On Sat, Oct 21, 2023 at 09:15:20PM +0800, Liam Ni wrote: > 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(). > > Signed-off-by: Liam Ni <zhiguangni01@xxxxxxxxx> > --- > arch/loongarch/kernel/numa.c | 28 +--------------------------- > arch/x86/mm/numa.c | 34 ++-------------------------------- > include/linux/memblock.h | 1 + > mm/memblock.c | 34 ++++++++++++++++++++++++++++++++++ > 4 files changed, 38 insertions(+), 59 deletions(-) > > diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c > index cb00804826f7..84e1b046ab52 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 >> PAGE_SIZE)) > 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 2aadb2019b4f..39772d551924 100644 > --- a/arch/x86/mm/numa.c > +++ b/arch/x86/mm/numa.c > @@ -447,37 +447,6 @@ 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. > @@ -583,7 +552,8 @@ 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 >> PAGE_SIZE)) > return -EINVAL; > > /* Finally register nodes. */ > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 1c1072e3ca06..727242f4b54a 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -120,6 +120,7 @@ int memblock_physmem_add(phys_addr_t base, > phys_addr_t size); > void memblock_trim_memory(phys_addr_t align); > bool memblock_overlaps_region(struct memblock_type *type, > phys_addr_t base, phys_addr_t size); > +bool memblock_validate_numa_coverage(const u64 threshold_pages); > int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > diff --git a/mm/memblock.c b/mm/memblock.c > index 0863222af4a4..ebea0c204eaa 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -734,6 +734,40 @@ int __init_memblock memblock_add(phys_addr_t > base, phys_addr_t size) > return memblock_add_range(&memblock.memory, base, size, MAX_NUMNODES, 0); > } > > +/** > + * memblock_validate_numa_coverage - check if amount of memory with > + * no node ID assigned is less than a threshold > + * @threshold_pages: maximal number of pages that can have unassigned node > + * ID (in pages). > + * > + * A buggy firmware may report memory that does not belong to any node. > + * Check if amount of such memory is below @threshold_pages. > + * > + * Return: true on success, false on failure. > + */ > +bool __init_memblock memblock_validate_numa_coverage(const u64 threshold_pages) With threshold in bytes there will be less conversions from pages to bytes. Also, I don't think const has much value here and unsigned long should suffice. > +{ > + unsigned long nr_pages = 0; > + unsigned long start_pfn, end_pfn, mem_size_mb; > + int nid, i; > + > + /* calculate lose page */ > + for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) { > + if (nid == NUMA_NO_NODE) > + nr_pages += end_pfn - start_pfn; > + } > + > + if (nr_pages >= threshold_pages) { > + mem_size_mb = memblock_phys_mem_size() >> 20; > + pr_err("NUMA: no nodes coverage for %luMB of %luMB RAM\n", > + (nr_pages << PAGE_SHIFT) >> 20, mem_size_mb); > + return false; > + } > + > + return true; > +} > + > + > /** > * memblock_isolate_range - isolate given range into disjoint memblocks > * @type: memblock type to isolate range for > -- > 2.25.1 -- Sincerely yours, Mike.