mm: account pud page tables

On a machine with 5-level paging support a process can allocate
significant amount of memory and stay unnoticed by oom-killer and memory
cgroup.  The trick is to allocate a lot of PUD page tables.  We don't
account PUD page tables, only PMD and PTE.

We already addressed the same issue for PMD page tables, see commit
dc6c9a35b66b ("mm: account pmd page tables to the process").
Introduction of 5-level paging brings the same issue for PUD page
tables.

The patch expands accounting to PUD level.

[kirill.shutemov@linux.intel.com: s/pmd_t/pud_t/]
Link: http://lkml.kernel.org/r/20171004074305.x35eh5u7ybbt5kar@black.fi.intel.com
[heiko.carstens@de.ibm.com: s390/mm: fix pud table accounting]
Link: http://lkml.kernel.org/r/20171103090551.18231-1-heiko.carstens@de.ibm.com
Link: http://lkml.kernel.org/r/20171002080427.3320-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 30fd16b141968dccfc216f55343bbfd6dc21b245..2729e8db94922eac385f9f4556cfecedf5d2e7c7 100644 (file)
--- a/Documentation/sysctl/vm.txt
+++ b/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, 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, 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.
 
 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 --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 1571a498a33fc6a688713f4f275b7b55cedabace..a9b9083c5e4999bc398442ef3f8945040b47fac6 100644 (file)
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -433,6 +433,7 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
        pud = pud_offset(pgd, start);
        pgd_clear(pgd);
        pud_free_tlb(tlb, pud, start);
+       mm_dec_nr_puds(tlb->mm);
 }
 
 /*

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 43607bb12cc2b303e7e9f87d391f053ad0aae2d2..cf4c1cb17dcd35ab9a18197e9dbeed41d1a0b376 100644 (file)
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -44,6 +44,8 @@ static inline int init_new_context(struct task_struct *tsk,
                mm->context.asce_limit = STACK_TOP_MAX;
                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
                                   _ASCE_USER_BITS | _ASCE_TYPE_REGION3;
+               /* pgd_alloc() did not account this pud */
+               mm_inc_nr_puds(mm);
                break;
        case -PAGE_SIZE:
                /* forked 5-level task, set new asce with new_mm->pgd */
@@ -59,7 +61,7 @@ static inline int init_new_context(struct task_struct *tsk,
                /* forked 2-level compat task, set new asce with new mm->pgd */
                mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
                                   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
-               /* pgd_alloc() did not increase mm->nr_pmds */
+               /* pgd_alloc() did not account this pmd */
                mm_inc_nr_pmds(mm);
        }
        crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));

diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index 5078b7f6889039952c3ed3aba206f18f03156cf5..01f63b4ee2b42bf0c2ed705b44195146db94f1e0 100644 (file)
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -472,6 +472,7 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
        pud = pud_offset(pgd, start);
        pgd_clear(pgd);
        pud_free_tlb(tlb, pud, start);
+       mm_dec_nr_puds(tlb->mm);
 }
 
 void hugetlb_free_pgd_range(struct mmu_gather *tlb,

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6744bd706ecf018f0db0a3e335449945b523ea74..a05ce6186f996571723ddbaad396cb2a1715938c 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/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, anon, file, shmem;
+       unsigned long text, lib, swap, ptes, pmds, puds, anon, file, shmem;
        unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
 
        anon = get_mm_counter(mm, MM_ANONPAGES);
@@ -52,6 +52,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
        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);
+       puds = PTRS_PER_PUD * sizeof(pud_t) * mm_nr_puds(mm);
        seq_printf(m,
                "VmPeak:\t%8lu kB\n"
                "VmSize:\t%8lu kB\n"
@@ -68,6 +69,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                "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),
@@ -82,6 +84,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                mm->stack_vm << (PAGE_SHIFT-10), text, lib,
                ptes >> 10,
                pmds >> 10,
+               puds >> 10,
                swap << (PAGE_SHIFT-10));
        hugetlb_report_usage(m, mm);
 }

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 91b46f99b4d2189291ddc47ba47690ba79db6251..9af86f39d9284d1e78aa2d56be477d9a9809847f 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1599,14 +1599,44 @@ static inline int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd,
 int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
 #endif
 
-#ifdef __PAGETABLE_PUD_FOLDED
+#if defined(__PAGETABLE_PUD_FOLDED) || !defined(CONFIG_MMU)
 static inline int __pud_alloc(struct mm_struct *mm, p4d_t *p4d,
                                                unsigned long address)
 {
        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);
+}
+
+static inline void mm_dec_nr_puds(struct mm_struct *mm)
+{
+       atomic_long_dec(&mm->nr_puds);
+}
 #endif
 
