Re: [PATCH v4 46/66] perf: Use VMA iterator

[Vlastimil Babka]

On 12/1/21 15:30, Liam Howlett wrote:
> From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
> 
> The VMA iterator is faster than the linked list and removing the linked
> list will shrink the vm_area_struct.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  kernel/events/core.c    | 3 ++-
>  kernel/events/uprobes.c | 9 ++++++---
>  2 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 523106a506ee..d839ba79fe5c 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10218,8 +10218,9 @@ static void perf_addr_filter_apply(struct perf_addr_filter *filter,
>  				   struct perf_addr_filter_range *fr)
>  {
>  	struct vm_area_struct *vma;
> +	VMA_ITERATOR(vmi, mm, 0);
>  
> -	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> +	for_each_vma(vmi, vma) {
>  		if (!vma->vm_file)
>  			continue;
>  
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index 6357c3580d07..5dee6c41f36d 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -356,9 +356,10 @@ static bool valid_ref_ctr_vma(struct uprobe *uprobe,
>  static struct vm_area_struct *
>  find_ref_ctr_vma(struct uprobe *uprobe, struct mm_struct *mm)
>  {
> +	VMA_ITERATOR(vmi, mm, 0);
>  	struct vm_area_struct *tmp;
>  
> -	for (tmp = mm->mmap; tmp; tmp = tmp->vm_next)
> +	for_each_vma(vmi, tmp)
>  		if (valid_ref_ctr_vma(uprobe, tmp))
>  			return tmp;
>  
> @@ -1237,11 +1238,12 @@ int uprobe_apply(struct inode *inode, loff_t offset,
>  
>  static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
>  {
> +	VMA_ITERATOR(vmi, mm, 0);
>  	struct vm_area_struct *vma;
>  	int err = 0;
>  
>  	mmap_read_lock(mm);
> -	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> +	for_each_vma(vmi, vma) {
>  		unsigned long vaddr;
>  		loff_t offset;
>  
> @@ -1989,9 +1991,10 @@ bool uprobe_deny_signal(void)
>  
>  static void mmf_recalc_uprobes(struct mm_struct *mm)
>  {
> +	VMA_ITERATOR(vmi, mm, 0);
>  	struct vm_area_struct *vma;
>  
> -	for (vma = mm->mmap; vma; vma = vma->vm_next) {
> +	for_each_vma(vmi, vma) {
>  		if (!valid_vma(vma, false))
>  			continue;
>  		/*