On Thu 30 Nov 2017, 15:49, Michal Hocko wrote:
> On Thu 23-11-17 11:14:52, Andrea Reale wrote:
> > Adding a "remove" sysfs handle that can be used to trigger
> > memory hotremove manually, exactly simmetrically with
> > what happens with the "probe" device for hot-add.
> >
> > This is usueful for architecture that do not rely on
> > ACPI for memory hot-remove.
>
> As already said elsewhere, this really has to check the online status of
> the range and fail some is still online.
>
This is actually still done in remove_memory() (patch 2/5) with
walk_memory_range. We just return an error rather than BUGing().
Or are you referring to something else?
> > Signed-off-by: Andrea Reale <ar@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Maciej Bielski <m.bielski@xxxxxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/base/memory.c | 34 +++++++++++++++++++++++++++++++++-
> > 1 file changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> > index 1d60b58..8ccb67c 100644
> > --- a/drivers/base/memory.c
> > +++ b/drivers/base/memory.c
> > @@ -530,7 +530,36 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
> > }
> >
> > static DEVICE_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
> > -#endif
> > +
> > +#ifdef CONFIG_MEMORY_HOTREMOVE
> > +static ssize_t
> > +memory_remove_store(struct device *dev,
> > + struct device_attribute *attr, const char *buf, size_t count)
> > +{
> > + u64 phys_addr;
> > + int nid, ret;
> > + unsigned long pages_per_block = PAGES_PER_SECTION * sections_per_block;
> > +
> > + ret = kstrtoull(buf, 0, &phys_addr);
> > + if (ret)
> > + return ret;
> > +
> > + if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
> > + return -EINVAL;
> > +
> > + nid = memory_add_physaddr_to_nid(phys_addr);
> > + ret = lock_device_hotplug_sysfs();
> > + if (ret)
> > + return ret;
> > +
> > + remove_memory(nid, phys_addr,
> > + MIN_MEMORY_BLOCK_SIZE * sections_per_block);
> > + unlock_device_hotplug();
> > + return count;
> > +}
> > +static DEVICE_ATTR(remove, S_IWUSR, NULL, memory_remove_store);
> > +#endif /* CONFIG_MEMORY_HOTREMOVE */
> > +#endif /* CONFIG_ARCH_MEMORY_PROBE */
> >
> > #ifdef CONFIG_MEMORY_FAILURE
> > /*
> > @@ -790,6 +819,9 @@ bool is_memblock_offlined(struct memory_block *mem)
> > static struct attribute *memory_root_attrs[] = {
> > #ifdef CONFIG_ARCH_MEMORY_PROBE
> > &dev_attr_probe.attr,
> > +#ifdef CONFIG_MEMORY_HOTREMOVE
> > + &dev_attr_remove.attr,
> > +#endif
> > #endif
> >
> > #ifdef CONFIG_MEMORY_FAILURE
> > --
> > 2.7.4
Thanks,
Andrea
>
> --
> Michal Hocko
> SUSE Labs
>
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