Hello,
On (06/09/15 23:43), Minchan Kim wrote:
[..]
> @@ -446,6 +446,7 @@ struct mem_size_stats {
> unsigned long anonymous_thp;
> unsigned long swap;
> u64 pss;
> + u64 swap_pss;
> };
>
> static void smaps_account(struct mem_size_stats *mss, struct page *page,
> @@ -492,9 +493,20 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
> } else if (is_swap_pte(*pte)) {
> swp_entry_t swpent = pte_to_swp_entry(*pte);
>
> - if (!non_swap_entry(swpent))
> + if (!non_swap_entry(swpent)) {
> + int mapcount;
> +
> mss->swap += PAGE_SIZE;
> - else if (is_migration_entry(swpent))
> + mapcount = swp_swapcount(swpent);
I think this will break swapless builds (CONFIG_SWAP=n builds).
-ss
> + if (mapcount >= 2) {
> + u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
> +
> + do_div(pss_delta, mapcount);
> + mss->swap_pss += pss_delta;
> + } else {
> + mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
> + }
> + } else if (is_migration_entry(swpent))
> page = migration_entry_to_page(swpent);
> }
>
> @@ -640,6 +652,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
> "Anonymous: %8lu kB\n"
> "AnonHugePages: %8lu kB\n"
> "Swap: %8lu kB\n"
> + "SwapPss: %8lu kB\n"
> "KernelPageSize: %8lu kB\n"
> "MMUPageSize: %8lu kB\n"
> "Locked: %8lu kB\n",
> @@ -654,6 +667,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
> mss.anonymous >> 10,
> mss.anonymous_thp >> 10,
> mss.swap >> 10,
> + (unsigned long)(mss.swap_pss >> (10 + PSS_SHIFT)),
> vma_kernel_pagesize(vma) >> 10,
> vma_mmu_pagesize(vma) >> 10,
> (vma->vm_flags & VM_LOCKED) ?
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 9a7adfb..402a24b 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -432,6 +432,7 @@ extern unsigned int count_swap_pages(int, int);
> extern sector_t map_swap_page(struct page *, struct block_device **);
> extern sector_t swapdev_block(int, pgoff_t);
> extern int page_swapcount(struct page *);
> +extern int swp_swapcount(swp_entry_t entry);
> extern struct swap_info_struct *page_swap_info(struct page *);
> extern int reuse_swap_page(struct page *);
> extern int try_to_free_swap(struct page *);
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index a7e7210..7a6bd1e 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -875,6 +875,48 @@ int page_swapcount(struct page *page)
> }
>
> /*
> + * How many references to @entry are currently swapped out?
> + * This considers COUNT_CONTINUED so it returns exact answer.
> + */
> +int swp_swapcount(swp_entry_t entry)
> +{
> + int count, tmp_count, n;
> + struct swap_info_struct *p;
> + struct page *page;
> + pgoff_t offset;
> + unsigned char *map;
> +
> + p = swap_info_get(entry);
> + if (!p)
> + return 0;
> +
> + count = swap_count(p->swap_map[swp_offset(entry)]);
> + if (!(count & COUNT_CONTINUED))
> + goto out;
> +
> + count &= ~COUNT_CONTINUED;
> + n = SWAP_MAP_MAX + 1;
> +
> + offset = swp_offset(entry);
> + page = vmalloc_to_page(p->swap_map + offset);
> + offset &= ~PAGE_MASK;
> + VM_BUG_ON(page_private(page) != SWP_CONTINUED);
> +
> + do {
> + page = list_entry(page->lru.next, struct page, lru);
> + map = kmap_atomic(page) + offset;
> + tmp_count = *map;
> + kunmap_atomic(map);
> +
> + count += (tmp_count & ~COUNT_CONTINUED) * n;
> + n *= (SWAP_CONT_MAX + 1);
> + } while (tmp_count & COUNT_CONTINUED);
> +out:
> + spin_unlock(&p->lock);
> + return count;
> +}
> +
> +/*
> * We can write to an anon page without COW if there are no other references
> * to it. And as a side-effect, free up its swap: because the old content
> * on disk will never be read, and seeking back there to write new content
--
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