mm: count swap usage

A frequent questions from users about memory management is what numbers of
swap ents are user for processes.  And this information will give some
hints to oom-killer.

Besides we can count the number of swapents per a process by scanning
/proc/<pid>/smaps, this is very slow and not good for usual process
information handler which works like 'ps' or 'top'.  (ps or top is now
enough slow..)

This patch adds a counter of swapents to mm_counter and update is at each
swap events.  Information is exported via /proc/<pid>/status file as

[kamezawa@bluextal memory]$ cat /proc/self/status
Name:   cat
State:  R (running)
Tgid:   2910
Pid:    2910
PPid:   2823
TracerPid:      0
Uid:    500     500     500     500
Gid:    500     500     500     500
FDSize: 256
Groups: 500
VmPeak:    82696 kB
VmSize:    82696 kB
VmLck:         0 kB
VmHWM:       432 kB
VmRSS:       432 kB
VmData:      172 kB
VmStk:        84 kB
VmExe:        48 kB
VmLib:      1568 kB
VmPTE:        40 kB
VmSwap:        0 kB <=============== this.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index e418f3d8f427acf4d252bf71aa201c644dadcab8..b5c5fc657a88073ec3640738fa6d582aef2b60b5 100644 (file)
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -164,6 +164,7 @@ read the file /proc/PID/status:
   VmExe:        68 kB
   VmLib:      1412 kB
   VmPTE:        20 kb
   VmExe:        68 kB
   VmLib:      1412 kB
   VmPTE:        20 kb

+  VmSwap:        0 kB

   Threads:        1
   SigQ:   0/28578
   SigPnd: 0000000000000000
   Threads:        1
   SigQ:   0/28578
   SigPnd: 0000000000000000


@@ -219,6 +220,7 @@ Table 1-2: Contents of the statm files (as of 2.6.30-rc7)
  VmExe                       size of text segment
  VmLib                       size of shared library code
  VmPTE                       size of page table entries
  VmExe                       size of text segment
  VmLib                       size of shared library code
  VmPTE                       size of page table entries

+ VmSwap                      size of swap usage (the number of referred swapents)

  Threads                     number of threads
  SigQ                        number of signals queued/max. number for queue
  SigPnd                      bitmap of pending signals for the thread
  Threads                     number of threads
  SigQ                        number of signals queued/max. number for queue
  SigPnd                      bitmap of pending signals for the thread

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 37558127601180a48c39a84cd9794d69a2bc08df..183f8ff5f400b90d8b128465551d8157004f20d2 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -16,7 +16,7 @@
 
 void task_mem(struct seq_file *m, struct mm_struct *mm)
 {
 
 void task_mem(struct seq_file *m, struct mm_struct *mm)
 {

-       unsigned long data, text, lib;
+       unsigned long data, text, lib, swap;

        unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
 
        /*
        unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
 
        /*


@@ -36,6 +36,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
        data = mm->total_vm - mm->shared_vm - mm->stack_vm;
        text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
        lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
        data = mm->total_vm - mm->shared_vm - mm->stack_vm;
        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);

        seq_printf(m,
                "VmPeak:\t%8lu kB\n"
                "VmSize:\t%8lu kB\n"
        seq_printf(m,
                "VmPeak:\t%8lu kB\n"
                "VmSize:\t%8lu kB\n"


@@ -46,7 +47,8 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                "VmStk:\t%8lu kB\n"
                "VmExe:\t%8lu kB\n"
                "VmLib:\t%8lu kB\n"
                "VmStk:\t%8lu kB\n"
                "VmExe:\t%8lu kB\n"
                "VmLib:\t%8lu kB\n"

-               "VmPTE:\t%8lu kB\n",
+               "VmPTE:\t%8lu kB\n"
+               "VmSwap:\t%8lu kB\n",

                hiwater_vm << (PAGE_SHIFT-10),
                (total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
                mm->locked_vm << (PAGE_SHIFT-10),
                hiwater_vm << (PAGE_SHIFT-10),
                (total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
                mm->locked_vm << (PAGE_SHIFT-10),


@@ -54,7 +56,8 @@ 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,
                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)*mm->nr_ptes) >> 10,
+               swap << (PAGE_SHIFT-10));

