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Commit b084d435 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds
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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: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: default avatarChristoph Lameter <cl@linux-foundation.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 34e55232

Documentation/filesystems/proc.txt

+2 −0
Original line number Original line Diff line number Diff line
@@ -164,6 +164,7 @@ read the file /proc/PID/status: 
  VmExe:        68 kB

  VmExe:        68 kB

  VmLib:      1412 kB

  VmLib:      1412 kB

  VmPTE:        20 kb

  VmPTE:        20 kb

  VmSwap:        0 kB

  Threads:        1

  Threads:        1

  SigQ:   0/28578

  SigQ:   0/28578

  SigPnd: 0000000000000000

  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

 VmExe                       size of text segment

 VmLib                       size of shared library code

 VmLib                       size of shared library code

 VmPTE                       size of page table entries

 VmPTE                       size of page table entries

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

 Threads                     number of threads

 Threads                     number of threads

 SigQ                        number of signals queued/max. number for queue

 SigQ                        number of signals queued/max. number for queue

 SigPnd                      bitmap of pending signals for the thread

 SigPnd                      bitmap of pending signals for the thread

fs/proc/task_mmu.c

+6 −3
Original line number Original line Diff line number Diff line
@@ -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;

	data = mm->total_vm - mm->shared_vm - mm->stack_vm;

	text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;

	text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;

	lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;

	lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;

	swap = get_mm_counter(mm, MM_SWAPENTS);

	seq_printf(m,

	seq_printf(m,

		"VmPeak:\t%8lu kB\n"

		"VmPeak:\t%8lu kB\n"

		"VmSize:\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"

		"VmStk:\t%8lu kB\n"

		"VmExe:\t%8lu kB\n"

		"VmExe:\t%8lu kB\n"

		"VmLib:\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),

		hiwater_vm << (PAGE_SHIFT-10),

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

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

		mm->locked_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),

		total_rss << (PAGE_SHIFT-10),

		data << (PAGE_SHIFT-10),

		data << (PAGE_SHIFT-10),

		mm->stack_vm << (PAGE_SHIFT-10), text, lib,

		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)

include/linux/mm_types.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -198,6 +198,7 @@ struct core_state { 
enum {

enum {

	MM_FILEPAGES,

	MM_FILEPAGES,

	MM_ANONPAGES,

	MM_ANONPAGES,

	MM_SWAPENTS,

	NR_MM_COUNTERS

	NR_MM_COUNTERS

};

};

mm/memory.c

+12 −4
Original line number Original line Diff line number Diff line
@@ -679,7 +679,9 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 
						 &src_mm->mmlist);

						 &src_mm->mmlist);

				spin_unlock(&mmlist_lock);

				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)) {

					is_cow_mapping(vm_flags)) {

				/*

				/*

				 * COW mappings require pages in both parent

				 * 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 (pte_file(ptent)) {

			if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))

			if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))

				print_bad_pte(vma, addr, ptent, NULL);

				print_bad_pte(vma, addr, ptent, NULL);

		} else if

		} else {

		  (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent))))

			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);

				print_bad_pte(vma, addr, ptent, NULL);

		}

		pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);

		pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);

	} while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));

	} 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);

	pte = mk_pte(page, vma->vm_page_prot);

	if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {

	if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {

		pte = maybe_mkwrite(pte_mkdirty(pte), vma);

		pte = maybe_mkwrite(pte_mkdirty(pte), vma);

mm/rmap.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -840,6 +840,7 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, 
				spin_unlock(&mmlist_lock);

				spin_unlock(&mmlist_lock);

			}

			}

			dec_mm_counter(mm, MM_ANONPAGES);

			dec_mm_counter(mm, MM_ANONPAGES);

			inc_mm_counter(mm, MM_SWAPENTS);

		} else if (PAGE_MIGRATION) {

		} else if (PAGE_MIGRATION) {

			/*

			/*

			 * Store the pfn of the page in a special migration

			 * Store the pfn of the page in a special migration