On Tue, 2009-09-08 at 22:16 -0400, Chuck Lever wrote: > On Sep 8, 2009, at 9:37 PM, Trond Myklebust wrote: > > On Tue, 2009-09-08 at 21:01 -0400, Chuck Lever wrote: > >> That is precisely the case here, in fact. The upper file system is > >> attempting to reclaim memory in the same kernel where the NFS client > >> is trying to allocate with GFP_KERNEL. > > > > That's the "upper file system"'s problem, not ours... Stacking > > filesystems causes issues. Screwing over the existing users of the > > underlying filesystem is not a fix for those issues... > > How does this change "screw over" the existing users of NFS O_DIRECT? If they are low on memory, and call read() or write() on an O_DIRECT file, the kernel will fail to start the necessary memory reclaim. Given that by far the most common users of NFS O_DIRECT these days tend to be large databases with rather heavy memory requirements our code changes should rather be moving in the opposite direction w.r.t. use of GFP_NOFS. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
