Thread (23 messages) 23 messages, 6 authors, 2021-06-09

Re: [PATCH v1 05/12] mm/memory_hotplug: remove nid parameter from remove_memory() and friends

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2021-06-08 11:12:07
Also in: linux-acpi, linuxppc-dev, lkml, nvdimm, virtualization

David Hildenbrand [off-list ref] writes:
There is only a single user remaining. We can simply try to offline all
online nodes - which is fast, because we usually span pages and can skip
such nodes right away.
That makes me slightly nervous, because our big powerpc boxes tend to
trip on these scaling issues before others.

But the spanned pages check is just:

void try_offline_node(int nid)
{
	pg_data_t *pgdat = NODE_DATA(nid);
        ...
	if (pgdat->node_spanned_pages)
		return;

So I guess that's pretty cheap, and it's only O(nodes), which should
never get that big.
quoted hunk ↗ jump to hunk
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <redacted>
Cc: "Rafael J. Wysocki" <redacted>
Cc: Len Brown <lenb@kernel.org>
Cc: Dan Williams <redacted>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nathan Lynch <redacted>
Cc: Laurent Dufour <redacted>
Cc: "Aneesh Kumar K.V" <redacted>
Cc: Scott Cheloha <redacted>
Cc: Anton Blanchard <redacted>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-acpi@vger.kernel.org
Cc: nvdimm@lists.linux.dev
Signed-off-by: David Hildenbrand <redacted>
---
 .../platforms/pseries/hotplug-memory.c        |  9 ++++-----
 drivers/acpi/acpi_memhotplug.c                |  7 +------
 drivers/dax/kmem.c                            |  3 +--
 drivers/virtio/virtio_mem.c                   |  4 ++--
 include/linux/memory_hotplug.h                | 10 +++++-----
 mm/memory_hotplug.c                           | 20 +++++++++----------
 6 files changed, 23 insertions(+), 30 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 8377f1f7c78e..4a9232ddbefe 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -286,7 +286,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned long memblock_si
 {
 	unsigned long block_sz, start_pfn;
 	int sections_per_block;
-	int i, nid;
+	int i;
 
 	start_pfn = base >> PAGE_SHIFT;
 
@@ -297,10 +297,9 @@ static int pseries_remove_memblock(unsigned long base, unsigned long memblock_si
 
 	block_sz = pseries_memory_block_size();
 	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
-	nid = memory_add_physaddr_to_nid(base);
 
 	for (i = 0; i < sections_per_block; i++) {
-		__remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
+		__remove_memory(base, MIN_MEMORY_BLOCK_SIZE);
 		base += MIN_MEMORY_BLOCK_SIZE;
 	}
 
@@ -386,7 +385,7 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
 
 	block_sz = pseries_memory_block_size();
 
-	__remove_memory(mem_block->nid, lmb->base_addr, block_sz);
+	__remove_memory(lmb->base_addr, block_sz);
 	put_device(&mem_block->dev);
 
 	/* Update memory regions for memory remove */
@@ -638,7 +637,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
 
 	rc = dlpar_online_lmb(lmb);
 	if (rc) {
-		__remove_memory(nid, lmb->base_addr, block_sz);
+		__remove_memory(lmb->base_addr, block_sz);
 		invalidate_lmb_associativity_index(lmb);
 	} else {
 		lmb->flags |= DRCONF_MEM_ASSIGNED;

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers
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