NUMA: optimize detection of memory with no node id assigned by firmware

Sanity check that makes sure the nodes cover all memory loops over
numa_meminfo to count the pages that have node id assigned by the
firmware, then loops again over memblock.memory to find the total amount
of memory and in the end checks that the difference between the total
memory and memory that covered by nodes is less than some threshold. 
Worse, the loop over numa_meminfo calls __absent_pages_in_range() that
also partially traverses memblock.memory.

It's much simpler and more efficient to have a single traversal of
memblock.memory that verifies that amount of memory not covered by nodes
is less than a threshold.

Introduce memblock_validate_numa_coverage() that does exactly that and use
it instead of numa_meminfo_cover_memory().

Link: https://lkml.kernel.org/r/20231026020329.327329-1-zhiguangni01@gmail.com
Signed-off-by: Liam Ni <zhiguangni01@gmail.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Binbin Zhou <zhoubinbin@loongson.cn>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feiyang Chen <chenfeiyang@loongson.cn>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 3 insertions, 59 deletions

diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c
index 6e65ff12d5c7..8fe21f868f72 100644
--- a/arch/loongarch/kernel/numa.c
+++ b/arch/loongarch/kernel/numa.c
@@ -226,32 +226,6 @@ static void __init node_mem_init(unsigned int node)
 
 #ifdef CONFIG_ACPI_NUMA
 
-/*
- * Sanity check to catch more bad NUMA configurations (they are amazingly
- * common).  Make sure the nodes cover all memory.
- */
-static bool __init numa_meminfo_cover_memory(const struct numa_meminfo *mi)
-{
-	int i;
-	u64 numaram, biosram;
-
-	numaram = 0;
-	for (i = 0; i < mi->nr_blks; i++) {
-		u64 s = mi->blk[i].start >> PAGE_SHIFT;
-		u64 e = mi->blk[i].end >> PAGE_SHIFT;
-
-		numaram += e - s;
-		numaram -= __absent_pages_in_range(mi->blk[i].nid, s, e);
-		if ((s64)numaram < 0)
-			numaram = 0;
-	}
-	max_pfn = max_low_pfn;
-	biosram = max_pfn - absent_pages_in_range(0, max_pfn);
-
-	BUG_ON((s64)(biosram - numaram) >= (1 << (20 - PAGE_SHIFT)));
-	return true;
-}
-
 static void __init add_node_intersection(u32 node, u64 start, u64 size, u32 type)
 {
 	static unsigned long num_physpages;
@@ -396,7 +370,7 @@ int __init init_numa_memory(void)
 		return -EINVAL;
 
 	init_node_memblock();
-	if (numa_meminfo_cover_memory(&numa_meminfo) == false)
+	if (!memblock_validate_numa_coverage(SZ_1M))
 		return -EINVAL;
 
 	for_each_node_mask(node, node_possible_map) {
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index b29ceb19e46e..adc497b93f03 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -450,37 +450,6 @@ int __node_distance(int from, int to)
 EXPORT_SYMBOL(__node_distance);
 
 /*
- * Sanity check to catch more bad NUMA configurations (they are amazingly
- * common).  Make sure the nodes cover all memory.
- */
-static bool __init numa_meminfo_cover_memory(const struct numa_meminfo *mi)
-{
-	u64 numaram, e820ram;
-	int i;
-
-	numaram = 0;
-	for (i = 0; i < mi->nr_blks; i++) {
-		u64 s = mi->blk[i].start >> PAGE_SHIFT;
-		u64 e = mi->blk[i].end >> PAGE_SHIFT;
-		numaram += e - s;
-		numaram -= __absent_pages_in_range(mi->blk[i].nid, s, e);
-		if ((s64)numaram < 0)
-			numaram = 0;
-	}
-
-	e820ram = max_pfn - absent_pages_in_range(0, max_pfn);
-
-	/* We seem to lose 3 pages somewhere. Allow 1M of slack. */
-	if ((s64)(e820ram - numaram) >= (1 << (20 - PAGE_SHIFT))) {
-		printk(KERN_ERR "NUMA: nodes only cover %LuMB of your %LuMB e820 RAM. Not used.\n",
-		       (numaram << PAGE_SHIFT) >> 20,
-		       (e820ram << PAGE_SHIFT) >> 20);
-		return false;
-	}
-	return true;
-}
-
-/*
  * Mark all currently memblock-reserved physical memory (which covers the
  * kernel's own memory ranges) as hot-unswappable.
  */
@@ -585,7 +554,8 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
 			return -EINVAL;
 		}
 	}
-	if (!numa_meminfo_cover_memory(mi))
+
+	if (!memblock_validate_numa_coverage(SZ_1M))
 		return -EINVAL;
 
 	/* Finally register nodes. */