From e1f56c89b040134add93f686931cc266541d239a Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 14 Nov 2013 14:30:48 -0800 Subject: [PATCH] mm: convert mm->nr_ptes to atomic_long_t With split page table lock for PMD level we can't hold mm->page_table_lock while updating nr_ptes. Let's convert it to atomic_long_t to avoid races. Signed-off-by: Kirill A. Shutemov Tested-by: Alex Thorlton Cc: Ingo Molnar Cc: Naoya Horiguchi Cc: "Eric W . Biederman" Cc: "Paul E . McKenney" Cc: Al Viro Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Dave Hansen Cc: Dave Jones Cc: David Howells Cc: Frederic Weisbecker Cc: Johannes Weiner Cc: Kees Cook Cc: Mel Gorman Cc: Michael Kerrisk Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Robin Holt Cc: Sedat Dilek Cc: Srikar Dronamraju Cc: Thomas Gleixner Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_mmu.c | 3 ++- include/linux/mm_types.h | 2 +- kernel/fork.c | 2 +- mm/huge_memory.c | 10 +++++----- mm/memory.c | 4 ++-- mm/mmap.c | 3 ++- mm/oom_kill.c | 6 +++--- 7 files changed, 16 insertions(+), 14 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index abbe825d20ff..8faaebdc6b02 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -62,7 +62,8 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) total_rss << (PAGE_SHIFT-10), data << (PAGE_SHIFT-10), mm->stack_vm << (PAGE_SHIFT-10), text, lib, - (PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10, + (PTRS_PER_PTE * sizeof(pte_t) * + atomic_long_read(&mm->nr_ptes)) >> 10, swap << (PAGE_SHIFT-10)); } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index f1ff66dfa79e..566df579c51f 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -339,6 +339,7 @@ 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 */ int map_count; /* number of VMAs */ spinlock_t page_table_lock; /* Protects page tables and some counters */ @@ -360,7 +361,6 @@ struct mm_struct { unsigned long exec_vm; /* VM_EXEC & ~VM_WRITE */ unsigned long stack_vm; /* VM_GROWSUP/DOWN */ unsigned long def_flags; - unsigned long nr_ptes; /* Page table pages */ unsigned long start_code, end_code, start_data, end_data; unsigned long start_brk, brk, start_stack; unsigned long arg_start, arg_end, env_start, env_end; diff --git a/kernel/fork.c b/kernel/fork.c index f6d11fc67f72..e2520756e005 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -532,7 +532,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) mm->flags = (current->mm) ? (current->mm->flags & MMF_INIT_MASK) : default_dump_filter; mm->core_state = NULL; - mm->nr_ptes = 0; + atomic_long_set(&mm->nr_ptes, 0); memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); spin_lock_init(&mm->page_table_lock); mm_init_aio(mm); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 0556c6a44959..e5b2d316be2e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -738,7 +738,7 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, haddr, pmd, entry); add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); - mm->nr_ptes++; + atomic_long_inc(&mm->nr_ptes); spin_unlock(&mm->page_table_lock); } @@ -771,7 +771,7 @@ static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, entry = pmd_mkhuge(entry); pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, haddr, pmd, entry); - mm->nr_ptes++; + atomic_long_inc(&mm->nr_ptes); return true; } @@ -896,7 +896,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, pmd = pmd_mkold(pmd_wrprotect(pmd)); pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable); set_pmd_at(dst_mm, addr, dst_pmd, pmd); - dst_mm->nr_ptes++; + atomic_long_inc(&dst_mm->nr_ptes); ret = 0; out_unlock: @@ -1392,7 +1392,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, tlb_remove_pmd_tlb_entry(tlb, pmd, addr); pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); if (is_huge_zero_pmd(orig_pmd)) { - tlb->mm->nr_ptes--; + atomic_long_dec(&tlb->mm->nr_ptes); spin_unlock(&tlb->mm->page_table_lock); put_huge_zero_page(); } else { @@ -1401,7 +1401,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, VM_BUG_ON(page_mapcount(page) < 0); add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); VM_BUG_ON(!PageHead(page)); - tlb->mm->nr_ptes--; + atomic_long_dec(&tlb->mm->nr_ptes); spin_unlock(&tlb->mm->page_table_lock); tlb_remove_page(tlb, page); } diff --git a/mm/memory.c b/mm/memory.c index bf8665849a5f..0b5a93a49f27 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -382,7 +382,7 @@ static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, pgtable_t token = pmd_pgtable(*pmd); pmd_clear(pmd); pte_free_tlb(tlb, token, addr); - tlb->mm->nr_ptes--; + atomic_long_dec(&tlb->mm->nr_ptes); } static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, @@ -573,7 +573,7 @@ int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, spin_lock(&mm->page_table_lock); wait_split_huge_page = 0; if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ - mm->nr_ptes++; + atomic_long_inc(&mm->nr_ptes); pmd_populate(mm, pmd, new); new = NULL; } else if (unlikely(pmd_trans_splitting(*pmd))) diff --git a/mm/mmap.c b/mm/mmap.c index 5a6baddde15d..834b2d785f1e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2724,7 +2724,8 @@ void exit_mmap(struct mm_struct *mm) } vm_unacct_memory(nr_accounted); - WARN_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); + WARN_ON(atomic_long_read(&mm->nr_ptes) > + (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); } /* Insert vm structure into process list sorted by address diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 6738c47f1f72..1e4a600a6163 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -161,7 +161,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, * 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) + p->mm->nr_ptes + + points = get_mm_rss(p->mm) + atomic_long_read(&p->mm->nr_ptes) + get_mm_counter(p->mm, MM_SWAPENTS); task_unlock(p); @@ -364,10 +364,10 @@ static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemas continue; } - pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu %5hd %s\n", + pr_info("[%5d] %5d %5d %8lu %8lu %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), - task->mm->nr_ptes, + atomic_long_read(&task->mm->nr_ptes), get_mm_counter(task->mm, MM_SWAPENTS), task->signal->oom_score_adj, task->comm); task_unlock(task); -- 2.20.1