Re: [PATCH] show per-process swap usage via procfs
From: Minchan Kim
Date: Thu Nov 05 2009 - 10:11:41 EST
Hi, Kame.
On Wed, Nov 4, 2009 at 3:24 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>
> Passed several tests and one bug was fixed since RFC version.
> This patch is against mmotm.
> =
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> 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..
>
> After this, /proc/<pid>/status includes following line
> <snip>
> VmPeak: 315360 kB
> VmSize: 315360 kB
> VmLck: 0 kB
> VmHWM: 180452 kB
> VmRSS: 180452 kB
> VmData: 311624 kB
> VmStk: 84 kB
> VmExe: 4 kB
> VmLib: 1568 kB
> VmPTE: 640 kB
> VmSwap: 131240 kB <=== new information
>
> Note:
> Because this patch catches swap_pte on page table, this will
> not catch shmem's swapout. It's already accounted in per-shmem
> inode and we don't need to do more.
>
> Changelog: 2009/11/03
> - clean up.
> - fixed initialization bug at fork (init_mm())
>
> Acked-by: Acked-by; David Rientjes <rientjes@xxxxxxxxxx>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
> fs/proc/task_mmu.c | 9 ++++++---
> include/linux/mm_types.h | 1 +
> kernel/fork.c | 1 +
> mm/memory.c | 30 +++++++++++++++++++++---------
> mm/rmap.c | 1 +
> mm/swapfile.c | 1 +
> 6 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]++;
First thought I come to is that we believe !is_migration_entry(entry) equal
swap entry?
We began supporting HWPOISON.
HWPOISON would be rare event so some less exact swap accouting may
be allowed, I think. Is this enough to jusitfy that?
> + 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--;
ditto
> + 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 +36,7 @@ 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, swap_usage);
> 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-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
> Index: mmotm-2.6.32-Nov2/kernel/fork.c
> ===================================================================
> --- mmotm-2.6.32-Nov2.orig/kernel/fork.c
> +++ mmotm-2.6.32-Nov2/kernel/fork.c
> @@ -454,6 +454,7 @@ static struct mm_struct * mm_init(struct
> mm->nr_ptes = 0;
> set_mm_counter(mm, file_rss, 0);
> set_mm_counter(mm, anon_rss, 0);
> + set_mm_counter(mm, swap_usage, 0);
> spin_lock_init(&mm->page_table_lock);
> mm->free_area_cache = TASK_UNMAPPED_BASE;
> mm->cached_hole_size = ~0UL;
>
> --
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>
That's good.
>From now on, we can chagne scanning of pte to find swap pte
in smaps_pte_rangem, too. :)
--
Kind regards,
Minchan Kim
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