From b084d4353ff99d824d3bc5a5c2c22c70b1fba722 Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Fri, 5 Mar 2010 13:41:42 -0800
Subject: [PATCH] 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>
---
Documentation/filesystems/proc.txt | 2 ++
fs/proc/task_mmu.c | 9 ++++++---
include/linux/mm_types.h | 1 +
mm/memory.c | 16 ++++++++++++----
mm/rmap.c | 1 +
mm/swapfile.c | 1 +
6 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index e418f3d8f427..b5c5fc657a88 100644
--- 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
+ VmSwap: 0 kB
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
+ 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
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 375581276011..183f8ff5f400 100644
--- 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)
{
- unsigned long data, text, lib;
+ unsigned long data, text, lib, swap;
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;
+ swap = get_mm_counter(mm, MM_SWAPENTS);
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"
- "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),
@@ -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,
- (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)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 21861239ab0c..19549d7275ab 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -198,6 +198,7 @@ struct core_state {
enum {
MM_FILEPAGES,
MM_ANONPAGES,
+ MM_SWAPENTS,
NR_MM_COUNTERS
};
diff --git a/mm/memory.c b/mm/memory.c
index a4597614f18d..77d9f840936b 100644
--- 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);
}
- 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
@@ -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);
- } 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));
@@ -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);
+ 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);
diff --git a/mm/rmap.c b/mm/rmap.c
index 73d0472884c2..5cb47111f79e 100644
--- 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);
+ inc_mm_counter(mm, MM_SWAPENTS);
} 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 893984946a2c..187a21f8b7bd 100644
--- 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;
}
+ 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,