Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved
On 07/28/20 at 05:15pm, Mike Rapoport wrote:
> On Tue, Jul 28, 2020 at 07:02:54PM +0800, Baoquan He wrote:
> > On 07/28/20 at 08:11am, Mike Rapoport wrote:
> > > From: Mike Rapoport
> > >
> > > numa_clear_kernel_node_hotplug() function first traverses numa_meminfo
> > > regions to set node ID in memblock.reserved and than traverses
> > > memblock.reserved to update reserved_nodemask to include node IDs that
> > > were
> > > set in the first loop.
> > >
> > > Remove redundant traversal over memblock.reserved and update
> > > reserved_nodemask while iterating over numa_meminfo.
> > >
> > > Signed-off-by: Mike Rapoport
> > > ---
> > > arch/x86/mm/numa.c | 26 ++
> > > 1 file changed, 10 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> > > index 8ee952038c80..4078abd33938 100644
> > > --- a/arch/x86/mm/numa.c
> > > +++ b/arch/x86/mm/numa.c
> > > @@ -498,31 +498,25 @@ static void __init
> > > numa_clear_kernel_node_hotplug(void)
> > >* and use those ranges to set the nid in memblock.reserved.
> > >* This will split up the memblock regions along node
> > >* boundaries and will set the node IDs as well.
> > > + *
> > > + * The nid will also be set in reserved_nodemask which is later
> > > + * used to clear MEMBLOCK_HOTPLUG flag.
> > > + *
> > > + * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
> > > + * numa_meminfo might not include all memblock.reserved
> > > + * memory ranges, because quirks such as trim_snb_memory()
> > > + * reserve specific pages for Sandy Bridge graphics.
> > > + * These ranges will remain with nid == MAX_NUMNODES. ]
> > >*/
> > > for (i = 0; i < numa_meminfo.nr_blks; i++) {
> > > struct numa_memblk *mb = numa_meminfo.blk + i;
> > > int ret;
> > >
> > > ret = memblock_set_node(mb->start, mb->end - mb->start,
> > > , mb->nid);
> > > + node_set(mb->nid, reserved_nodemask);
> >
> > Really? This will set all node id into reserved_nodemask. But in the
> > current code, it's setting nid into memblock reserved region which
> > interleaves with numa_memoinfo, then get those nid and set it in
> > reserved_nodemask. This is so different, with my understanding. Please
> > correct me if I am wrong.
>
> You are right, I've missed the intersections of numa_meminfo with
> memblock.reserved.
>
> x86 interaction with membock is so, hmm, interesting...
Yeah, numa_clear_kernel_node_hotplug() intends to find out any memory node
which has reserved memory, then make it as unmovable. Setting all node
id into reserved_nodemask will break the use case of hot removing hotpluggable
boot memory after system bootup.
Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved
On Tue, Jul 28, 2020 at 07:02:54PM +0800, Baoquan He wrote:
> On 07/28/20 at 08:11am, Mike Rapoport wrote:
> > From: Mike Rapoport
> >
> > numa_clear_kernel_node_hotplug() function first traverses numa_meminfo
> > regions to set node ID in memblock.reserved and than traverses
> > memblock.reserved to update reserved_nodemask to include node IDs that were
> > set in the first loop.
> >
> > Remove redundant traversal over memblock.reserved and update
> > reserved_nodemask while iterating over numa_meminfo.
> >
> > Signed-off-by: Mike Rapoport
> > ---
> > arch/x86/mm/numa.c | 26 ++
> > 1 file changed, 10 insertions(+), 16 deletions(-)
> >
> > diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> > index 8ee952038c80..4078abd33938 100644
> > --- a/arch/x86/mm/numa.c
> > +++ b/arch/x86/mm/numa.c
> > @@ -498,31 +498,25 @@ static void __init
> > numa_clear_kernel_node_hotplug(void)
> > * and use those ranges to set the nid in memblock.reserved.
> > * This will split up the memblock regions along node
> > * boundaries and will set the node IDs as well.
> > +*
> > +* The nid will also be set in reserved_nodemask which is later
> > +* used to clear MEMBLOCK_HOTPLUG flag.
> > +*
> > +* [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
> > +* numa_meminfo might not include all memblock.reserved
> > +* memory ranges, because quirks such as trim_snb_memory()
> > +* reserve specific pages for Sandy Bridge graphics.
> > +* These ranges will remain with nid == MAX_NUMNODES. ]
> > */
> > for (i = 0; i < numa_meminfo.nr_blks; i++) {
> > struct numa_memblk *mb = numa_meminfo.blk + i;
> > int ret;
> >
> > ret = memblock_set_node(mb->start, mb->end - mb->start,
> > , mb->nid);
> > + node_set(mb->nid, reserved_nodemask);
>
> Really? This will set all node id into reserved_nodemask. But in the
> current code, it's setting nid into memblock reserved region which
> interleaves with numa_memoinfo, then get those nid and set it in
> reserved_nodemask. This is so different, with my understanding. Please
> correct me if I am wrong.
You are right, I've missed the intersections of numa_meminfo with
memblock.reserved.
x86 interaction with membock is so, hmm, interesting...
> Thanks
> Baoquan
>
> > WARN_ON_ONCE(ret);
> > }
> >
> > - /*
> > -* Now go over all reserved memblock regions, to construct a
> > -* node mask of all kernel reserved memory areas.
