From: David Hildenbrand <david@xxxxxxxxxx> Subject: drivers/base/memory.c: don't store end_section_nr in memory blocks Each memory block spans the same amount of sections/pages/bytes. The size is determined before the first memory block is created. No need to store what we can easily calculate - and the calculations even look simpler now. Michal brought up the idea of variable-sized memory blocks. However, if we ever implement something like this, we will need an API compatibility switch and reworks at various places (most code assumes a fixed memory block size). So let's cleanup what we have right now. While at it, fix the variable naming in register_mem_sect_under_node() - we no longer talk about a single section. Link: http://lkml.kernel.org/r/20190809110200.2746-1-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/base/memory.c | 1 - drivers/base/node.c | 10 +++++----- include/linux/memory.h | 1 - mm/memory_hotplug.c | 2 +- 4 files changed, 6 insertions(+), 8 deletions(-) --- a/drivers/base/memory.c~drivers-base-memoryc-dont-store-end_section_nr-in-memory-blocks +++ a/drivers/base/memory.c @@ -656,7 +656,6 @@ static int init_memory_block(struct memo return -ENOMEM; mem->start_section_nr = block_id * sections_per_block; - mem->end_section_nr = mem->start_section_nr + sections_per_block - 1; mem->state = state; start_pfn = section_nr_to_pfn(mem->start_section_nr); mem->phys_device = arch_get_memory_phys_device(start_pfn); --- a/drivers/base/node.c~drivers-base-memoryc-dont-store-end_section_nr-in-memory-blocks +++ a/drivers/base/node.c @@ -756,13 +756,13 @@ static int __ref get_nid_for_pfn(unsigne static int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg) { + unsigned long memory_block_pfns = memory_block_size_bytes() / PAGE_SIZE; + unsigned long start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); + unsigned long end_pfn = start_pfn + memory_block_pfns - 1; int ret, nid = *(int *)arg; - unsigned long pfn, sect_start_pfn, sect_end_pfn; + unsigned long pfn; - sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); - sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); - sect_end_pfn += PAGES_PER_SECTION - 1; - for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { + for (pfn = start_pfn; pfn <= end_pfn; pfn++) { int page_nid; /* --- a/include/linux/memory.h~drivers-base-memoryc-dont-store-end_section_nr-in-memory-blocks +++ a/include/linux/memory.h @@ -25,7 +25,6 @@ struct memory_block { unsigned long start_section_nr; - unsigned long end_section_nr; unsigned long state; /* serialized by the dev->lock */ int section_count; /* serialized by mem_sysfs_mutex */ int online_type; /* for passing data to online routine */ --- a/mm/memory_hotplug.c~drivers-base-memoryc-dont-store-end_section_nr-in-memory-blocks +++ a/mm/memory_hotplug.c @@ -1654,7 +1654,7 @@ static int check_memblock_offlined_cb(st phys_addr_t beginpa, endpa; beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); - endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1; + endpa = beginpa + memory_block_size_bytes() - 1; pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n", &beginpa, &endpa); _
