The patch titled Subject: mm: account pmd page tables to the process has been removed from the -mm tree. Its filename was mm-account-pmd-page-tables-to-the-process.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Subject: mm: account pmd page tables to the process Dave noticed that unprivileged process can allocate significant amount of memory -- >500 MiB on x86_64 -- and stay unnoticed by oom-killer and memory cgroup. The trick is to allocate a lot of PMD page tables. Linux kernel doesn't account PMD tables to the process, only PTE. The use-cases below use few tricks to allocate a lot of PMD page tables while keeping VmRSS and VmPTE low. oom_score for the process will be 0. #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/mman.h> #include <sys/prctl.h> #define PUD_SIZE (1UL << 30) #define PMD_SIZE (1UL << 21) #define NR_PUD 130000 int main(void) { char *addr = NULL; unsigned long i; prctl(PR_SET_THP_DISABLE); for (i = 0; i < NR_PUD ; i++) { addr = mmap(addr + PUD_SIZE, PUD_SIZE, PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); if (addr == MAP_FAILED) { perror("mmap"); break; } *addr = 'x'; munmap(addr, PMD_SIZE); mmap(addr, PMD_SIZE, PROT_WRITE|PROT_READ, MAP_ANONYMOUS|MAP_PRIVATE|MAP_FIXED, -1, 0); if (addr == MAP_FAILED) perror("re-mmap"), exit(1); } printf("PID %d consumed %lu KiB in PMD page tables\n", getpid(), i * 4096 >> 10); return pause(); } The patch addresses the issue by account PMD tables to the process the same way we account PTE. The main place where PMD tables is accounted is __pmd_alloc() and free_pmd_range(). But there're few corner cases: - HugeTLB can share PMD page tables. The patch handles by accounting the table to all processes who share it. - x86 PAE pre-allocates few PMD tables on fork. - Architectures with FIRST_USER_ADDRESS > 0. We need to adjust sanity check on exit(2). Accounting only happens on configuration where PMD page table's level is present (PMD is not folded). As with nr_ptes we use per-mm counter. The counter value is used to calculate baseline for badness score by oom-killer. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reported-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Reviewed-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/sysctl/vm.txt | 12 ++++++------ arch/x86/mm/pgtable.c | 14 +++++++++----- fs/proc/task_mmu.c | 9 ++++++--- include/linux/mm.h | 24 ++++++++++++++++++++++++ include/linux/mm_types.h | 3 ++- kernel/fork.c | 3 +++ mm/debug.c | 3 ++- mm/hugetlb.c | 8 ++++++-- mm/memory.c | 15 +++++++++------ mm/mmap.c | 4 +++- mm/oom_kill.c | 9 +++++---- 11 files changed, 75 insertions(+), 29 deletions(-) diff -puN Documentation/sysctl/vm.txt~mm-account-pmd-page-tables-to-the-process Documentation/sysctl/vm.txt --- a/Documentation/sysctl/vm.txt~mm-account-pmd-page-tables-to-the-process +++ a/Documentation/sysctl/vm.txt @@ -555,12 +555,12 @@ this is causing problems for your system 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, 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. +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, 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 arch/x86/mm/pgtable.c~mm-account-pmd-page-tables-to-the-process arch/x86/mm/pgtable.c --- a/arch/x86/mm/pgtable.c~mm-account-pmd-page-tables-to-the-process +++ a/arch/x86/mm/pgtable.c @@ -190,7 +190,7 @@ void pud_populate(struct mm_struct *mm, #endif /* CONFIG_X86_PAE */ -static void free_pmds(pmd_t *pmds[]) +static void free_pmds(struct