On Mon, Mar 02, 2020 at 05:22:03PM -0800, Matthew Wilcox wrote:
> On Mon, Mar 02, 2020 at 04:26:38PM -0800, Minchan Kim wrote:
> > @@ -1196,6 +1196,7 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
> > struct vm_area_struct *vma = NULL;
> > int locked = 0;
> > long ret = 0;
> > + bool tried = false;
>
> How about ...
>
> int *lockedp = &locked;
>
> >
> > end = start + len;
> >
> > @@ -1226,14 +1227,18 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
> > * double checks the vma flags, so that it won't mlock pages
> > * if the vma was already munlocked.
> > */
> > - ret = populate_vma_page_range(vma, nstart, nend, &locked);
> > + ret = populate_vma_page_range(vma, nstart, nend,
> > + tried ? NULL : &locked);
>
> ret = populate_vma_page_range(vma, nstart, nend, lockedp);
>
> > if (ret < 0) {
> > if (ignore_errors) {
> > ret = 0;
> > continue; /* continue at next VMA */
> > }
> > break;
> > - }
> > + } else if (ret == 0)
> > + tried = true;
> > + else
> > + tried = false;
>
> } else if (ret == 0)
> lockedp = NULL;
>
> Maybe there's a better name than lockedp.
Thanks for the review, Matthew.
It changes the behavior from mine in that it never set lockedp as "non-NULL"
since it had retried so that we lose fault retrying optimization for
successive addresses
I understand the code is not pretty there so that hard to follow it but
I am not sure the your suggestion makes it better.
