Re: [PATCH 04/21] mm: zap_pte_range dont dirty anon

[Hugh Dickins]

On Sun, 25 Sep 2005, Andrew Morton wrote:
> 
> 	mmap(MAP_ANONYMOUS|MAP_SHARED)
> 	fork()
> 	swapout
> 	swapin
> 	swapoff
> 
> Now we have two mm's sharing a clean, non-cowable, non-swapcache anonymous
> page, no?

No, MAP_ANONYMOUS|MAP_SHARED gives you a tmpfs object via shmem_zero_setup:
all those pages are shared file pages, not PageAnon at all.

Hugh
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