mm_struct *mm, pmd_t *pmds[]) { int i; @@ -198,10 +198,11 @@ static void free_pmds(pmd_t *pmds[]) if (pmds[i]) { pgtable_pmd_page_dtor(virt_to_page(pmds[i])); free_page((unsigned long)pmds[i]); + mm_dec_nr_pmds(mm); } } -static int preallocate_pmds(pmd_t *pmds[]) +static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[]) { int i; bool failed = false; @@ -215,11 +216,13 @@ static int preallocate_pmds(pmd_t *pmds[ pmd = NULL; failed = true; } + if (pmd) + mm_inc_nr_pmds(mm); pmds[i] = pmd; } if (failed) { - free_pmds(pmds); + free_pmds(mm, pmds); return -ENOMEM; } @@ -246,6 +249,7 @@ static void pgd_mop_up_pmds(struct mm_st paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT); pmd_free(mm, pmd); + mm_dec_nr_pmds(mm); } } } @@ -283,7 +287,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm) mm->pgd = pgd; - if (preallocate_pmds(pmds) != 0) + if (preallocate_pmds(mm, pmds) != 0) goto out_free_pgd; if (paravirt_pgd_alloc(mm) != 0) @@ -304,7 +308,7 @@ pgd_t *pgd_alloc(struct mm_struct *mm) return pgd; out_free_pmds: - free_pmds(pmds); + free_pmds(mm, pmds); out_free_pgd: free_page((unsigned long)pgd); out: diff -puN fs/proc/task_mmu.c~mm-account-pmd-page-tables-to-the-process fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c~mm-account-pmd-page-tables-to-the-process +++ a/fs/proc/task_mmu.c @@ -21,7 +21,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) { - unsigned long data, text, lib, swap; + unsigned long data, text, lib, swap, ptes, pmds; unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss; /* @@ -42,6 +42,8 @@ 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) * atomic_long_read(&mm->nr_ptes); + pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm); seq_printf(m, "VmPeak:\t%8lu kB\n" "VmSize:\t%8lu kB\n" @@ -54,6 +56,7 @@ 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" "VmSwap:\t%8lu kB\n", hiwater_vm << (PAGE_SHIFT-10), total_vm << (PAGE_SHIFT-10), @@ -63,8 +66,8 @@ void task_mem(struct seq_file *m, struct total_rss << (PAGE_SHIFT-10), data << (PAGE_SHIFT-10), mm->stack_vm << (PAGE_SHIFT-10), text, lib, - (PTRS_PER_PTE * sizeof(pte_t) * - atomic_long_read(&mm->nr_ptes)) >> 10, + ptes >> 10, + pmds >> 10, swap << (PAGE_SHIFT-10)); } diff -puN include/linux/mm.h~mm-account-pmd-page-tables-to-the-process include/linux/mm.h --- a/include/linux/mm.h~mm-account-pmd-page-tables-to-the-process +++ a/include/linux/mm.h @@ -1438,8 +1438,32 @@ static inline int __pmd_alloc(struct mm_ { return 0; } + +static inline unsigned long mm_nr_pmds(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 unsigned long mm_nr_pmds(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); +} + +static inline void mm_dec_nr_pmds(struct mm_struct *mm) +{ + atomic_long_dec(&mm->nr_pmds); +} #endif int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, diff -puN include/linux/mm_types.h~mm-account-pmd-page-tables-to-the-process include/linux/mm_types.h --- a/include/linux/mm_types.h~mm-account-pmd-page-tables-to-the-process +++ a/include/linux/mm_types.h @@ -363,7 +363,8 @@ struct mm_struct { pgd_t * pgd; atomic_t mm_users; /* How many users with user space? */ atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */ - atomic_long_t nr_ptes; /* Page table pages */ + atomic_long_t nr_ptes; /* PTE page table pages */ + atomic_long_t nr_pmds; /* PMD page table pages */ int map_count; /* number of VMAs */ spinlock_t page_table_lock; /* Protects page tables and some counters */ diff -puN