On Mon, 31 Jan 2011, Dave Hansen wrote:
>
> This adds code to explicitly detect and handle
> pmd_trans_huge() pmds. It then passes HPAGE_SIZE units
> in to the smap_pte_entry() function instead of PAGE_SIZE.
>
> This means that using /proc/$pid/smaps now will no longer
> cause THPs to be broken down in to small pages.
>
Nice!
> Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
> ---
>
> linux-2.6.git-dave/fs/proc/task_mmu.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff -puN fs/proc/task_mmu.c~teach-smaps_pte_range-about-thp-pmds fs/proc/task_mmu.c
> --- linux-2.6.git/fs/proc/task_mmu.c~teach-smaps_pte_range-about-thp-pmds 2011-01-31 15:10:55.387856566 -0800
> +++ linux-2.6.git-dave/fs/proc/task_mmu.c 2011-01-31 15:25:12.231239775 -0800
> @@ -1,5 +1,6 @@
> #include <linux/mm.h>
> #include <linux/hugetlb.h>
> +#include <linux/huge_mm.h>
> #include <linux/mount.h>
> #include <linux/seq_file.h>
> #include <linux/highmem.h>
> @@ -385,6 +386,17 @@ static int smaps_pte_range(pmd_t *pmd, u
> pte_t *pte;
> spinlock_t *ptl;
>
> + if (pmd_trans_huge(*pmd)) {
> + if (pmd_trans_splitting(*pmd)) {
> + spin_unlock(&walk->mm->page_table_lock);
> + wait_split_huge_page(vma->anon_vma, pmd);
> + spin_lock(&walk->mm->page_table_lock);
> + goto normal_ptes;
> + }
> + smaps_pte_entry(*(pte_t *)pmd, addr, HPAGE_SIZE, walk);
> + return 0;
> + }
> +normal_ptes:
Small nitpick: the label isn't necessary, just use an else-clause on your
nested conditional.
> split_huge_page_pmd(walk->mm, pmd);
>
> pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
> diff -puN mm/vmscan.c~teach-smaps_pte_range-about-thp-pmds mm/vmscan.c
> diff -puN include/trace/events/vmscan.h~teach-smaps_pte_range-about-thp-pmds include/trace/events/vmscan.h
> diff -puN mm/pagewalk.c~teach-smaps_pte_range-about-thp-pmds mm/pagewalk.c
> diff -puN mm/huge_memory.c~teach-smaps_pte_range-about-thp-pmds mm/huge_memory.c
> diff -puN mm/memory.c~teach-smaps_pte_range-about-thp-pmds mm/memory.c
> diff -puN include/linux/huge_mm.h~teach-smaps_pte_range-about-thp-pmds include/linux/huge_mm.h
> diff -puN mm/internal.h~teach-smaps_pte_range-about-thp-pmds mm/internal.h
> _
What are all these?
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