Re: [Patch v2] selftests/mm: check content to see whether mremap corrupt data

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

On Tue, Sep 02, 2025 at 10:23:51AM +0200, David Hildenbrand wrote:
>On 02.09.25 10:13, Wei Yang wrote:
>> On Tue, Sep 02, 2025 at 09:49:48AM +0200, David Hildenbrand wrote:
>> > > > +	/*
>> > > > +	 * To challenge spitting code, we will mremap page[x] of the
>> > > > +	 * thp[x] into a smaller area, and trigger the split from that
>> > > > +	 * smaller area. This will end up replacing the PMD mappings in
>> > > > +	 * the thp_area by PTE mappings first, leaving the THPs unsplit.
>> > > > +	 */
>> 
>> This confuse me a little. How about move "and trigger the split from that
>> smaller area" to the end? So that I know mremap convert to pte-mapping and
>> leave thp unsplit. Then we do the split.
>> 
>
>After spleeping over it, what about the following?
>
>+       /*
>+        * To challenge spitting code, we will mremap a single page of each
>+        * THP (page[i] of thp[i]) in the thp_area into page_area. This will
>+        * replace the PMD mappings in the thp_area by PTE mappings first,
>+        * but leaving the THP unsplit, to then create a page-sized hole in
>+        * the thp_area.
>+        * We will then manually trigger splitting of all THPs through the
>+        * single mremap'ed pages of each THP in the page_area.
>+        */
>

Much better, thanks :-)


-- 
Wei Yang
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