Subject: mm, numa: Do not group on RO pages From: Peter Zijlstra <pet...@infradead.org> Date: Fri Aug 2 18:38:34 CEST 2013
And here's a little something to make sure not the whole world ends up in a single group. As while we don't migrate shared executable pages, we do scan/fault on them. And since everybody links to libc, everybody ends up in the same group. Sugested-by: Rik van Riel <r...@redhat.com> Signed-off-by: Peter Zijlstra <pet...@infradead.org> --- include/linux/sched.h | 7 +++++-- kernel/sched/fair.c | 5 +++-- mm/huge_memory.c | 15 +++++++++++++-- mm/memory.c | 31 ++++++++++++++++++++++++++----- 4 files changed, 47 insertions(+), 11 deletions(-) --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1438,12 +1438,15 @@ struct task_struct { /* Future-safe accessor for struct task_struct's cpus_allowed. */ #define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed) +#define TNF_MIGRATED 0x01 +#define TNF_NO_GROUP 0x02 + #ifdef CONFIG_NUMA_BALANCING -extern void task_numa_fault(int last_node, int node, int pages, bool migrated); +extern void task_numa_fault(int last_node, int node, int pages, int flags); extern void set_numabalancing_state(bool enabled); #else static inline void task_numa_fault(int last_node, int node, int pages, - bool migrated) + int flags) { } static inline void set_numabalancing_state(bool enabled) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1371,9 +1371,10 @@ void task_numa_free(struct task_struct * /* * Got a PROT_NONE fault for a page on @node. */ -void task_numa_fault(int last_cpupid, int node, int pages, bool migrated) +void task_numa_fault(int last_cpupid, int node, int pages, int flags) { struct task_struct *p = current; + bool migrated = flags & TNF_MIGRATED; int priv; if (!numabalancing_enabled) @@ -1409,7 +1410,7 @@ void task_numa_fault(int last_cpupid, in pid = cpupid_to_pid(last_cpupid); priv = (pid == (p->pid & LAST__PID_MASK)); - if (!priv) + if (!priv && !(flags & TNF_NO_GROUP)) task_numa_group(p, cpu, pid); } --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1295,6 +1295,7 @@ int do_huge_pmd_numa_page(struct mm_stru int page_nid = -1, account_nid = -1, this_nid = numa_node_id(); int target_nid, last_cpupid; bool migrated = false; + int flags = 0; spin_lock(&mm->page_table_lock); if (unlikely(!pmd_same(pmd, *pmdp))) @@ -1333,6 +1334,15 @@ int do_huge_pmd_numa_page(struct mm_stru account_nid = page_nid = -1; /* someone else took our fault */ goto out_unlock; } + + /* + * Avoid grouping on DSO/COW pages in specific and RO pages + * in general, RO pages shouldn't hurt as much anyway since + * they can be in shared cache state. + */ + if (page_mapcount(page) != 1 && !pmd_write(pmd)) + flags |= TNF_NO_GROUP; + spin_unlock(&mm->page_table_lock); /* Migrate the THP to the requested node */ @@ -1341,7 +1351,8 @@ int do_huge_pmd_numa_page(struct mm_stru if (!migrated) { account_nid = -1; /* account against the old page */ goto check_same; - } + } else + flags |= TNF_MIGRATED; page_nid = target_nid; goto out; @@ -1364,7 +1375,7 @@ int do_huge_pmd_numa_page(struct mm_stru if (account_nid == -1) account_nid = page_nid; if (account_nid != -1) - task_numa_fault(last_cpupid, account_nid, HPAGE_PMD_NR, migrated); + task_numa_fault(last_cpupid, account_nid, HPAGE_PMD_NR, flags); return 0; } --- a/mm/memory.c +++ b/mm/memory.c @@ -3537,6 +3537,7 @@ int do_numa_page(struct mm_struct *mm, s int page_nid = -1, account_nid = -1; int target_nid, last_cpupid; bool migrated = false; + int flags = 0; /* * The "pte" at this point cannot be used safely without @@ -3569,6 +3570,14 @@ int do_numa_page(struct mm_struct *mm, s return 0; } + /* + * Avoid grouping on DSO/COW pages in specific and RO pages + * in general, RO pages shouldn't hurt as much anyway since + * they can be in shared cache state. + */ + if (page_mapcount(page) != 1 && !pte_write(pte)) + flags |= TNF_NO_GROUP; + last_cpupid = page_cpupid_last(page); page_nid = page_to_nid(page); target_nid = numa_migrate_prep(page, vma, addr, page_nid, &account_nid); @@ -3580,14 +3589,16 @@ int do_numa_page(struct mm_struct *mm, s /* Migrate to the requested node */ migrated = migrate_misplaced_page(page, vma, target_nid); - if (migrated) + if (migrated) { page_nid = target_nid; + flags |= TNF_MIGRATED; + } out: if (account_nid == -1) account_nid = page_nid; if (account_nid != -1) - task_numa_fault(last_cpupid, account_nid, 1, migrated); + task_numa_fault(last_cpupid, account_nid, 1, flags); return 0; } @@ -3632,6 +3643,7 @@ static int do_pmd_numa_page(struct mm_st int page_nid = -1, account_nid = -1; int target_nid; bool migrated = false; + int flags = 0; if (!pte_present(pteval)) continue; @@ -3651,6 +3663,14 @@ static int do_pmd_numa_page(struct mm_st if (unlikely(!page)) continue; + /* + * Avoid grouping on DSO/COW pages in specific and RO pages + * in general, RO pages shouldn't hurt as much anyway since + * they can be in shared cache state. + */ + if (page_mapcount(page) != 1 && !pte_write(pteval)) + flags |= TNF_NO_GROUP; + last_cpupid = page_cpupid_last(page); page_nid = page_to_nid(page); target_nid = numa_migrate_prep(page, vma, addr, @@ -3659,9 +3679,10 @@ static int do_pmd_numa_page(struct mm_st if (target_nid != -1) { migrated = migrate_misplaced_page(page, vma, target_nid); - if (migrated) + if (migrated) { page_nid = target_nid; - else + flags |= TNF_MIGRATED; + } else account_nid = -1; } else { put_page(page); @@ -3670,7 +3691,7 @@ static int do_pmd_numa_page(struct mm_st if (account_nid == -1) account_nid = page_nid; if (account_nid != -1) - task_numa_fault(last_cpupid, account_nid, 1, migrated); + task_numa_fault(last_cpupid, account_nid, 1, flags); cond_resched(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/