Re: [PATCH 1/3] Introduce dump_vma

Naoya Horiguchi
2014-08-29T18:51:33Z

On Fri, Aug 29, 2014 at 10:54:17AM -0400, Sasha Levin wrote:
> Introduce a helper to dump information about a VMA, this also
> makes dump_page_flags more generic and re-uses that so the
> output looks very similar to dump_page:
>
> [ 61.903437] vma ffff88070f88be00 start 00007fff25970000 end 00007fff25992000
> [ 61.903437] next ffff88070facd600 prev ffff88070face400 mm ffff88070fade000
> [ 61.903437] prot 8000000000000025 anon_vma ffff88070fa1e200 vm_ops (null)
> [ 61.903437] pgoff 7ffffffdd file (null) private_data (null)
> [ 61.909129] flags: 0x100173(read|write|mayread|maywrite|mayexec|growsdown|account)
>
> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

# checkpatch.pl shows warnings on using printk(KERN_ALERT), but there
# are many other lines using printk in this file, so it should be done
# as a whole in a separate patch.

Thanks,
Naoya Horiguchi

> ---
> include/linux/mmdebug.h | 2 ++
> mm/page_alloc.c | 77 +++++++++++++++++++++++++++++++++++++++++------
> 2 files changed, 70 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
> index 2f348d0..dfb9333 100644
> --- a/include/linux/mmdebug.h
> +++ b/include/linux/mmdebug.h
> @@ -4,10 +4,12 @@
> #include <linux/stringify.h>
>
> struct page;
> +struct vm_area_struct;
>
> extern void dump_page(struct page *page, const char *reason);
> extern void dump_page_badflags(struct page *page, const char *reason,
> unsigned long badflags);
> +void dump_vma(const struct vm_area_struct *vma);
>
> #ifdef CONFIG_DEBUG_VM
> #define VM_BUG_ON(cond) BUG_ON(cond)
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index f86023b..add97b8 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6628,27 +6628,26 @@ static const struct trace_print_flags pageflag_names[] = {
> #endif
> };
>
> -static void dump_page_flags(unsigned long flags)
> +static void dump_flags(unsigned long flags,
> + const struct trace_print_flags *names, int count)
> {
> const char *delim = "";
> unsigned long mask;
> int i;
>
> - BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);
> -
> - printk(KERN_ALERT "page flags: %#lx(", flags);
> + printk(KERN_ALERT "flags: %#lx(", flags);
>
> /* remove zone id */
> flags &= (1UL << NR_PAGEFLAGS) - 1;
>
> - for (i = 0; i < ARRAY_SIZE(pageflag_names) && flags; i++) {
> + for (i = 0; i < count && flags; i++) {
>
> - mask = pageflag_names[i].mask;
> + mask = names[i].mask;
> if ((flags & mask) != mask)
> continue;
>
> flags &= ~mask;
> - printk("%s%s", delim, pageflag_names[i].name);
> + printk("%s%s", delim, names[i].name);
> delim = "|";
> }
>
> @@ -6666,12 +6665,14 @@ void dump_page_badflags(struct page *page, const char *reason,
> "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
> page, atomic_read(&page->_count), page_mapcount(page),
> page->mapping, page->index);
> - dump_page_flags(page->flags);
> + BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS);
> + dump_flags(page->flags, pageflag_names, ARRAY_SIZE(pageflag_names));
> if (reason)
> pr_alert("page dumped because: %s\n", reason);
> if (page->flags & badflags) {
> pr_alert("bad because of flags:\n");
> - dump_page_flags(page->flags & badflags);
> + dump_flags(page->flags & badflags,
> + pageflag_names, ARRAY_SIZE(pageflag_names));
> }
> mem_cgroup_print_bad_page(page);
> }
> @@ -6681,3 +6682,61 @@ void dump_page(struct page *page, const char *reason)
> dump_page_badflags(page, reason, 0);
> }
> EXPORT_SYMBOL(dump_page);
> +
> +static const struct trace_print_flags vmaflags_names[] = {
> + {VM_READ, "read" },
> + {VM_WRITE, "write" },
> + {VM_EXEC, "exec" },
> + {VM_SHARED, "shared" },
> + {VM_MAYREAD, "mayread" },
> + {VM_MAYWRITE, "maywrite" },
> + {VM_MAYEXEC, "mayexec" },
> + {VM_MAYSHARE, "mayshare" },
> + {VM_GROWSDOWN, "growsdown" },
> + {VM_PFNMAP, "pfnmap" },
> + {VM_DENYWRITE, "denywrite" },
> + {VM_LOCKED, "locked" },
> + {VM_IO, "io" },
> + {VM_SEQ_READ, "seqread" },
> + {VM_RAND_READ, "randread" },
> + {VM_DONTCOPY, "dontcopy" },
> + {VM_DONTEXPAND, "dontexpand" },
> + {VM_ACCOUNT, "account" },
> + {VM_NORESERVE, "noreserve" },
> + {VM_HUGETLB, "hugetlb" },
> + {VM_NONLINEAR, "nonlinear" },
> +#if defined(CONFIG_X86)
> + {VM_PAT, "pat" },
> +#elif defined(CONFIG_PPC)
> + {VM_SAO, "sao" },
> +#elif defined(CONFIG_PARISC) || defined(CONFIG_METAG) || defined(CONFIG_IA64)
> + {VM_GROWSUP, "growsup" },
> +#elif !defined(CONFIG_MMU)
> + {VM_MAPPED_COPY, "mappedcopy" },
> +#else
> + {VM_ARCH_1, "arch_1" },
> +#endif
> + {VM_DONTDUMP, "dontdump" },
> +#ifdef CONFIG_MEM_SOFT_DIRTY
> + {VM_SOFTDIRTY, "softdirty" },
> +#endif
> + {VM_MIXEDMAP, "mixedmap" },
> + {VM_HUGEPAGE, "hugepage" },
> + {VM_NOHUGEPAGE, "nohugepage" },
> + {VM_MERGEABLE, "mergeable" },
> +};
> +
> +void dump_vma(const struct vm_area_struct *vma)
> +{
> + printk(KERN_ALERT
> + "vma %p start %p end %p\n"
> + "next %p prev %p mm %p\n"
> + "prot %lx anon_vma %p vm_ops %p\n"
> + "pgoff %lx file %p private_data %p\n",
> + vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
> + vma->vm_prev, vma->vm_mm, vma->vm_page_prot.pgprot,
> + vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
> + vma->vm_file, vma->vm_private_data);
> + dump_flags(vma->vm_flags, vmaflags_names, ARRAY_SIZE(vmaflags_names));
> +}
> +EXPORT_SYMBOL(dump_vma);
> --
> 1.7.10.4
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: email@kvack.org
>