Messages in this thread | | | Date | Mon, 31 Aug 2015 18:24:36 +0300 | From | Vladimir Davydov <> | Subject | Re: [PATCH 0/2] Fix memcg/memory.high in case kmem accounting is enabled |
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On Mon, Aug 31, 2015 at 10:46:04AM -0400, Tejun Heo wrote: > Hello, Vladimir. > > On Mon, Aug 31, 2015 at 05:20:49PM +0300, Vladimir Davydov wrote: > ... > > That being said, this is the fix at the right layer. > > While this *might* be a necessary workaround for the hard limit case > right now, this is by no means the fix at the right layer. The > expectation is that mm keeps a reasonable amount of memory available > for allocations which can't block. These allocations may fail from > time to time depending on luck and under extreme memory pressure but > the caller should be able to depend on it as a speculative allocation > mechanism which doesn't fail willy-nilly. > > Hardlimit breaking GFP_NOWAIT behavior is a bug on memcg side, not > slab or slub.
I never denied that there is GFP_NOWAIT/GFP_NOFS problem in memcg. I even proposed ways to cope with it in one of the previous e-mails.
Nevertheless, we just can't allow slab/slub internals call memcg_charge whenever they want as I pointed out in a parallel thread.
Thanks, Vladimir
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