Messages in this thread | | | Subject | Re: [PATCH v1] mm: page_alloc: Add debug log in free_reserved_area for static memory | From | David Hildenbrand <> | Date | Wed, 29 Sep 2021 19:03:50 +0200 |
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On 29.09.21 10:58, Faiyaz Mohammed wrote: > > > On 9/28/2021 4:46 PM, David Hildenbrand wrote: >> On 28.09.21 12:53, Faiyaz Mohammed wrote: >>> >>> >>> On 9/28/2021 4:09 PM, David Hildenbrand wrote: >>>> On 28.09.21 11:04, Faiyaz Mohammed wrote: >>>>> For INITRD and initmem memory is reserved through "memblock_reserve" >>>>> during boot up but it is free via "free_reserved_area" instead >>>>> of "memblock_free". >>>>> For example: >>>>> [ 0.294848] Freeing initrd memory: 12K. >>>>> [ 0.696688] Freeing unused kernel memory: 4096K. >>>>> >>>>> To get the start and end address of the above freed memory and to >>>>> account >>>>> proper memblock added memblock_dbg log in "free_reserved_area". >>>>> After adding log: >>>>> [ 0.294837] memblock_free: [0x00000083600000-0x00000083603000] >>>>> free_initrd_mem+0x20/0x28 >>>>> [ 0.294848] Freeing initrd memory: 12K. >>>>> [ 0.695246] memblock_free: [0x00000081600000-0x00000081a00000] >>>>> free_initmem+0x70/0xc8 >>>>> [ 0.696688] Freeing unused kernel memory: 4096K. >>>>> >>>>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org> >>>>> --- >>>>> mm/page_alloc.c | 5 +++++ >>>>> 1 file changed, 5 insertions(+) >>>>> >>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>>>> index b37435c..f85c3b2 100644 >>>>> --- a/mm/page_alloc.c >>>>> +++ b/mm/page_alloc.c >>>>> @@ -8129,6 +8129,11 @@ unsigned long free_reserved_area(void *start, >>>>> void *end, int poison, const char >>>>> pr_info("Freeing %s memory: %ldK\n", >>>>> s, pages << (PAGE_SHIFT - 10)); >>>>> +#ifdef CONFIG_HAVE_MEMBLOCK >>>>> + memblock_dbg("memblock_free: [%#016llx-%#016llx] %pS\n", >>>>> + __pa(start), __pa(end), (void *)_RET_IP_); >>>>> +#endif >>>> >>>> IMHO, the "memblock_free" part is misleading. Something was allocated >>>> early via memblock, then we transitioned to the buddy, now we're freeing >>>> that early allocation via the buddy. >>>> Yes, we're freeing the early allocation via buddy, but for proper >>> memblock accounting we need this debug print. >>> >> >> What do you mean with "accounting" ? These are debug statements. >> >> > Yes, these are debug statements, which help to know the a-b address > belongs to x callsite. This info is required when memblock=debug is > passed through command line and CONFIG_HAVE_MEMBLOCK is enabled.
The issue I'm having is talking in the name of memblock "memblock_dbg, memblock_free", when memblock might no longer be around. We have other places where we free early memblock allocations back to the buddy.
-- Thanks,
David / dhildenb
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