Re: [PATCH] mm: move page_ext_init after all struct pages are initialized

["Shi, Yang" <yang.shi@linaro.org>]

On 5/19/2016 4:21 PM, Andrew Morton wrote:
> On Thu, 19 May 2016 15:35:15 -0700 "Shi, Yang" <yang.shi@linaro.org> wrote:
>
>> On 5/19/2016 3:30 PM, Andrew Morton wrote:
>>> On Thu, 19 May 2016 14:29:05 -0700 Yang Shi <yang.shi@linaro.org> wrote:
>>>
>>>> When DEFERRED_STRUCT_PAGE_INIT is enabled, just a subset of memmap at boot
>>>> are initialized, then the rest are initialized in parallel by starting one-off
>>>> "pgdatinitX" kernel thread for each node X.
>>>>
>>>> If page_ext_init is called before it, some pages will not have valid extension,
>>>> so move page_ext_init() after it.
>>>>
>>>
>>> <stdreply>When fixing a bug, please fully describe the end-user impact
>>> of that bug</>
>>
>> The kernel ran into the below oops which is same with the oops reported
>> in
>> http://ozlabs.org/~akpm/mmots/broken-out/mm-page_is_guard-return-false-when-page_ext-arrays-are-not-allocated-yet.patch.
>
> So this patch makes
> mm-page_is_guard-return-false-when-page_ext-arrays-are-not-allocated-yet.patch
> obsolete?

Actually, no. Checking the return value for lookup_page_ext() is still 
needed. But, the commit log need to be amended since that bootup oops 
won't happen anymore with this patch applied.

Thanks,
Yang

>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>