Re: [PATCH v2 2/3] mm, page_owner: decouple freeing stack trace from debug_pagealloc

Vlastimil Babka
2019-10-01T08:07:49Z

On 10/1/19 1:49 AM, Qian Cai wrote:
>
>
>> On Sep 30, 2019, at 5:43 PM, Vlastimil Babka <vbabka@suse.cz> wrote:
>>
>> Well, my use case is shipping production kernels with CONFIG_PAGE_OWNER
>> and CONFIG_DEBUG_PAGEALLOC enabled, and instructing users to boot-time
>> enable only for troubleshooting a crash or memory leak, without a need
>> to install a debug kernel. Things like static keys and page_ext
>> allocations makes this possible without CPU and memory overhead when not
>> boot-time enabled. I don't know too much about KASAN internals, but I
>> assume it's not possible to use it that way on production kernels yet?
>
> In that case, why can’t users just simply enable page_owner=on and debug_pagealloc=on for troubleshooting? The later makes the kernel slower, but I am not sure if it is worth optimization by adding a new parameter. There have already been quite a few MM-related kernel parameters that could tidy up a bit in the future.

They can do that and it was intention, yes. The extra parameter was
requested by Kirill, so I'll defer the answer to him :)