Re: [PATCH v2] mm:vmscan: shrink skip folio mapped by an exiting task

[zhiguojiang]

在 2024/2/2 17:22, Andrew Morton 写道:
> On Wed, 31 Jan 2024 21:12:44 +0800 Zhiguo Jiang <justinjiang@xxxxxxxx> wrote:
>
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -840,6 +840,13 @@ static bool folio_referenced_one(struct folio *folio,
> >   	int referenced = 0;
> >   	unsigned long start = address, ptes = 0;
> >   
> > +	/* Skip this folio if it's mapped by an exiting task */
> > +	if (unlikely(!atomic_read(&vma->vm_mm->mm_users)) ||
> > +		unlikely(test_bit(MMF_OOM_SKIP, &vma->vm_mm->flags))) {
> > +		pra->referenced = -1;
> > +		return false;
> > +	}
> The code comment explains what the code does.  This is, as usual,
> pretty obvious from reading the code!
>
> A better comment is one which explains *why* the code is doing what it
> does.
Yes, thank you for your recognition, and I also appreciate Matthew Wilcox's
professional and patient guidance in patch v1. I will study this 
seriously in the
future.

Best Regards.