6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> [ Upstream commit ed2da8b725b932b1e2b2f4835bb664d47ed03031 ] NUMA balancing skips or scans VMAs for a variety of reasons. In preparation for completing scans of VMAs regardless of PID access, trace the reasons why a VMA was skipped. In a later patch, the tracing will be used to track if a VMA was forcibly scanned. Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20231010083143.19593-4-mgorman@xxxxxxxxxxxxxxxxxxx Stable-dep-of: f22cde4371f3 ("sched/numa: Fix the vma scan starving issue") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/linux/sched/numa_balancing.h | 8 +++++ include/trace/events/sched.h | 50 ++++++++++++++++++++++++++++ kernel/sched/fair.c | 17 +++++++--- 3 files changed, 71 insertions(+), 4 deletions(-) diff --git a/include/linux/sched/numa_balancing.h b/include/linux/sched/numa_balancing.h index 3988762efe15c..c127a1509e2fa 100644 --- a/include/linux/sched/numa_balancing.h +++ b/include/linux/sched/numa_balancing.h @@ -15,6 +15,14 @@ #define TNF_FAULT_LOCAL 0x08 #define TNF_MIGRATE_FAIL 0x10 +enum numa_vmaskip_reason { + NUMAB_SKIP_UNSUITABLE, + NUMAB_SKIP_SHARED_RO, + NUMAB_SKIP_INACCESSIBLE, + NUMAB_SKIP_SCAN_DELAY, + NUMAB_SKIP_PID_INACTIVE, +}; + #ifdef CONFIG_NUMA_BALANCING extern void task_numa_fault(int last_node, int node, int pages, int flags); extern pid_t task_numa_group_id(struct task_struct *p); diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index fbb99a61f714c..b0d0dbf491ea6 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -664,6 +664,56 @@ DEFINE_EVENT(sched_numa_pair_template, sched_swap_numa, TP_ARGS(src_tsk, src_cpu, dst_tsk, dst_cpu) ); +#ifdef CONFIG_NUMA_BALANCING +#define NUMAB_SKIP_REASON \ + EM( NUMAB_SKIP_UNSUITABLE, "unsuitable" ) \ + EM( NUMAB_SKIP_SHARED_RO, "shared_ro" ) \ + EM( NUMAB_SKIP_INACCESSIBLE, "inaccessible" ) \ + EM( NUMAB_SKIP_SCAN_DELAY, "scan_delay" ) \ + EMe(NUMAB_SKIP_PID_INACTIVE, "pid_inactive" ) + +/* Redefine for export. */ +#undef EM +#undef EMe +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define EMe(a, b) TRACE_DEFINE_ENUM(a); + +NUMAB_SKIP_REASON + +/* Redefine for symbolic printing. */ +#undef EM +#undef EMe +#define EM(a, b) { a, b }, +#define EMe(a, b) { a, b } + +TRACE_EVENT(sched_skip_vma_numa, + + TP_PROTO(struct mm_struct *mm, struct vm_area_struct *vma, + enum numa_vmaskip_reason reason), + + TP_ARGS(mm, vma, reason), + + TP_STRUCT__entry( + __field(unsigned long, numa_scan_offset) + __field(unsigned long, vm_start) + __field(unsigned long, vm_end) + __field(enum numa_vmaskip_reason, reason) + ), + + TP_fast_assign( + __entry->numa_scan_offset = mm->numa_scan_offset; + __entry->vm_start = vma->vm_start; + __entry->vm_end = vma->vm_end; + __entry->reason = reason; + ), + + TP_printk("numa_scan_offset=%lX vm_start=%lX vm_end=%lX reason=%s", + __entry->numa_scan_offset, + __entry->vm_start, + __entry->vm_end, + __print_symbolic(__entry->reason, NUMAB_SKIP_REASON)) +); +#endif /* CONFIG_NUMA_BALANCING */ /* * Tracepoint for waking a polling cpu without an IPI. diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index d07fb0a0da808..7c5f6e94b3cdc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3285,6 +3285,7 @@ static void task_numa_work(struct callback_head *work) do { if (!vma_migratable(vma) || !vma_policy_mof(vma) || is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) { + trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_UNSUITABLE); continue; } @@ -3295,15 +3296,19 @@ static void task_numa_work(struct callback_head *work) * as migrating the pages will be of marginal benefit. */ if (!vma->vm_mm || - (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ))) + (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ))) { + trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_SHARED_RO); continue; + } /* * Skip inaccessible VMAs to avoid any confusion between * PROT_NONE and NUMA hinting ptes */ - if (!vma_is_accessible(vma)) + if (!vma_is_accessible(vma)) { + trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_INACCESSIBLE); continue; + } /* Initialise new per-VMA NUMAB state. */ if (!vma->numab_state) { @@ -3325,12 +3330,16 @@ static void task_numa_work(struct callback_head *work) * delay the scan for new VMAs. */ if (mm->numa_scan_seq && time_before(jiffies, - vma->numab_state->next_scan)) + vma->numab_state->next_scan)) { + trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_SCAN_DELAY); continue; + } /* Do not scan the VMA if task has not accessed */ - if (!vma_is_accessed(vma)) + if (!vma_is_accessed(vma)) { + trace_sched_skip_vma_numa(mm, vma, NUMAB_SKIP_PID_INACTIVE); continue; + } /* * RESET access PIDs regularly for old VMAs. Resetting after checking -- 2.43.0