 }
 
 unsigned long task_vsize(struct mm_struct *mm)
 }
 
 unsigned long task_vsize(struct mm_struct *mm)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 21861239ab0cb15f0eb82428aafa04049b255f12..19549d7275abb52c2f964c4b28707f5e93335ebc 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -198,6 +198,7 @@ struct core_state {
 enum {
        MM_FILEPAGES,
        MM_ANONPAGES,
 enum {
        MM_FILEPAGES,
        MM_ANONPAGES,

+       MM_SWAPENTS,

        NR_MM_COUNTERS
 };
 
        NR_MM_COUNTERS
 };
 

diff --git a/mm/memory.c b/mm/memory.c
index a4597614f18d8034cd274b91a7be91ef5d134580..77d9f840936b29304773932e76f3d1103eee01ac 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -679,7 +679,9 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
                                                 &src_mm->mmlist);
                                spin_unlock(&mmlist_lock);
                        }
                                                 &src_mm->mmlist);
                                spin_unlock(&mmlist_lock);
                        }

-                       if (is_write_migration_entry(entry) &&
+                       if (likely(!non_swap_entry(entry)))
+                               rss[MM_SWAPENTS]++;
+                       else if (is_write_migration_entry(entry) &&

                                        is_cow_mapping(vm_flags)) {
                                /*
                                 * COW mappings require pages in both parent
                                        is_cow_mapping(vm_flags)) {
                                /*
                                 * COW mappings require pages in both parent


@@ -974,9 +976,14 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
                if (pte_file(ptent)) {
                        if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
                                print_bad_pte(vma, addr, ptent, NULL);
                if (pte_file(ptent)) {
                        if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
                                print_bad_pte(vma, addr, ptent, NULL);

-               } else if
-                 (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent))))
-                       print_bad_pte(vma, addr, ptent, NULL);
+               } else {
+                       swp_entry_t entry = pte_to_swp_entry(ptent);
+
+                       if (!non_swap_entry(entry))
+                               rss[MM_SWAPENTS]--;
+                       if (unlikely(!free_swap_and_cache(entry)))
+                               print_bad_pte(vma, addr, ptent, NULL);
+               }

                pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
        } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
 
                pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
        } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
 


@@ -2692,6 +2699,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
         */
 
        inc_mm_counter_fast(mm, MM_ANONPAGES);
         */
 
        inc_mm_counter_fast(mm, MM_ANONPAGES);

+       dec_mm_counter_fast(mm, MM_SWAPENTS);

        pte = mk_pte(page, vma->vm_page_prot);
        if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
                pte = maybe_mkwrite(pte_mkdirty(pte), vma);
        pte = mk_pte(page, vma->vm_page_prot);
        if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
                pte = maybe_mkwrite(pte_mkdirty(pte), vma);

diff --git a/mm/rmap.c b/mm/rmap.c
index 73d0472884c226fa6682350621b6eea142e2e1c9..5cb47111f79e1e25fe539d3ceca3482e5bc6887f 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -840,6 +840,7 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                                spin_unlock(&mmlist_lock);
                        }
                        dec_mm_counter(mm, MM_ANONPAGES);
                                spin_unlock(&mmlist_lock);
                        }
                        dec_mm_counter(mm, MM_ANONPAGES);

+                       inc_mm_counter(mm, MM_SWAPENTS);

                } else if (PAGE_MIGRATION) {
                        /*
                         * Store the pfn of the page in a special migration
                } else if (PAGE_MIGRATION) {
                        /*
                         * Store the pfn of the page in a special migration

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 893984946a2cd808bb7da825da0a0b6c32b811a1..187a21f8b7bdf2d4d5b99b8c51927c56e7ee80d7 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -840,6 +840,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
                goto out;
        }
 
                goto out;
        }
 

+       dec_mm_counter(vma->vm_mm, MM_SWAPENTS);

        inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
        get_page(page);
        set_pte_at(vma->vm_mm, addr, pte,
        inc_mm_counter(vma->vm_mm, MM_ANONPAGES);
        get_page(page);
        set_pte_at(vma->vm_mm, addr, pte,