From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Subject: mm: consolidate page table accounting Currently, we account page tables separately for each page table level, but that's redundant -- we only make use of total memory allocated to page tables for oom_badness calculation. We also provide the information to userspace, but it has dubious value there too. This patch switches page table accounting to single counter. mm->pgtables_bytes is now used to account all page table levels. We use bytes, because page table size for different levels of page table tree may be different. The change has user-visible effect: we don't have VmPMD and VmPUD reported in /proc/[pid]/status. Not sure if anybody uses them. (As alternative, we can always report 0 kB for them.) OOM-killer report is also slightly changed: we now report pgtables_bytes instead of nr_ptes, nr_pmd, nr_puds. Apart from reducing number of counters per-mm, the benefit is that we now calculate oom_badness() more correctly for machines which have different size of page tables depending on level or where page tables are less than a page in size. The only downside can be debuggability because we do not know which page table level could leak. But I do not remember many bugs that would be caught by separate counters so I wouldn't lose sleep over this. [akpm@xxxxxxxxxxxxxxxxxxxx: fix mm/huge_memory.c] Link: http://lkml.kernel.org/r/20171006100651.44742-2-kirill.shutemov@xxxxxxxxxxxxxxx Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> [kirill.shutemov@xxxxxxxxxxxxxxx: fix build] Link: http://lkml.kernel.org/r/20171016150113.ikfxy3e7zzfvsr4w@xxxxxxxxxxxxxxxxxx Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/filesystems/proc.txt | 1 Documentation/sysctl/vm.txt | 8 +-- fs/proc/task_mmu.c | 11 ----- include/linux/mm.h | 58 +++++---------------------- include/linux/mm_types.h | 8 --- kernel/fork.c | 16 +------ mm/debug.c | 7 --- mm/huge_memory.c | 2 mm/oom_kill.c | 14 ++---- 9 files changed, 32 insertions(+), 93 deletions(-) diff -puN Documentation/filesystems/proc.txt~mm-consolidate-page-table-accounting Documentation/filesystems/proc.txt --- a/Documentation/filesystems/proc.txt~mm-consolidate-page-table-accounting +++ a/Documentation/filesystems/proc.txt @@ -250,7 +250,6 @@ Table 1-2: Contents of the status files VmExe size of text segment VmLib size of shared library code VmPTE size of page table entries - VmPMD size of second level page tables VmSwap amount of swap used by anonymous private data (shmem swap usage is not included) HugetlbPages size of hugetlb memory portions diff -puN Documentation/sysctl/vm.txt~mm-consolidate-page-table-accounting Documentation/sysctl/vm.txt --- a/Documentation/sysctl/vm.txt~mm-consolidate-page-table-accounting +++ a/Documentation/sysctl/vm.txt @@ -629,10 +629,10 @@ oom_dump_tasks Enables a system-wide task dump (excluding kernel threads) to be produced when the kernel performs an OOM-killing and includes such information as -pid, uid, tgid, vm size, rss, nr_ptes, nr_pmds, nr_puds, swapents, -oom_score_adj score, and name. This is helpful to determine why the OOM -killer was invoked, to identify the rogue task that caused it, and to -determine why the OOM killer chose the task it did to kill. +pid, uid, tgid, vm size, rss, pgtables_bytes, swapents, oom_score_adj +score, and name. This is helpful to determine why the OOM killer was +invoked, to identify the rogue task that caused it, and to determine why +the OOM killer chose the task it did to kill. If this is set to zero, this information is suppressed. On very large systems with thousands of tasks it may not be feasible to dump diff -puN fs/proc/task_mmu.c~mm-consolidate-page-table-accounting fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c~mm-consolidate-page-table-accounting +++ a/fs/proc/task_mmu.c @@ -26,7 +26,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) { - unsigned long text, lib, swap, ptes, pmds, puds, anon, file, shmem; + unsigned long text, lib, swap, anon, file, shmem; unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss; anon = get_mm_counter(mm, MM_ANONPAGES); @@ -50,9 +50,6 @@ void task_mem(struct seq_file *m, struct text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10; lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text; swap = get_mm_counter(mm, MM_SWAPENTS); - ptes = PTRS_PER_PTE * sizeof(pte_t) * mm_nr_ptes(mm); - pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm); - puds = PTRS_PER_PUD * sizeof(pud_t) * mm_nr_puds(mm); seq_printf(m, "VmPeak:\t%8lu kB\n" "VmSize:\t%8lu kB\n" @@ -68,8 +65,6 @@ void task_mem(struct seq_file *m, struct "VmExe:\t%8lu kB\n" "VmLib:\t%8lu kB\n" "VmPTE:\t%8lu kB\n" - "VmPMD:\t%8lu kB\n" - "VmPUD:\t%8lu kB\n" "VmSwap:\t%8lu kB\n", hiwater_vm << (PAGE_SHIFT-10), total_vm << (PAGE_SHIFT-10), @@ -82,9 +77,7 @@ void task_mem(struct seq_file *m, struct shmem << (PAGE_SHIFT-10), mm->data_vm << (PAGE_SHIFT-10), mm->stack_vm << (PAGE_SHIFT-10), text, lib, - ptes >> 10, - pmds >> 10, - puds >> 10, + mm_pgtables_bytes(mm) >> 10, swap << (PAGE_SHIFT-10)); hugetlb_report_usage(m, mm); } diff -puN include/linux/mm.h~mm-consolidate-page-table-accounting include/linux/mm.h --- a/include/linux/mm.h~mm-consolidate-page-table-accounting +++ a/include/linux/mm.h @@ -1605,37 +1605,20 @@ static inline int __pud_alloc(struct mm_ { return 0; } - -static inline unsigned long mm_nr_puds(const struct mm_struct *mm) -{ - return 0; -} - -static inline void mm_nr_puds_init(struct mm_struct *mm) {} static inline void mm_inc_nr_puds(struct mm_struct *mm) {} static inline void mm_dec_nr_puds(struct mm_struct *mm) {} #else int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address); -static inline void mm_nr_puds_init(struct mm_struct *mm) -{ - atomic_long_set(&mm->nr_puds, 0); -} - -static inline unsigned long mm_nr_puds(const struct mm_struct *mm) -{ - return atomic_long_read(&mm->nr_puds); -} - static inline void mm_inc_nr_puds(struct mm_struct *mm) { - atomic_long_inc(&mm->nr_puds); + atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes); } static inline void mm_dec_nr_puds(struct mm_struct *mm) { - atomic_long_dec(&mm->nr_puds); + atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes); } #endif @@ -1646,64 +1629,47 @@ static inline int __pmd_alloc(struct mm_ return 0; } -static inline void mm_nr_pmds_init(struct mm_struct *mm) {} - -static inline unsigned long mm_nr_pmds(const struct mm_struct *mm) -{ - return 0; -} - static inline void mm_inc_nr_pmds(struct mm_struct *mm) {} static inline void mm_dec_nr_pmds(struct mm_struct *mm) {} #else int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address); -static inline void mm_nr_pmds_init(struct mm_struct *mm) -{ - atomic_long_set(&mm->nr_pmds, 0); -} - -static inline unsigned long mm_nr_pmds(const struct mm_struct *mm) -{ - return atomic_long_read(&mm->nr_pmds); -} - static inline void mm_inc_nr_pmds(struct mm_struct *mm) { - atomic_long_inc(&mm->nr_pmds); + atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes); } static inline void mm_dec_nr_pmds(struct mm_struct *mm) { - atomic_long_dec(&mm->nr_pmds); + atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes); } #endif #ifdef CONFIG_MMU -static inline void mm_nr_ptes_init(struct mm_struct *mm) +static inline void mm_pgtables_bytes_init(struct mm_struct *mm) { - atomic_long_set(&mm->nr_ptes, 0); + atomic_long_set(&mm->pgtables_bytes, 0); } -static inline unsigned long mm_nr_ptes(const struct mm_struct *mm) +static inline unsigned long mm_pgtables_bytes(const struct mm_struct *mm) { - return atomic_long_read(&mm->nr_ptes); + return atomic_long_read(&mm->pgtables_bytes); } static inline void mm_inc_nr_ptes(struct mm_struct *mm) { - atomic_long_inc(&mm->nr_ptes); + atomic_long_add(PTRS_PER_PTE * sizeof(pte_t), &mm->pgtables_bytes); } static inline void mm_dec_nr_ptes(struct mm_struct *mm) { - atomic_long_dec(&mm->nr_ptes); + atomic_long_sub(PTRS_PER_PTE * sizeof(pte_t), &mm->pgtables_bytes); } #else -static inline void mm_nr_ptes_init(struct mm_struct *mm) {} -static inline unsigned long mm_nr_ptes(const struct mm_struct *mm) +static inline void mm_pgtables_bytes_init(struct mm_struct *mm) {} +static inline unsigned long mm_pgtables_bytes(const struct mm_struct *mm) { return 0; } diff -puN include/linux/mm_types.h~mm-consolidate-page-table-accounting include/linux/mm_types.h --- a/include/linux/mm_types.h~mm-consolidate-page-table-accounting +++ a/include/linux/mm_types.h @@ -402,13 +402,7 @@ struct mm_struct { atomic_t mm_count; #ifdef CONFIG_MMU - atomic_long_t nr_ptes; /* PTE page table pages */ -#endif -#if CONFIG_PGTABLE_LEVELS > 2 - atomic_long_t nr_pmds; /* PMD page table pages */ -#endif -#if CONFIG_PGTABLE_LEVELS > 3 - atomic_long_t nr_puds; /* PUD page table pages */ + atomic_long_t pgtables_bytes; /* PTE page table