> > -*
> > -* [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
> > -* numa_meminfo might not include all memblock.reserved
> > -* memory ranges, because quirks such as trim_snb_memory()
> > -* reserve specific pages for Sandy Bridge graphics. ]
> > -*/
> > - for_each_memblock(reserved, mb_region) {
> > - int nid = memblock_get_region_node(mb_region);
> > -
> > - if (nid != MAX_NUMNODES)
> > - node_set(nid, reserved_nodemask);
> > - }
> > -
> > /*
> > * Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
> > * belonging to the reserved node mask.
> > --
> > 2.26.2
> >
> >
>
--
Sincerely yours,
Mike.
Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved
* Mike Rapoport wrote: > On Tue, Jul 28, 2020 at 12:44:40PM +0200, Ingo Molnar wrote: > > > > * Mike Rapoport wrote: > > > > > From: Mike Rapoport > > > > > > numa_clear_kernel_node_hotplug() function first traverses numa_meminfo > > > regions to set node ID in memblock.reserved and than traverses > > > memblock.reserved to update reserved_nodemask to include node IDs that > > > were > > > set in the first loop. > > > > > > Remove redundant traversal over memblock.reserved and update > > > reserved_nodemask while iterating over numa_meminfo. > > > > > > Signed-off-by: Mike Rapoport > > > --- > > > arch/x86/mm/numa.c | 26 ++ > > > 1 file changed, 10 insertions(+), 16 deletions(-) > > > > I suspect you'd like to carry this in the -mm tree? > > Yes. > > > Acked-by: Ingo Molnar > > Thanks! Assuming it is correct and works. :-) Thanks, Ingo
Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved
On 07/28/20 at 08:11am, Mike Rapoport wrote:
> From: Mike Rapoport
>
> numa_clear_kernel_node_hotplug() function first traverses numa_meminfo
> regions to set node ID in memblock.reserved and than traverses
> memblock.reserved to update reserved_nodemask to include node IDs that were
> set in the first loop.
>
> Remove redundant traversal over memblock.reserved and update
> reserved_nodemask while iterating over numa_meminfo.
>
> Signed-off-by: Mike Rapoport
> ---
> arch/x86/mm/numa.c | 26 ++
> 1 file changed, 10 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 8ee952038c80..4078abd33938 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -498,31 +498,25 @@ static void __init numa_clear_kernel_node_hotplug(void)
>* and use those ranges to set the nid in memblock.reserved.
>* This will split up the memblock regions along node
>* boundaries and will set the node IDs as well.
> + *
> + * The nid will also be set in reserved_nodemask which is later
> + * used to clear MEMBLOCK_HOTPLUG flag.
> + *
> + * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
> + * numa_meminfo might not include all memblock.reserved
> + * memory ranges, because quirks such as trim_snb_memory()
> + * reserve specific pages for Sandy Bridge graphics.
> + * These ranges will remain with nid == MAX_NUMNODES. ]
>*/
> for (i = 0; i < numa_meminfo.nr_blks; i++) {
> struct numa_memblk *mb = numa_meminfo.blk + i;
> int ret;
>
> ret = memblock_set_node(mb->start, mb->end - mb->start,
> , mb->nid);
> + node_set(mb->nid, reserved_nodemask);
Really? This will set all node id into reserved_nodemask. But in the
current code, it's setting nid into memblock reserved region which
interleaves with numa_memoinfo, then get those nid and set it in
reserved_nodemask. This is so different, with my understanding. Please
correct me if I am wrong.
Thanks
Baoquan
> WARN_ON_ONCE(ret);
> }
>
> - /*
> - * Now go over all reserved memblock regions, to construct a
> - * node mask of all kernel reserved memory areas.
> - *
> - * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
> - * numa_meminfo might not include all memblock.reserved
> - * memory ranges, because quirks such as trim_snb_memory()
> - * reserve specific pages for Sandy Bridge graphics. ]
> - */
> - for_each_memblock(reserved, mb_region) {
> - int nid = memblock_get_region_node(mb_region);
> -
> - if (nid != MAX_NUMNODES)
> - node_set(nid, reserved_nodemask);
> - }
> -
> /*
>* Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
>* belonging to the reserved node mask.
> --
> 2.26.2
>
>
Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved
On Tue, Jul 28, 2020 at 12:44:40PM +0200, Ingo Molnar wrote: > > * Mike Rapoport wrote: > > > From: Mike Rapoport > > > > numa_clear_kernel_node_hotplug() function first traverses numa_meminfo > > regions to set node ID in memblock.reserved and than traverses > > memblock.reserved to update reserved_nodemask to include node IDs that were > > set in the first loop. > > > > Remove redundant traversal over memblock.reserved and update > > reserved_nodemask while iterating over numa_meminfo. > > > > Signed-off-by: Mike Rapoport > > --- > > arch/x86/mm/numa.c | 26 ++ > > 1 file changed, 10 insertions(+), 16 deletions(-) > > I suspect you'd like to carry this in the -mm tree? Yes. > Acked-by: Ingo Molnar Thanks! > Thanks, > > Ingo -- Sincerely yours, Mike.
Re: [PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved
* Mike Rapoport wrote: > From: Mike Rapoport > > numa_clear_kernel_node_hotplug() function first traverses numa_meminfo > regions to set node ID in memblock.reserved and than traverses > memblock.reserved to update reserved_nodemask to include node IDs that were > set in the first loop. > > Remove redundant traversal over memblock.reserved and update > reserved_nodemask while iterating over numa_meminfo. > > Signed-off-by: Mike Rapoport > --- > arch/x86/mm/numa.c | 26 ++ > 1 file changed, 10 insertions(+), 16 deletions(-) I suspect you'd like to carry this in the -mm tree? Acked-by: Ingo Molnar Thanks, Ingo
