On Thu, 30 Jul 2009, Robin Holt wrote: > > > On Wednesday 29 July 2009 17:26:11 Hugh Dickins wrote: > ... > > > > On the other hand, despite the raised reference count, under memory > > > > pressure that page might get unmapped from the user pagetable, and > > > > might even be written out to swap in its half-dirty state (though > > One thing you did not mention in the above description is that the page > is marked clean by the write-out to swap. I am not sure I recall the > method of mapping involved here, but it is necessary to ensure the page > is marked dirty again before the driver releases it. If the page is > not marked dirty as part of your method of releasing it, the changes > you have made between when the page was first written out and when you > are freeing it will get lost. Yes indeed: thanks, Robin. Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
