Re: [PATCH] mm, show_mem: drop pgdat_resize_lock in show_mem()

[Wei Yang <richard.weiyang@gmail.com>]

On Thu, Nov 29, 2018 at 05:18:47PM +0100, Michal Hocko wrote:
>On Thu 29-11-18 16:05:24, Wei Yang wrote:
>> On Thu, Nov 29, 2018 at 04:49:22PM +0100, Michal Hocko wrote:
>[...]
>> >It is only called from __remove_pages and that one calls cond_resched so
>> >obviosly not.
>> >
>> 
>> Forgive my poor background knowledge, I went throught the code, but not
>> found where call cond_resched.
>> 
>>   __remove_pages()
>>     release_mem_region_adjustable()
>>     clear_zone_contiguous()
>>     __remove_section()
>>       unregister_memory_section()
>>       __remove_zone()
>>       sparse_remove_one_section()
>>     set_zone_contiguous()
>> 
>> Would you mind giving me a hint?
>
>This is the code as of 4.20-rc2
>
>	for (i = 0; i < sections_to_remove; i++) {
>		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
>
>		cond_resched();
>		ret = __remove_section(zone, __pfn_to_section(pfn), map_offset,
>				altmap);
>		map_offset = 0;
>		if (ret)
>			break;
>	}
>
>Maybe things have changed in the meantime but in general the code is
>sleepable (e.g. release_mem_region_adjustable does GFP_KERNEL
>allocation) and that rules out IRQ context.

Thanks, my code is not up to date.

>-- 
>Michal Hocko
>SUSE Labs

-- 
Wei Yang
Help you, Help me