Messages in this thread | | | Date | Mon, 28 Nov 2016 12:19:07 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH] block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg |
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Hello,
On Wed, Nov 23, 2016 at 09:50:12AM +0100, Vlastimil Babka wrote: > > You'd certainly _hope_ that atomic allocations either have fallbacks > > or are harmless if they fail, but I'd still rather see that > > __GFP_NOWARN just to make that very much explicit. > > A global change to GFP_NOWAIT would of course mean that we should audit its > users (there don't seem to be many), whether they are using it consciously > and should not rather be using GFP_ATOMIC.
A while ago, I thought about something like, say, GFP_MAYBE which is combination of NOWAIT and NOWARN but couldn't really come up with scenarios where one would want to use NOWAIT w/o NOWARN. If an allocation is important enough to warn the user of its failure, it better be dipping into the atomic reserve pool; otherwise, it doesn't make sense to make noise.
Maybe we can come up with a better name which signifies that this is likely to fail every now and then but I still think it'd be beneficial to make it quiet by default. Linus, do you still think NOWARN should be explicit?
Thanks.
-- tejun
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