On Wed, 8 Oct 2008 23:00:54 -0400 Theodore Tso <tytso@xxxxxxx> wrote: > On Thu, Oct 02, 2008 at 10:24:38PM -0700, Andrew Morton wrote: > > > > Mount a junk partition with `-oakpm' and run some benchmarks. If the > > results are "wow" then it's worth spending time on. If the results are > > "meh" then we can not bother.. > > > > I've ported the patch to the ext4 filesystem, and dropped it into the > unstable portion of the ext4 patch queue. Useful, thanks. > If we can get someone (hi, > Ric!) to run fs_mark with and without -o akpm_lock_hack, I suspect we > will find that it makes quite a large difference on that particular > benchmark, since it is fsync-heavy to force a large number of > transaction, and the creation of the inodes should cause multiple > blocks that will be entangled between the current and committing > transactions. > fsync? Yes, I suppose so. Repeated modifications to the same inodes/directories/bitmaps blocks/etc will hurt. A quick test on other quantified workloads would be useful too. If the results look promising then someone(tm) will need to work out how to fix this for real. > > ext4: akpm's locking hack to fix locking delays > > This is a port of the following patch from Andrew Morton to ext4: > > http://lkml.org/lkml/2008/10/3/22 > > This fixes a major contention problem in do_get_write_access() when a > buffer is modified in both the current and committing transaction. More specifically: "under checkpoint writeback in the committing transaction when the committing transaction requests write access". -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
