On Mon, Jul 20, 2015 at 09:24:40PM +0200, Oleg Nesterov wrote: > On 07/20, Oleg Nesterov wrote: > > > > But again, again, please ignore. This all is off-topic and my understanding > > is very limited. > > Yes, yes, but sorry for noise and let me repeat... > > This memory lives in page-cache/lru, it is visible for shrinker which > will unmap these pages for no reason on memory shortage. IOW, aio fools > the kernel, this memory looks reclaimable but it is not. And we only do > this for migration. And we have the same problem with O_DIRECT. Given the size of the LRU in a modern system, I highly doubt a handful of pages getting scanned is a major problem. If you want to improve this, go ahead, but we need to retain support for page migration as people have run into the need for it. > Even if this is not a problem, this does not look right. So perhaps at > least mapping_set_unevictable() makes sense. But I simply do not know > if migration will work with this change. Nor do I know if that will work. > And I should have changes the subject a long ago... So what do you think > we should do with the build failure? I honestly don't care what of the options you do -- please just don't go about adding BUG()s. -ben > Oleg. -- "Thought is the essence of where you are now." -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
