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

Wei Yang
2018-11-29T23:49:59Z

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