Messages in this thread Patch in this message | | | Date | Tue, 15 Dec 2009 18:14:13 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [mmotm][PATCH 3/5] mm: count swap usage |
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One of 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.
Changelog: 2009/12/14 - removed a bad comment. - Added Documentation
Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- 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(-)
Index: mmotm-2.6.32-Dec8-pth/include/linux/mm_types.h =================================================================== --- mmotm-2.6.32-Dec8-pth.orig/include/linux/mm_types.h +++ mmotm-2.6.32-Dec8-pth/include/linux/mm_types.h @@ -196,6 +196,7 @@ struct core_state { enum { MM_FILEPAGES, MM_ANONPAGES, + MM_SWAPENTS, NR_MM_COUNTERS }; Index: mmotm-2.6.32-Dec8-pth/mm/memory.c =================================================================== --- mmotm-2.6.32-Dec8-pth.orig/mm/memory.c +++ mmotm-2.6.32-Dec8-pth/mm/memory.c @@ -679,7 +679,9 @@ copy_one_pte(struct mm_struct *dst_mm, s &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(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 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)); @@ -2688,6 +2695,7 @@ static int do_swap_page(struct mm_struct */ 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); Index: mmotm-2.6.32-Dec8-pth/mm/rmap.c =================================================================== --- mmotm-2.6.32-Dec8-pth.orig/mm/rmap.c +++ mmotm-2.6.32-Dec8-pth/mm/rmap.c @@ -840,6 +840,7 @@ int try_to_unmap_one(struct page *page, 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 Index: mmotm-2.6.32-Dec8-pth/mm/swapfile.c =================================================================== --- mmotm-2.6.32-Dec8-pth.orig/mm/swapfile.c +++ mmotm-2.6.32-Dec8-pth/mm/swapfile.c @@ -840,6 +840,7 @@ static int unuse_pte(struct vm_area_stru 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, Index: mmotm-2.6.32-Dec8-pth/fs/proc/task_mmu.c =================================================================== --- mmotm-2.6.32-Dec8-pth.orig/fs/proc/task_mmu.c +++ mmotm-2.6.32-Dec8-pth/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 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 "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 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-Dec8-pth/Documentation/filesystems/proc.txt =================================================================== --- mmotm-2.6.32-Dec8-pth.orig/Documentation/filesystems/proc.txt +++ mmotm-2.6.32-Dec8-pth/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 @@ -220,6 +221,7 @@ Table 1-2: Contents of the statm files ( 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
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