Table 1-1: Process specific entries in /proc
..............................................................................
- File Content
- cmdline Command line arguments
- cpu Current and last cpu in which it was executed (2.4)(smp)
- cwd Link to the current working directory
- environ Values of environment variables
- exe Link to the executable of this process
- fd Directory, which contains all file descriptors
- maps Memory maps to executables and library files (2.4)
- mem Memory held by this process
- root Link to the root directory of this process
- stat Process status
- statm Process memory status information
- status Process status in human readable form
- wchan If CONFIG_KALLSYMS is set, a pre-decoded wchan
- smaps Extension based on maps, presenting the rss size for each mapped file
+ File Content
+ clear_refs Clears page referenced bits shown in smaps output
+ cmdline Command line arguments
+ cpu Current and last cpu in which it was executed (2.4)(smp)
+ cwd Link to the current working directory
+ environ Values of environment variables
+ exe Link to the executable of this process
+ fd Directory, which contains all file descriptors
+ maps Memory maps to executables and library files (2.4)
+ mem Memory held by this process
+ root Link to the root directory of this process
+ stat Process status
+ statm Process memory status information
+ status Process status in human readable form
+ wchan If CONFIG_KALLSYMS is set, a pre-decoded wchan
+ smaps Extension based on maps, the rss size for each mapped file
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For example, to get the status information of a process, all you have to do is
.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,
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
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
"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,
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;
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;
}
}
-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;
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;
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);
}
}
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;
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