Re: [PATCH v2] mm: numa_memblks: introduce numa_add_reserved_memblk

Huacai Chen
2025-05-08T01:55:04Z

On Thu, May 8, 2025 at 9:47 AM Yuquan Wang
<wangyuquan1236@phytium.com.cn> wrote:
>
> On Wed, May 07, 2025 at 05:24:36PM +0100, Jonathan Cameron wrote:
> > On Tue, 6 May 2025 14:22:45 +0800
> > Yuquan Wang <wangyuquan1236@phytium.com.cn> wrote:
> >
> > > acpi_parse_cfmws() currently adds empty CFMWS ranges to numa_meminfo
> > > with the expectation that numa_cleanup_meminfo moves them to
> > > numa_reserved_meminfo. There is no need for that indirection when it is
> > > known in advance that these unpopulated ranges are meant for
> > > numa_reserved_meminfo in support of future hotplug / CXL provisioning.
> > >
> > > Introduce and use numa_add_reserved_memblk() to add the empty CFMWS
> > > ranges directly.
> > >
> > > Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
> > This is v2 take 2. There were tags on the previous version (pre longarch
> > change).
> >
> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >
> > (Also Dan Williams).
> >
> > Easiest option when this happens is spin a v3 with a change log to
> > say the loongarch issue is resolved and you picked up tags.
> >
> Hi Jonathan,
>
> Thanks for your tips. Would this v2 version trigger the kernel test
> robot? It seems like only a new version of patch would trigger that.
> I would publish v3 of this patch as soon as possible.

The kernel test robot operates on linux-next, so there's probably no errors now.

Huacai

>
> Yuquan
> >
> > > ---
> > >
> > > Changes in v2 (Thanks to Dan & Alison):
> > > - Use numa_add_reserved_memblk() to replace numa_add_memblk() in acpi_parse_cfmws()
> > > - Add comments to describe the usage of numa_add_reserved_memblk()
> > > - Updating the commit message to clarify the purpose of the patch
> > >
> > > By the way, "LoongArch: Introduce the numa_memblks conversion" is in linux-next.
> > >
> > > drivers/acpi/numa/srat.c | 2 +-
> > > include/linux/numa_memblks.h | 1 +
> > > mm/numa_memblks.c | 22 ++++++++++++++++++++++
> > > 3 files changed, 24 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
> > > index 0a725e46d017..751774f0b4e5 100644
> > > --- a/drivers/acpi/numa/srat.c
> > > +++ b/drivers/acpi/numa/srat.c
> > > @@ -453,7 +453,7 @@ static int __init acpi_parse_cfmws(union acpi_subtable_headers *header,
> > > return -EINVAL;
> > > }
> > >
> > > - if (numa_add_memblk(node, start, end) < 0) {
> > > + if (numa_add_reserved_memblk(node, start, end) < 0) {
> > > /* CXL driver must handle the NUMA_NO_NODE case */
> > > pr_warn("ACPI NUMA: Failed to add memblk for CFMWS node %d [mem %#llx-%#llx]\n",
> > > node, start, end);
> > > diff --git a/include/linux/numa_memblks.h b/include/linux/numa_memblks.h
> > > index dd85613cdd86..991076cba7c5 100644
> > > --- a/include/linux/numa_memblks.h
> > > +++ b/include/linux/numa_memblks.h
> > > @@ -22,6 +22,7 @@ struct numa_meminfo {
> > > };
> > >
> > > int __init numa_add_memblk(int nodeid, u64 start, u64 end);
> > > +int __init numa_add_reserved_memblk(int nid, u64 start, u64 end);
> > > void __init numa_remove_memblk_from(int idx, struct numa_meminfo *mi);
> > >
> > > int __init numa_cleanup_meminfo(struct numa_meminfo *mi);
> > > diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
> > > index ff4054f4334d..541a99c4071a 100644
> > > --- a/mm/numa_memblks.c
> > > +++ b/mm/numa_memblks.c
> > > @@ -200,6 +200,28 @@ int __init numa_add_memblk(int nid, u64 start, u64 end)
> > > return numa_add_memblk_to(nid, start, end, &numa_meminfo);
> > > }
> > >
> > > +/**
> > > + * numa_add_reserved_memblk - Add one numa_memblk to numa_reserved_meminfo
> > > + * @nid: NUMA node ID of the new memblk
> > > + * @start: Start address of the new memblk
> > > + * @end: End address of the new memblk
> > > + *
> > > + * Add a new memblk to the numa_reserved_meminfo.
> > > + *
> > > + * Usage Case: numa_cleanup_meminfo() reconciles all numa_memblk instances
> > > + * against memblock_type information and moves any that intersect reserved
> > > + * ranges to numa_reserved_meminfo. However, when that information is known
> > > + * ahead of time, we use numa_add_reserved_memblk() to add the numa_memblk
> > > + * to numa_reserved_meminfo directly.
> > > + *
> > > + * RETURNS:
> > > + * 0 on success, -errno on failure.
> > > + */
> > > +int __init numa_add_reserved_memblk(int nid, u64 start, u64 end)
> > > +{
> > > + return numa_add_memblk_to(nid, start, end, &numa_reserved_meminfo);
> > > +}
> > > +
> > > /**
> > > * numa_cleanup_meminfo - Cleanup a numa_meminfo
> > > * @mi: numa_meminfo to clean up
> >
>