Re: [PATCH 05/17] arch, mm: pull out allocation of NODE_DATA to generic code

Mike Rapoport
2024-07-19T15:37:59Z

On Fri, Jul 19, 2024 at 05:07:35PM +0200, David Hildenbrand wrote:
> > > > - * Allocate node data. Try node-local memory and then any node.
> > > > - * Never allocate in DMA zone.
> > > > - */
> > > > - nd_pa = memblock_phys_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
> > > > - if (!nd_pa) {
> > > > - pr_err("Cannot find %zu bytes in any node (initial node: %d)\n",
> > > > - nd_size, nid);
> > > > - return;
> > > > - }
> > > > - nd = __va(nd_pa);
> > > > -
> > > > - /* report and initialize */
> > > > - printk(KERN_INFO "NODE_DATA(%d) allocated [mem %#010Lx-%#010Lx]\n", nid,
> > > > - nd_pa, nd_pa + nd_size - 1);
> > > > - tnid = early_pfn_to_nid(nd_pa >> PAGE_SHIFT);
> > > > - if (tnid != nid)
> > > > - printk(KERN_INFO " NODE_DATA(%d) on node %d\n", nid, tnid);
> > > > -
> > > > - node_data[nid] = nd;
> > > > - memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
> > > > -
> > > > - node_set_online(nid);
> > > > -}
> > > > -
> > > > /**
> > > > * numa_cleanup_meminfo - Cleanup a numa_meminfo
> > > > * @mi: numa_meminfo to clean up
> > > > @@ -571,6 +538,7 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
> > > > continue;
> > > > alloc_node_data(nid);
> > > > + node_set_online(nid);
> > > > }
> > >
> > > I can spot that we only remove a single node_set_online() call from x86.
> > >
> > > What about all the other architectures? Will there be any change in behavior
> > > for them? Or do we simply set the nodes online later once more?
> >
> > On x86 node_set_online() was a part of alloc_node_data() and I moved it
> > outside so it's called right after alloc_node_data(). On other
> > architectures the allocation didn't include that call, so there should be
> > no difference there.
>
> But won't their arch code try setting the nodes online at a later stage?
>
> And I think, some architectures only set nodes online conditionally
> (see most other node_set_online() calls).
>
> Sorry if I'm confused here, but with now unconditional node_set_online(), won't
> we change the behavior of other architectures?

The generic alloc_node_data() does not set the node online:

+/* Allocate NODE_DATA for a node on the local memory */
+void __init alloc_node_data(int nid)
+{
+ const size_t nd_size = roundup(sizeof(pg_data_t), PAGE_SIZE);
+ u64 nd_pa;
+ void *nd;
+ int tnid;
+
+ /* Allocate node data. Try node-local memory and then any node. */
+ nd_pa = memblock_phys_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);
+ if (!nd_pa)
+ panic("Cannot allocate %zu bytes for node %d data\n",
+ nd_size, nid);
+ nd = __va(nd_pa);
+
+ /* report and initialize */
+ pr_info("NODE_DATA(%d) allocated [mem %#010Lx-%#010Lx]\n", nid,
+ nd_pa, nd_pa + nd_size - 1);
+ tnid = early_pfn_to_nid(nd_pa >> PAGE_SHIFT);
+ if (tnid != nid)
+ pr_info(" NODE_DATA(%d) on node %d\n", nid, tnid);
+
+ node_data[nid] = nd;
+ memset(NODE_DATA(nid), 0, sizeof(pg_data_t));
+}

I might have missed some architecture except x86 that calls
node_set_online() in its alloc_node_data(), but the intention was to leave
that call outside the alloc and explicitly add it after the call to
alloc_node_data() if needed like in x86.

> --
> Cheers,
>
> David / dhildenb
>
>

--
Sincerely yours,
Mike.