On Tue, Dec 22, 2015 at 02:19:20PM +0300, Denis Kirjanov wrote: > On 12/22/15, David Gibson <[email protected]> wrote: > > This patch adds a special file in /sys/kernel/mm which can be used to view > > the current size of the hash page table (as a bit shift) and to trigger > > a resize of the hash table on PAPR guests. > > > > Logically this would make more sense as a debugfs file, but that doesn't > > see to provide an obvious way to have a "store" function that has an effect > > other than updating a variable. > > > > Signed-off-by: David Gibson <[email protected]> > > --- > > arch/powerpc/platforms/pseries/lpar.c | 41 > > +++++++++++++++++++++++++++++++++++ > > 1 file changed, 41 insertions(+) > > > > diff --git a/arch/powerpc/platforms/pseries/lpar.c > > b/arch/powerpc/platforms/pseries/lpar.c > > index aadb242..2759767 100644 > > --- a/arch/powerpc/platforms/pseries/lpar.c > > +++ b/arch/powerpc/platforms/pseries/lpar.c > > @@ -903,3 +903,44 @@ int pSeries_lpar_resize_hpt(unsigned long shift) > > > > return 0; > > } > > + > > +static ssize_t ppc64_pft_size_show(struct kobject *kobj, > > + struct kobj_attribute *attr, char *buf) > > +{ > > + return sprintf(buf, "%llu\n", (unsigned long long)ppc64_pft_size); > > +} > > + > > +static ssize_t ppc64_pft_size_store(struct kobject *kobj, > > + struct kobj_attribute *attr, > > + const char *buf, size_t count) > > +{ > > + unsigned long new_shift; > > + int rc; > > + > > + pr_err("lpar: ppc64_pft_size_store() count=%zd\n", count); > Why pr_err?
Uh.. good question. That's a not particularly useful debug comment I
should just remove anyway.
> > +
> > + if (kstrtoul(buf, 0, &new_shift))
> > + return -EINVAL;
> > +
> > + rc = pSeries_lpar_resize_hpt(new_shift);
> > + if (rc < 0)
> > + return rc;
> > +
> > + return count;
> > +}
> > +
> > +static struct kobj_attribute ppc64_pft_size_attr =
> > + __ATTR(ppc64_pft_size, 0600, ppc64_pft_size_show, ppc64_pft_size_store);
> > +
> > +static int __init pseries_lpar_sysfs(void)
> > +{
> > + int rc;
> > +
> > + rc = sysfs_create_file(mm_kobj, &ppc64_pft_size_attr.attr);
> > + if (rc)
> > + pr_err("lpar: unable to create ppc64_pft_size sysfs file
> > (%d)\n",
> > + rc);
> > +
> > + return 0;
> I think that we need to return rc value, right?
No. Failing to register this sysfs file shouldn't cause the boot to fail.
> > +}
> > +machine_device_initcall(pseries, pseries_lpar_sysfs);
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > [email protected]
> > https://lists.ozlabs.org/listinfo/linuxppc-dev
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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