diff options
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/base.c | 36 | ||||
| -rw-r--r-- | fs/proc/task_mmu.c | 79 |
2 files changed, 99 insertions, 16 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 989af5e55d1..ec158dd02b3 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -715,6 +715,40 @@ static const struct file_operations proc_oom_adjust_operations = { .write = oom_adjust_write, }; +static ssize_t clear_refs_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct task_struct *task; + char buffer[PROC_NUMBUF], *end; + struct mm_struct *mm; + + memset(buffer, 0, sizeof(buffer)); + if (count > sizeof(buffer) - 1) + count = sizeof(buffer) - 1; + if (copy_from_user(buffer, buf, count)) + return -EFAULT; + if (!simple_strtol(buffer, &end, 0)) + return -EINVAL; + if (*end == '\n') + end++; + task = get_proc_task(file->f_path.dentry->d_inode); + if (!task) + return -ESRCH; + mm = get_task_mm(task); + if (mm) { + clear_refs_smap(mm); + mmput(mm); + } + put_task_struct(task); + if (end - buffer == 0) + return -EIO; + return end - buffer; +} + +static struct file_operations proc_clear_refs_operations = { + .write = clear_refs_write, +}; + #ifdef CONFIG_AUDITSYSCALL #define TMPBUFLEN 21 static ssize_t proc_loginuid_read(struct file * file, char __user * buf, @@ -1851,6 +1885,7 @@ static struct pid_entry tgid_base_stuff[] = { REG("mounts", S_IRUGO, mounts), REG("mountstats", S_IRUSR, mountstats), #ifdef CONFIG_MMU + REG("clear_refs", S_IWUSR, clear_refs), REG("smaps", S_IRUGO, smaps), #endif #ifdef CONFIG_SECURITY @@ -2132,6 +2167,7 @@ static struct pid_entry tid_base_stuff[] = { LNK("exe", exe), REG("mounts", S_IRUGO, mounts), #ifdef CONFIG_MMU + REG("clear_refs", S_IWUSR, clear_refs), REG("smaps", S_IRUGO, smaps), #endif #ifdef CONFIG_SECURITY diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 199088ee969..4008c060f7e 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -195,7 +195,7 @@ static int show_map_internal(struct seq_file *m, void *v, struct mem_size_stats "Shared_Dirty: %8lu kB\n" "Private_Clean: %8lu kB\n" "Private_Dirty: %8lu kB\n" - "Pgs_Referenced: %8lu kB\n", + "Referenced: %8lu kB\n", (vma->vm_end - vma->vm_start) >> 10, mss->resident >> 10, mss->shared_clean >> 10, @@ -214,9 +214,9 @@ static int show_map(struct seq_file *m, void *v) return show_map_internal(m, v, NULL); } -static void smaps_one_pmd(struct vm_area_struct *vma, pmd_t *pmd, - unsigned long addr, unsigned long end, - void *private) +static void smaps_pte_range(struct vm_area_struct *vma, pmd_t *pmd, + unsigned long addr, unsigned long end, + void *private) { struct mem_size_stats *mss = private; pte_t *pte, ptent; @@ -254,8 +254,34 @@ static void smaps_one_pmd(struct vm_area_struct *vma, pmd_t *pmd, cond_resched(); } -static inline void for_each_pmd_in_pud(struct pmd_walker *walker, pud_t *pud, - unsigned long addr, unsigned long end) +static void clear_refs_pte_range(struct vm_area_struct *vma, pmd_t *pmd, + unsigned long addr, unsigned long end, + void *private) +{ + pte_t *pte, ptent; + spinlock_t *ptl; + struct page *page; + + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (; addr != end; pte++, addr += PAGE_SIZE) { + ptent = *pte; + if (!pte_present(ptent)) + continue; + + page = vm_normal_page(vma, addr, ptent); + if (!page) + continue; + + /* Clear accessed and referenced bits. */ + ptep_test_and_clear_young(vma, addr, pte); + ClearPageReferenced(page); + } + pte_unmap_unlock(pte - 1, ptl); + cond_resched(); +} + +static inline void walk_pmd_range(struct pmd_walker *walker, pud_t *pud, + unsigned long addr, unsigned long end) { pmd_t *pmd; unsigned long next; @@ -269,8 +295,8 @@ static inline void for_each_pmd_in_pud(struct pmd_walker *walker, pud_t *pud, } } -static inline void for_each_pud_in_pgd(struct pmd_walker *walker, pgd_t *pgd, - unsigned long addr, unsigned long end) +static inline void walk_pud_range(struct pmd_walker *walker, pgd_t *pgd, + unsigned long addr, unsigned long end) { pud_t *pud; unsigned long next; @@ -280,15 +306,24 @@ static inline void for_each_pud_in_pgd(struct pmd_walker *walker, pgd_t *pgd, next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - for_each_pmd_in_pud(walker, pud, addr, next); + walk_pmd_range(walker, pud, addr, next); } } -static inline void for_each_pmd(struct vm_area_struct *vma, - void (*action)(struct vm_area_struct *, pmd_t *, - unsigned long, unsigned long, - void *), - void *private) +/* + * walk_page_range - walk the page tables of a VMA with a callback + * @vma - VMA to walk + * @action - callback invoked for every bottom-level (PTE) page table + * @private - private data passed to the callback function + * + * Recursively walk the page table for the memory area in a VMA, calling + * a callback for every bottom-level (PTE) page table. + */ +static inline void walk_page_range(struct vm_area_struct *vma, + void (*action)(struct vm_area_struct *, + pmd_t *, unsigned long, + unsigned long, void *), + void *private) { unsigned long addr = vma->vm_start; unsigned long end = vma->vm_end; @@ -305,7 +340,7 @@ static inline void for_each_pmd(struct vm_area_struct *vma, next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; - for_each_pud_in_pgd(&walker, pgd, addr, next); + walk_pud_range(&walker, pgd, addr, next); } } @@ -316,10 +351,22 @@ static int show_smap(struct seq_file *m, void *v) memset(&mss, 0, sizeof mss); if (vma->vm_mm && !is_vm_hugetlb_page(vma)) - for_each_pmd(vma, smaps_one_pmd, &mss); + walk_page_range(vma, smaps_pte_range, &mss); return show_map_internal(m, v, &mss); } +void clear_refs_smap(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + + down_read(&mm->mmap_sem); + for (vma = mm->mmap; vma; vma = vma->vm_next) + if (vma->vm_mm && !is_vm_hugetlb_page(vma)) + walk_page_range(vma, clear_refs_pte_range, NULL); + flush_tlb_mm(mm); + up_read(&mm->mmap_sem); +} + static void *m_start(struct seq_file *m, loff_t *pos) { struct proc_maps_private *priv = m->private; |