On Fri, Aug 02, 2024 at 05:07:48PM -0700, Nathan Chancellor wrote:
>Hi Wei,
>
>On Fri, Jul 26, 2024 at 12:36:12AM +0000, Wei Yang wrote:
>> Total memory represents pages managed by buddy system. After the
>> introduction of DEFERRED_STRUCT_PAGE_INIT, it may count the pages before
>> being managed.
>>
>> free_low_memory_core_early() returns number of pages for all free pages,
>> even at this moment only early initialized pages are freed to buddy
>> system. This means the total memory at this moment is not correct.
>>
>> Let's increase it when pages are freed to buddy system.
>>
>> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
>> CC: David Hildenbrand <david@xxxxxxxxxx>
>>
>> ---
>> v2:
>> * rebase on current master
>> * those places would be affected are merged
>> ---
>> mm/memblock.c | 22 ++++++----------------
>> mm/page_alloc.c | 4 +---
>> 2 files changed, 7 insertions(+), 19 deletions(-)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 213057603b65..592a22b64682 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -1711,10 +1711,8 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
>> cursor = PFN_UP(base);
>> end = PFN_DOWN(base + size);
>>
>> - for (; cursor < end; cursor++) {
>> + for (; cursor < end; cursor++)
>> memblock_free_pages(pfn_to_page(cursor), cursor, 0);
>> - totalram_pages_inc();
>> - }
>> }
>>
>> /*
>> @@ -2140,7 +2138,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
>> }
>> }
>>
>> -static unsigned long __init __free_memory_core(phys_addr_t start,
>> +static void __init __free_memory_core(phys_addr_t start,
>> phys_addr_t end)
>> {
>> unsigned long start_pfn = PFN_UP(start);
>> @@ -2148,11 +2146,9 @@ static unsigned long __init __free_memory_core(phys_addr_t start,
>> PFN_DOWN(end), max_low_pfn);
>>
>> if (start_pfn >= end_pfn)
>> - return 0;
>> + return;
>>
>> __free_pages_memory(start_pfn, end_pfn);
>> -
>> - return end_pfn - start_pfn;
>> }
>>
>> static void __init memmap_init_reserved_pages(void)
>> @@ -2194,9 +2190,8 @@ static void __init memmap_init_reserved_pages(void)
>> }
>> }
>>
>> -static unsigned long __init free_low_memory_core_early(void)
>> +static void __init free_low_memory_core_early(void)
>> {
>> - unsigned long count = 0;
>> phys_addr_t start, end;
>> u64 i;
>>
>> @@ -2211,9 +2206,7 @@ static unsigned long __init free_low_memory_core_early(void)
>> */
>> for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end,
>> NULL)
>> - count += __free_memory_core(start, end);
>> -
>> - return count;
>> + __free_memory_core(start, end);
>> }
>>
>> static int reset_managed_pages_done __initdata;
>> @@ -2244,13 +2237,10 @@ void __init reset_all_zones_managed_pages(void)
>> */
>> void __init memblock_free_all(void)
>> {
>> - unsigned long pages;
>> -
>> free_unused_memmap();
>> reset_all_zones_managed_pages();
>>
>> - pages = free_low_memory_core_early();
>> - totalram_pages_add(pages);
>> + free_low_memory_core_early();
>> }
>>
>> /* Keep a table to reserve named memory */
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index 71d2716a554f..4701bc442df6 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -1248,16 +1248,14 @@ void __meminit __free_pages_core(struct page *page, unsigned int order,
>> * map it first.
>> */
>> debug_pagealloc_map_pages(page, nr_pages);
>> - adjust_managed_page_count(page, nr_pages);
>> } else {
>> for (loop = 0; loop < nr_pages; loop++, p++) {
>> __ClearPageReserved(p);
>> set_page_count(p, 0);
>> }
>>
>> - /* memblock adjusts totalram_pages() manually. */
>> - atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
>> }
>> + adjust_managed_page_count(page, nr_pages);
>>
>> if (page_contains_unaccepted(page, order)) {
>> if (order == MAX_PAGE_ORDER && __free_unaccepted(page))
>> --
>> 2.34.1
>>
>>
>
>After this change as commit 0e690b558b53 ("mm: increase totalram_pages
>on freeing to buddy system") in -next, I see an issue when booting
>OpenSUSE's powerpc64le configuration in QEMU (I have not tried to see if
>there is a specific configuration option triggers this yet but it does
>not happen with all of my powerpc configurations):
>
>$ curl -LSso .config https://github.com/openSUSE/kernel-source/raw/master/config/ppc64le/default
>
>$ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64-linux- olddefconfig zImage.epapr
>
>$ qemu-system-ppc64 \
> -display none \
> -nodefaults \
> -device ipmi-bmc-sim,id=bmc0 \
> -device isa-ipmi-bt,bmc=bmc0,irq=10 \
> -machine powernv \
> -kernel arch/powerpc/boot/zImage.epapr \
> -initrd rootfs.cpio \
> -m 2G \
> -serial mon:stdio
Hi, Nathan
Thanks for testing.
After some debug, the broken point is in mm/shmem.c. Function
shmem_default_max_blocks() / shmem_default_max_inodex() is called by
shmem_fill_super() during early stage.
But I can't get the total free pages from memblock here as those functions
will be called later, when memblock is discarded.
I may need to find other way to handle it.
--
Wei Yang
Help you, Help me