 #if defined(__PAGETABLE_PMD_FOLDED) || !defined(CONFIG_MMU)
@@ -1618,7 +1648,7 @@ static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
 
 static inline void mm_nr_pmds_init(struct mm_struct *mm) {}
 
-static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
+static inline unsigned long mm_nr_pmds(const struct mm_struct *mm)
 {
        return 0;
 }
@@ -1634,7 +1664,7 @@ 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(struct mm_struct *mm)
+static inline unsigned long mm_nr_pmds(const struct mm_struct *mm)
 {
        return atomic_long_read(&mm->nr_pmds);
 }

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d1b8e8f97fc2cf563c8396014e68da30c2b603c4..e9e561e02d229fa69a7428bc739b770a2552efa4 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -404,6 +404,9 @@ struct mm_struct {
        atomic_long_t nr_ptes;                  /* PTE page table pages */
 #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 */
 #endif
        int map_count;                          /* number of VMAs */
 

diff --git a/kernel/fork.c b/kernel/fork.c
index 07cc743698d3668ef7fb4442c6de0e12de7f02f5..a4eb6f2893657a0e41dd92742cb8fdf0c1839acb 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -819,6 +819,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
        mm->core_state = NULL;
        atomic_long_set(&mm->nr_ptes, 0);
        mm_nr_pmds_init(mm);
+       mm_nr_puds_init(mm);
        mm->map_count = 0;
        mm->locked_vm = 0;
        mm->pinned_vm = 0;
@@ -878,6 +879,9 @@ static void check_mm(struct mm_struct *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 defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
        VM_BUG_ON_MM(mm->pmd_huge_pte, mm);

diff --git a/mm/debug.c b/mm/debug.c
index 6726bec731c956e904450a9f67e22fc7be8f049c..a12d826bb774c0f333ca7fabc6119d63ef8cc7ee 100644 (file)
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -105,7 +105,8 @@ 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 nr_pmds %lu map_count %d\n"
+               "pgd %p mm_users %d mm_count %d\n"
+               "nr_ptes %lu nr_pmds %lu nr_puds %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"
@@ -136,7 +137,8 @@ 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_nr_pmds(mm),
+               mm_nr_puds(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 --git a/mm/memory.c b/mm/memory.c
index 42fb30300bb51a0a79942df7df3c04271e41e03b..6bbd4078ec98962cc46c3f1f3c344a74c2ca4a0f 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -506,6 +506,7 @@ static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
        pud = pud_offset(p4d, start);
        p4d_clear(p4d);
        pud_free_tlb(tlb, pud, start);
+       mm_dec_nr_puds(tlb->mm);
 }
 
 static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd,
@@ -4149,15 +4150,17 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address)
 
        spin_lock(&mm->page_table_lock);
 #ifndef __ARCH_HAS_5LEVEL_HACK
-       if (p4d_present(*p4d))          /* Another has populated it */
-               pud_free(mm, new);
-       else
+       if (!p4d_present(*p4d)) {
+               mm_inc_nr_puds(mm);
                p4d_populate(mm, p4d, new);
-#else
-       if (pgd_present(*p4d))          /* Another has populated it */
+       } else  /* Another has populated it */
                pud_free(mm, new);
-       else
+#else
+       if (!pgd_present(*p4d)) {
+               mm_inc_nr_puds(mm);
                pgd_populate(mm, p4d, new);
+       } else  /* Another has populated it */
+               pud_free(mm, new);
 #endif /* __ARCH_HAS_5LEVEL_HACK */
        spin_unlock(&mm->page_table_lock);
        return 0;

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3023919970f7468ae89ebba14f59b8aa0cd53eaa..f642a45b7f14b1f1d975d84ecaab332ceaedabcd 100644 (file)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -221,7 +221,8 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
         * task's rss, pagetable and swap space use.
         */
        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);
+               atomic_long_read(&p->mm->nr_ptes) + mm_nr_pmds(p->mm) +
+               mm_nr_puds(p->mm);
        task_unlock(p);
 
        /*
@@ -397,7 +398,7 @@ 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 swapents oom_score_adj name\n");
+       pr_info("[ pid ]   uid  tgid total_vm      rss nr_ptes nr_pmds nr_puds swapents oom_score_adj name\n");
        rcu_read_lock();
        for_each_process(p) {
                if (oom_unkillable_task(p, memcg, nodemask))
@@ -413,11 +414,12 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
                        continue;
                }
 
-               pr_info("[%5d] %5d %5d %8lu %8lu %7ld %7ld %8lu         %5hd %s\n",
+               pr_info("[%5d] %5d %5d %8lu %8lu %7ld %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),
+                       mm_nr_puds(task->mm),
                        get_mm_counter(task->mm, MM_SWAPENTS),
                        task->signal->oom_score_adj, task->comm);
                task_unlock(task);