On 2012-06-18, at 6:08 AM, Christoph Hellwig wrote: > May saw the release of Linux 3.4, including a decent sized XFS update. > Remarkable XFS features in Linux 3.4 include moving over all metadata > updates to use transactions, the addition of a work queue for the > low-level allocator code to avoid stack overflows due to extreme stack > use in the Linux VM/VFS call chain, This is essentially a workaround for too-small stacks in the kernel, which we've had to do at times as well, by doing work in a separate thread (with a new stack) and waiting for the results? This is a generic problem that any reasonably-complex filesystem will have when running under memory pressure on a complex storage stack (e.g. LVM + iSCSI), but causes unnecessary context switching. Any thoughts on a better way to handle this, or will there continue to be a 4kB stack limit and hack around this with repeated kmalloc on callpaths for any struct over a few tens of bytes, implementing memory pools all over the place, and "forking" over to other threads to continue the stack consumption for another 4kB to work around the small stack limit? Cheers, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
