On Fri, 11 Mar 2011, Prasad Joshi wrote: > A filesystem might run into a problem while calling > __vmalloc(GFP_NOFS) inside a lock. > > It is expected than __vmalloc when called with GFP_NOFS should not > callback the filesystem code even incase of the increased memory > pressure. But the problem is that even if we pass this flag, __vmalloc > itself allocates memory with GFP_KERNEL. > > Using GFP_KERNEL allocations may go into the memory reclaim path and > try to free memory by calling file system clear_inode/evict_inode > function. Which might lead into deadlock. > > For further details > https://bugzilla.kernel.org/show_bug.cgi?id=30702 > http://marc.info/?l=linux-mm&m=128942194520631&w=4 > > The patch passes the gfp allocation flag all the way down to those > allocating functions. > You're going to run into trouble by hard-wiring __GFP_REPEAT into all of the pte allocations because if GFP_NOFS is used then direct reclaim will usually fail (see the comment for do_try_to_free_pages(): If the caller is !__GFP_FS then the probability of a failure is reasonably high) and, if it does so continuously, then the page allocator will loop forever. This bit should probably be moved a level higher in your architecture changes to the caller passing GFP_KERNEL. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>