On Thu, Jul 28 2016, Michal Hocko wrote: > On Wed 27-07-16 13:43:35, NeilBrown wrote: >> On Mon, Jul 25 2016, Michal Hocko wrote: >> >> > On Sat 23-07-16 10:12:24, NeilBrown wrote: > [...] >> So should there be a limit on dirty >> pages in the swap cache just like there is for dirty pages in any >> filesystem (the max_dirty_ratio thing) ?? >> Maybe there is? > > There is no limit AFAIK. We are relying that the reclaim is throttled > when necessary. Is that a bit indirect? It is hard to tell without a clear big-picture. Something to keep in mind anyway. > >> I think we'd end up with cleaner code if we removed the cute-hacks. And >> we'd be able to use 6 more GFP flags!! (though I do wonder if we really >> need all those 26). > > Well, maybe we are able to remove those hacks, I wouldn't definitely > be opposed. But right now I am not even convinced that the mempool > specific gfp flags is the right way to go. I'm not suggesting a mempool-specific gfp flag. I'm suggesting a transient-allocation gfp flag, which would be quite useful for mempool. Can you give more details on why using a gfp flag isn't your first choice for guiding what happens when the system is trying to get a free page :-? Thanks, NeilBrown
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