On 25 April 2012 07:30, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 24 Apr 2012 17:48:29 +1000 > Nick Piggin <npiggin@xxxxxxxxx> wrote: > >> > Hmm, there are several places to use GFP_NOIO and GFP_NOFS even, GFP_ATOMIC. >> > I believe it's not trivial now. >> >> They're all buggy then. Unfortunately not through any real fault of their own. > > There are gruesome problems in block/blk-throttle.c (thread "mempool, > percpu, blkcg: fix percpu stat allocation and remove stats_lock"). It > wants to do an alloc_percpu()->vmalloc() from the IO submission path, > under GFP_NOIO. Yeah, that sucks. CFQ has something similar. Should just allocate it up front when creating a throttled group. Allocate and init when it first gets used schemes are usually pretty problematic. Is it *really* warranted to do it lazily like this? > Changing vmalloc() to take a gfp_t does make lots of sense, although I > worry a bit about making vmalloc() easier to use! > > I do wonder whether the whole scheme of explicitly passing a gfp_t was > a mistake and that the allocation context should be part of the task > context. ie: pass the allocation mode via *current. As a handy > side-effect that would probably save quite some code where functions > are receiving a gfp_t arg then simply passing it on to the next > callee. Both paragraphs make a lot of sense. Conceptually. :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href