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Subject: Re: [PATCH] mm: memblock: add more debug logs
To:     Mike Rapoport <rppt@kernel.org>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        vinmenon@codeaurora.org
References: <1605010798-17545-1-git-send-email-faiyazm@codeaurora.org>
 <20201110181605.GC4758@kernel.org>
From:   Faiyaz Mohammed <faiyazm@codeaurora.org>
Message-ID: <f1e3c3c8-ed4f-9283-e221-7faec10fdd8d@codeaurora.org>
Date:   Wed, 11 Nov 2020 13:30:40 +0530
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On 11/10/2020 11:46 PM, Mike Rapoport wrote:
> Hi,
>
> On Tue, Nov 10, 2020 at 05:49:58PM +0530, Faiyaz Mohammed wrote:
>> Exact caller of memblock_phys_alloc_range is not available with
>> "memblock=debug". Below information is not enough for memory accounting.
>> for example:
>> [    0.000000] memblock_reserve: [0x000000023fc6b000-0x000000023fc6bfff] memblock_alloc_range_nid+0xc0/0x188
>>
>> To enhance the memblock_dbg information or to get the exact owner of the
>> memblock_reserve, add debug logs in memblock_phys_alloc_range function.
> Why would you want to use memblock=debug for memory accounting or for
> tracking of the owners of the reserved memory?
We do memblock reserved accounting to track owners to know size of memory

allocated by different drivers/owners through memblock_reserve, which help

in comparing different kernel version and in optimizations.

>
>> After adding logs:
>> [    0.000000] memblock_phys_alloc_range: 4096 bytes align=0x1000 from=0x0000000000000000 max_addr=0x0000000000000000 early_pgtable_alloc+0x24/0x178
>> [    0.000000] memblock_reserve: [0x000000023fc6b000-0x000000023fc6bfff] memblock_alloc_range_nid+0xc0/0x188
>>
>> Signed-off-by: Faiyaz Mohammed <faiyazm@codeaurora.org>
>> ---
>>   mm/memblock.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/mm/memblock.c b/mm/memblock.c
>> index 049df41..f65af9f 100644
>> --- a/mm/memblock.c
>> +++ b/mm/memblock.c
>> @@ -1419,6 +1419,9 @@ phys_addr_t __init memblock_phys_alloc_range(phys_addr_t size,
>>   					     phys_addr_t start,
>>   					     phys_addr_t end)
>>   {
>> +	memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pS\n",
>> +			__func__, (u64)size, (u64)align, &start, &end,
>> +			(void *)_RET_IP_);
>>   	return memblock_alloc_range_nid(size, align, start, end, NUMA_NO_NODE,
>>   					false);
>>   }
>> -- 
>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
>> member of the Code Aurora Forum, hosted by The Linux Foundation
>>