pages */ #endif int map_count; /* number of VMAs */ diff -puN kernel/fork.c~mm-consolidate-page-table-accounting kernel/fork.c --- a/kernel/fork.c~mm-consolidate-page-table-accounting +++ a/kernel/fork.c @@ -817,9 +817,7 @@ static struct mm_struct *mm_init(struct init_rwsem(&mm->mmap_sem); INIT_LIST_HEAD(&mm->mmlist); mm->core_state = NULL; - mm_nr_ptes_init(mm); - mm_nr_pmds_init(mm); - mm_nr_puds_init(mm); + mm_pgtables_bytes_init(mm); mm->map_count = 0; mm->locked_vm = 0; mm->pinned_vm = 0; @@ -873,15 +871,9 @@ static void check_mm(struct mm_struct *m "mm:%p idx:%d val:%ld\n", mm, i, x); } - if (mm_nr_ptes(mm)) - pr_alert("BUG: non-zero nr_ptes on freeing mm: %ld\n", - mm_nr_ptes(mm)); - if (mm_nr_pmds(mm)) - pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld\n", - mm_nr_pmds(mm)); - if (mm_nr_puds(mm)) - pr_alert("BUG: non-zero nr_puds on freeing mm: %ld\n", - mm_nr_puds(mm)); + if (mm_pgtables_bytes(mm)) + pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n", + mm_pgtables_bytes(mm)); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS VM_BUG_ON_MM(mm->pmd_huge_pte, mm); diff -puN mm/debug.c~mm-consolidate-page-table-accounting mm/debug.c --- a/mm/debug.c~mm-consolidate-page-table-accounting +++ a/mm/debug.c @@ -105,8 +105,7 @@ void dump_mm(const struct mm_struct *mm) "get_unmapped_area %p\n" #endif "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n" - "pgd %p mm_users %d mm_count %d\n" - "nr_ptes %lu nr_pmds %lu nr_puds %lu map_count %d\n" + "pgd %p mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n" "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" "pinned_vm %lx data_vm %lx exec_vm %lx stack_vm %lx\n" "start_code %lx end_code %lx start_data %lx end_data %lx\n" @@ -136,9 +135,7 @@ void dump_mm(const struct mm_struct *mm) mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end, mm->pgd, atomic_read(&mm->mm_users), atomic_read(&mm->mm_count), - mm_nr_ptes(mm), - mm_nr_pmds(mm), - mm_nr_puds(mm), + mm_pgtables_bytes(mm), mm->map_count, mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm, diff -puN mm/huge_memory.c~mm-consolidate-page-table-accounting mm/huge_memory.c --- a/mm/huge_memory.c~mm-consolidate-page-table-accounting +++ a/mm/huge_memory.c @@ -942,7 +942,7 @@ int copy_huge_pmd(struct mm_struct *dst_ set_pmd_at(src_mm, addr, src_pmd, pmd); } add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); - atomic_long_inc(&dst_mm->nr_ptes); + mm_inc_nr_ptes(dst_mm); pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); set_pmd_at(dst_mm, addr, dst_pmd, pmd); ret = 0; diff -puN mm/oom_kill.c~mm-consolidate-page-table-accounting mm/oom_kill.c --- a/mm/oom_kill.c~mm-consolidate-page-table-accounting +++ a/mm/oom_kill.c @@ -221,7 +221,7 @@ unsigned long oom_badness(struct task_st * task's rss, pagetable and swap space use. */ points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) + - mm_nr_ptes(p->mm) + mm_nr_pmds(p->mm) + mm_nr_puds(p->mm); + mm_pgtables_bytes(p->mm) / PAGE_SIZE; task_unlock(p); /* @@ -389,15 +389,15 @@ static void select_bad_process(struct oo * Dumps the current memory state of all eligible tasks. Tasks not in the same * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes * are not shown. - * State information includes task's pid, uid, tgid, vm size, rss, nr_ptes, - * swapents, oom_score_adj value, and name. + * State information includes task's pid, uid, tgid, vm size, rss, + * pgtables_bytes, swapents, oom_score_adj value, and name. */ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask) { struct task_struct *p; struct task_struct *task; - pr_info("[ pid ] uid tgid total_vm rss nr_ptes nr_pmds nr_puds swapents oom_score_adj name\n"); + pr_info("[ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name\n"); rcu_read_lock(); for_each_process(p) { if (oom_unkillable_task(p, memcg, nodemask)) @@ -413,12 +413,10 @@ static void dump_tasks(struct mem_cgroup continue; } - pr_info("[%5d] %5d %5d %8lu %8lu %7ld %7ld %7ld %8lu %5hd %s\n", + pr_info("[%5d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n", task->pid, from_kuid(&init_user_ns, task_uid(task)), task->tgid, task->mm->total_vm, get_mm_rss(task->mm), - mm_nr_ptes(task->mm), - mm_nr_pmds(task->mm), - mm_nr_puds(task->mm), + mm_pgtables_bytes(task->mm), get_mm_counter(task->mm, MM_SWAPENTS), task->signal->oom_score_adj, task->comm); task_unlock(task); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
