在 2020/11/5 下午11:36, Johannes Weiner 写道:

quoted

quoted

	 */

Yeah, I don't think this scenario warrants the full race diagram in
the code itself.

But the code is highly specific - synchronizing one struct page member
for one particular use case. Let's keep at least a reference to what
we are synchronizing against. There is a non-zero chance that if the
comment goes out of date, so does the code. How about this?

	/*
	 * page_idle does a lockless/optimistic rmap scan on page->mapping.
	 * Make sure the compiler doesn't split the stores of anon_vma and
	 * the PAGE_MAPPING_ANON type identifier, otherwise the rmap code
	 * could mistake the mapping for a struct address_space and crash.
	 */

Thanks a lot to you all. I will update to v21 patch

Alex