kernel/fork.c~mm-account-pmd-page-tables-to-the-process kernel/fork.c --- a/kernel/fork.c~mm-account-pmd-page-tables-to-the-process +++ a/kernel/fork.c @@ -555,6 +555,9 @@ static struct mm_struct *mm_init(struct INIT_LIST_HEAD(&mm->mmlist); mm->core_state = NULL; atomic_long_set(&mm->nr_ptes, 0); +#ifndef __PAGETABLE_PMD_FOLDED + atomic_long_set(&mm->nr_pmds, 0); +#endif mm->map_count = 0; mm->locked_vm = 0; mm->pinned_vm = 0; diff -puN mm/debug.c~mm-account-pmd-page-tables-to-the-process mm/debug.c --- a/mm/debug.c~mm-account-pmd-page-tables-to-the-process +++ a/mm/debug.c @@ -173,7 +173,7 @@ 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 nr_ptes %lu map_count %d\n" + "pgd %p mm_users %d mm_count %d nr_ptes %lu nr_pmds %lu map_count %d\n" "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" "pinned_vm %lx shared_vm %lx exec_vm %lx stack_vm %lx\n" "start_code %lx end_code %lx start_data %lx end_data %lx\n" @@ -206,6 +206,7 @@ void dump_mm(const struct mm_struct *mm) mm->pgd, atomic_read(&mm->mm_users), atomic_read(&mm->mm_count), atomic_long_read((atomic_long_t *)&mm->nr_ptes), + mm_nr_pmds((struct mm_struct *)mm), mm->map_count, mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, mm->pinned_vm, mm->shared_vm, mm->exec_vm, mm->stack_vm, diff -puN mm/hugetlb.c~mm-account-pmd-page-tables-to-the-process mm/hugetlb.c --- a/mm/hugetlb.c~mm-account-pmd-page-tables-to-the-process +++ a/mm/hugetlb.c @@ -3598,6 +3598,7 @@ pte_t *huge_pmd_share(struct mm_struct * if (saddr) { spte = huge_pte_offset(svma->vm_mm, saddr); if (spte) { + mm_inc_nr_pmds(mm); get_page(virt_to_page(spte)); break; } @@ -3609,11 +3610,13 @@ pte_t *huge_pmd_share(struct mm_struct * ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); spin_lock(ptl); - if (pud_none(*pud)) + if (pud_none(*pud)) { pud_populate(mm, pud, (pmd_t *)((unsigned long)spte & PAGE_MASK)); - else + } else { put_page(virt_to_page(spte)); + mm_inc_nr_pmds(mm); + } spin_unlock(ptl); out: pte = (pte_t *)pmd_alloc(mm, pud, addr); @@ -3644,6 +3647,7 @@ int huge_pmd_unshare(struct mm_struct *m pud_clear(pud); put_page(virt_to_page(ptep)); + mm_dec_nr_pmds(mm); *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; return 1; } diff -puN mm/memory.c~mm-account-pmd-page-tables-to-the-process mm/memory.c --- a/mm/memory.c~mm-account-pmd-page-tables-to-the-process +++ a/mm/memory.c @@ -428,6 +428,7 @@ static inline void free_pmd_range(struct pmd = pmd_offset(pud, start); pud_clear(pud); pmd_free_tlb(tlb, pmd, start); + mm_dec_nr_pmds(tlb->mm); } static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, @@ -3322,15 +3323,17 @@ int __pmd_alloc(struct mm_struct *mm, pu spin_lock(&mm->page_table_lock); #ifndef __ARCH_HAS_4LEVEL_HACK - if (pud_present(*pud)) /* Another has populated it */ - pmd_free(mm, new); - else + if (!pud_present(*pud)) { + mm_inc_nr_pmds(mm); pud_populate(mm, pud, new); -#else - if (pgd_present(*pud)) /* Another has populated it */ + } else /* Another has populated it */ pmd_free(mm, new); - else +#else + if (!pgd_present(*pud)) { + mm_inc_nr_pmds(mm); pgd_populate(mm, pud, new); + } else /* Another has populated it */ + pmd_free(mm, new); #endif /* __ARCH_HAS_4LEVEL_HACK */ spin_unlock(&mm->page_table_lock); return 0; diff -puN mm/mmap.c~mm-account-pmd-page-tables-to-the-process mm/mmap.c --- a/mm/mmap.c~mm-account-pmd-page-tables-to-the-process +++ a/mm/mmap.c @@ -2853,7 +2853,9 @@ void exit_mmap(struct mm_struct *mm) vm_unacct_memory(nr_accounted); WARN_ON(atomic_long_read(&mm->nr_ptes) > - (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); + round_up(FIRST_USER_ADDRESS, PMD_SIZE) >> PMD_SHIFT); + WARN_ON(mm_nr_pmds(mm) > + round_up(FIRST_USER_ADDRESS, PUD_SIZE) >> PUD_SHIFT); } /* Insert vm structure into process list sorted by address diff -puN mm/oom_kill.c~mm-account-pmd-page-tables-to-the-process mm/oom_kill.c --- a/mm/oom_kill.c~mm-account-pmd-page-tables-to-the-process +++ a/mm/oom_kill.c @@ -169,8 +169,8 @@ unsigned long oom_badness(struct task_st * The baseline for the badness score is the proportion of RAM that each * task's rss, pagetable and swap space use. */ - points = get_mm_rss(p->mm) + atomic_long_read(&p->mm->nr_ptes) + - get_mm_counter(p->mm, MM_SWAPENTS); + points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) + + atomic_long_read(&p->mm->nr_ptes) + mm_nr_pmds(p->mm); task_unlock(p); /* @@ -351,7 +351,7 @@ static void dump_tasks(struct mem_cgroup struct task_struct *p; struct task_struct *task; - pr_info("[ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name\n"); + pr_info("[ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name\n"); rcu_read_lock(); for_each_process(p) { if (oom_unkillable_task(p, memcg, nodemask)) @@ -367,10 +367,11 @@ static void dump_tasks(struct mem_cgroup continue; } - pr_info("[%5d] %5d %5d %8lu %8lu %7ld %8lu %5hd %s\n", + pr_info("[%5d] %5d %5d %8lu %8lu %7ld %7ld %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), atomic_long_read(&task->mm->nr_ptes), + mm_nr_pmds(task->mm), get_mm_counter(task->mm, MM_SWAPENTS), task->signal->oom_score_adj, task->comm); task_unlock(task); _ Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are origin.patch mm-numa-do-not-dereference-pmd-outside-of-the-lock-during-numa-hinting-fault.patch mm-add-p-protnone-helpers-for-use-by-numa-balancing.patch mm-convert-p_numa-users-to-p_protnone_numa.patch ppc64-add-paranoid-warnings-for-unexpected-dsisr_protfault.patch mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch mm-remove-remaining-references-to-numa-hinting-bits-and-helpers.patch mm-numa-do-not-trap-faults-on-the-huge-zero-page.patch x86-mm-restore-original-pte_special-check.patch mm-numa-add-paranoid-check-around-pte_protnone_numa.patch mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.patch mm-do-not-use-mm-nr_pmds-on-mmu-configurations.patch mm-fix-xip-fault-vs-truncate-race.patch mm-fix-xip-fault-vs-truncate-race-fix.patch mm-allow-page-fault-handlers-to-perform-the-cow.patch mm-allow-page-fault-handlers-to-perform-the-cow-fix.patch vfsext2-introduce-is_daxinode.patch daxext2-replace-xip-read-and-write-with-dax-i-o.patch daxext2-replace-ext2_clear_xip_target-with-dax_clear_blocks.patch daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler.patch daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler-fix.patch daxext2-replace-xip_truncate_page-with-dax_truncate_page.patch dax-replace-xip-documentation-with-dax-documentation.patch vfs-remove-get_xip_mem.patch ext2-remove-ext2_xip_verify_sb.patch ext2-remove-ext2_use_xip.patch ext2-remove-xipc-and-xiph.patch vfsext2-remove-config_ext2_fs_xip-and-rename-config_fs_xip-to-config_fs_dax.patch ext2-remove-ext2_aops_xip.patch ext2-get-rid-of-most-mentions-of-xip-in-ext2.patch dax-add-dax_zero_page_range.patch dax-add-dax_zero_page_range-fix.patch ext4-add-dax-functionality.patch brd-rename-xip-to-dax.patch powerpc-drop-_page_file-and-pte_file-related-helpers.patch -- 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