On Wed, Aug 29, 2018 at 10:11:53AM +1000, Dave Chinner wrote:
> > +++ b/Documentation/sysctl/fs.txt
> > @@ -63,19 +63,26 @@ struct {
> > int nr_unused;
> > int age_limit; /* age in seconds */
> > int want_pages; /* pages requested by system */
> > - int dummy[2];
> > + int nr_negative; /* # of unused negative dentries */
> > + int dummy;
> > } dentry_stat = {0, 0, 45, 0,};
>
> That's not a backwards compatible ABI change. Those dummy fields
> used to represent some metric we no longer calculate, and there are
> probably still monitoring apps out there that think they still have
> the old meaning. i.e. they are still visible to userspace:
I believe you are incorrect. dentry_stat was introduced in 2.1.60 with
this hunk:
+struct {
+ int nr_dentry;
+ int nr_unused;
+ int age_limit; /* age in seconds */
+ int want_pages; /* pages requested by system */
+ int dummy[2];
+} dentry_stat = {0, 0, 45, 0,};
+
Looking through the rest of the dentry_stat changes in the 2.1.60 release,
it's not replacing anything, it's adding new information.
