On Tue, 8 Dec 2015 11:39:50 -0800
Yang Shi <yang.shi@xxxxxxxxxx> wrote:
> For slow version, just add trace point for raw __get_user_pages since all
> slow variants call it to do the real work finally.
>
> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxx>
> ---
> mm/gup.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index deafa2c..44f05c9 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -18,6 +18,9 @@
>
> #include "internal.h"
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/gup.h>
> +
> static struct page *no_page_table(struct vm_area_struct *vma,
> unsigned int flags)
> {
> @@ -462,6 +465,8 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
> if (!nr_pages)
> return 0;
>
> + trace_gup_get_user_pages(start, nr_pages);
> +
> VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
>
> /*
> @@ -599,6 +604,7 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
> if (!(vm_flags & vma->vm_flags))
> return -EFAULT;
>
> + trace_gup_fixup_user_fault(address);
> ret = handle_mm_fault(mm, vma, address, fault_flags);
> if (ret & VM_FAULT_ERROR) {
> if (ret & VM_FAULT_OOM)
> @@ -1340,6 +1346,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
> start, len)))
> return 0;
>
> + trace_gup_get_user_pages_fast(start, (unsigned long) nr_pages);
typecast shouldn't be needed. But I'm wondering, it would save space in
the ring buffer if we used unsigend int instead of long. Will nr_pages
ever be bigger than 4 billion?
-- Steve
> +
> /*
> * Disable interrupts. We use the nested form as we can already have
> * interrupts disabled by get_futex_key.
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