From 08fba69986e20c1c9e5fe2e6064d146cc4f42480 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 6 Jan 2009 14:38:53 -0800 Subject: [PATCH] mm: report the pagesize backing a VMA in /proc/pid/smaps It is useful to verify a hugepage-aware application is using the expected pagesizes for its memory regions. This patch creates an entry called KernelPageSize in /proc/pid/smaps that is the size of page used by the kernel to back a VMA. The entry is not called PageSize as it is possible the MMU uses a different size. This extension should not break any sensible parser that skips lines containing unrecognised information. Signed-off-by: Mel Gorman Acked-by: "KOSAKI Motohiro" Cc: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_mmu.c | 6 ++++-- include/linux/hugetlb.h | 3 +++ mm/hugetlb.c | 16 ++++++++++++++++ 3 files changed, 23 insertions(+), 2 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 3a8bdd7f5756..41ef5f23e779 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -396,7 +396,8 @@ static int show_smap(struct seq_file *m, void *v) "Private_Clean: %8lu kB\n" "Private_Dirty: %8lu kB\n" "Referenced: %8lu kB\n" - "Swap: %8lu kB\n", + "Swap: %8lu kB\n" + "KernelPageSize: %8lu kB\n", (vma->vm_end - vma->vm_start) >> 10, mss.resident >> 10, (unsigned long)(mss.pss >> (10 + PSS_SHIFT)), @@ -405,7 +406,8 @@ static int show_smap(struct seq_file *m, void *v) mss.private_clean >> 10, mss.private_dirty >> 10, mss.referenced >> 10, - mss.swap >> 10); + mss.swap >> 10, + vma_kernel_pagesize(vma) >> 10); if (m->count < m->size) /* vma is copied successfully */ m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0; diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index e1c8afc002c0..648e1e25979e 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -233,6 +233,8 @@ static inline unsigned long huge_page_size(struct hstate *h) return (unsigned long)PAGE_SIZE << h->order; } +extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma); + static inline unsigned long huge_page_mask(struct hstate *h) { return h->mask; @@ -273,6 +275,7 @@ struct hstate {}; #define hstate_inode(i) NULL #define huge_page_size(h) PAGE_SIZE #define huge_page_mask(h) PAGE_MASK +#define vma_kernel_pagesize(v) PAGE_SIZE #define huge_page_order(h) 0 #define huge_page_shift(h) PAGE_SHIFT static inline unsigned int pages_per_huge_page(struct hstate *h) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6058b53dcb89..5cb8bc7c80f7 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -219,6 +219,22 @@ static pgoff_t vma_hugecache_offset(struct hstate *h, (vma->vm_pgoff >> huge_page_order(h)); } +/* + * Return the size of the pages allocated when backing a VMA. In the majority + * cases this will be same size as used by the page table entries. + */ +unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) +{ + struct hstate *hstate; + + if (!is_vm_hugetlb_page(vma)) + return PAGE_SIZE; + + hstate = hstate_vma(vma); + + return 1UL << (hstate->order + PAGE_SHIFT); +} + /* * Flags for MAP_PRIVATE reservations. These are stored in the bottom * bits of the reservation map pointer, which are always clear due to -- 2.20.1