags & TNF_WRITE) + th *= 2; latency = numa_hint_fault_latency(p, addr); if (latency > th) return false; diff --git a/mm/memory.c b/mm/memory.c index 207caa9e61da..595d3cd62f61 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3829,6 +3829,9 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) if (pte_young(old_pte)) flags |= TNF_YOUNG; + if (vmf->flags & FAULT_FLAG_WRITE) + flags |= TNF_WRITE; + page = vm_normal_page(vma, vmf->address, pte); if (!page) goto unmap_out; -- 2.24.1
