[RFC][-mm][PATCH 2/6] oom-killer: count swap usage per process.

KAMEZAWA Hiroyuki
2009-11-02T07:28:03Z

From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Now, anon_rss and file_rss is counted as RSS and exported via /proc.
RSS usage is important information but one more information which
is often asked by users is "usage of swap".(user support team said.)

This patch counts swap entry usage per process and show it via
/proc/<pid>/status. I think status file is robust against new entry.
Then, it is the first candidate..

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
fs/proc/task_mmu.c | 10 +++++++---
include/linux/mm_types.h | 1 +
mm/memory.c | 30 +++++++++++++++++++++---------
mm/rmap.c | 1 +
mm/swapfile.c | 1 +
5 files changed, 31 insertions(+), 12 deletions(-)

Index: mmotm-2.6.32-Nov2/include/linux/mm_types.h
===================================================================
--- mmotm-2.6.32-Nov2.orig/include/linux/mm_types.h
+++ mmotm-2.6.32-Nov2/include/linux/mm_types.h
@@ -228,6 +228,7 @@ struct mm_struct {
*/
mm_counter_t _file_rss;
mm_counter_t _anon_rss;
+ mm_counter_t _swap_usage;

unsigned long hiwater_rss; /* High-watermark of RSS usage */
unsigned long hiwater_vm; /* High-water virtual memory usage */
Index: mmotm-2.6.32-Nov2/mm/memory.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/mm/memory.c
+++ mmotm-2.6.32-Nov2/mm/memory.c
@@ -376,12 +376,15 @@ int __pte_alloc_kernel(pmd_t *pmd, unsig
return 0;
}

-static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
+static inline void
+add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss, int swap_usage)
{
if (file_rss)
add_mm_counter(mm, file_rss, file_rss);
if (anon_rss)
add_mm_counter(mm, anon_rss, anon_rss);
+ if (swap_usage)
+ add_mm_counter(mm, swap_usage, swap_usage);
}

/*
@@ -597,7 +600,9 @@ copy_one_pte(struct mm_struct *dst_mm, s
&src_mm->mmlist);
spin_unlock(&mmlist_lock);
}
- if (is_write_migration_entry(entry) &&
+ if (!is_migration_entry(entry))
+ rss[2]++;
+ else if (is_write_migration_entry(entry) &&
is_cow_mapping(vm_flags)) {
/*
* COW mappings require pages in both parent
@@ -648,11 +653,11 @@ static int copy_pte_range(struct mm_stru
pte_t *src_pte, *dst_pte;
spinlock_t *src_ptl, *dst_ptl;
int progress = 0;
- int rss[2];
+ int rss[3];
swp_entry_t entry = (swp_entry_t){0};

again:
- rss[1] = rss[0] = 0;
+ rss[2] = rss[1] = rss[0] = 0;
dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
if (!dst_pte)
return -ENOMEM;
@@ -688,7 +693,7 @@ again:
arch_leave_lazy_mmu_mode();
spin_unlock(src_ptl);
pte_unmap_nested(orig_src_pte);
- add_mm_rss(dst_mm, rss[0], rss[1]);
+ add_mm_rss(dst_mm, rss[0], rss[1], rss[2]);
pte_unmap_unlock(orig_dst_pte, dst_ptl);
cond_resched();

@@ -818,6 +823,7 @@ static unsigned long zap_pte_range(struc
spinlock_t *ptl;
int file_rss = 0;
int anon_rss = 0;
+ int swap_usage = 0;

pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
arch_enter_lazy_mmu_mode();
@@ -887,13 +893,18 @@ static unsigned long zap_pte_range(struc
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 ent = pte_to_swp_entry(ptent);
+
+ if (!is_migration_entry(ent))
+ swap_usage--;
+ if (unlikely(!free_swap_and_cache(ent)))
+ 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));

- add_mm_rss(mm, file_rss, anon_rss);
+ add_mm_rss(mm, file_rss, anon_rss, swap_usage);
arch_leave_lazy_mmu_mode();
pte_unmap_unlock(pte - 1, ptl);

@@ -2595,6 +2606,7 @@ static int do_swap_page(struct mm_struct
*/

inc_mm_counter(mm, anon_rss);
+ dec_mm_counter(mm, swap_usage);
pte = mk_pte(page, vma->vm_page_prot);
if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
pte = maybe_mkwrite(pte_mkdirty(pte), vma);
Index: mmotm-2.6.32-Nov2/mm/swapfile.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/mm/swapfile.c
+++ mmotm-2.6.32-Nov2/mm/swapfile.c
@@ -837,6 +837,7 @@ static int unuse_pte(struct vm_area_stru
}

inc_mm_counter(vma->vm_mm, anon_rss);
+ dec_mm_counter(vma->vm_mm, swap_usage);
get_page(page);
set_pte_at(vma->vm_mm, addr, pte,
pte_mkold(mk_pte(page, vma->vm_page_prot)));
Index: mmotm-2.6.32-Nov2/fs/proc/task_mmu.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/fs/proc/task_mmu.c
+++ mmotm-2.6.32-Nov2/fs/proc/task_mmu.c
@@ -17,7 +17,7 @@
void task_mem(struct seq_file *m, struct mm_struct *mm)
{
unsigned long data, text, lib;
- unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
+ unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss, swap;

/*
* Note: to minimize their overhead, mm maintains hiwater_vm and
@@ -36,6 +36,8 @@ void task_mem(struct seq_file *m, struct
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, swap_usage);
seq_printf(m,
"VmPeak:\t%8lu kB\n"
"VmSize:\t%8lu kB\n"
@@ -46,7 +48,8 @@ void task_mem(struct seq_file *m, struct
"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 +57,8 @@ void task_mem(struct seq_file *m, struct
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)
Index: mmotm-2.6.32-Nov2/mm/rmap.c
===================================================================
--- mmotm-2.6.32-Nov2.orig/mm/rmap.c
+++ mmotm-2.6.32-Nov2/mm/rmap.c
@@ -834,6 +834,7 @@ static int try_to_unmap_one(struct page
spin_unlock(&mmlist_lock);
}
dec_mm_counter(mm, anon_rss);
+ inc_mm_counter(mm, swap_usage);
} else if (PAGE_MIGRATION) {
/*
* Store the pfn of the page in a special migration