On Tue, Feb 25, 2014 at 10:16:20AM +1100, Dave Chinner wrote: > On Mon, Feb 24, 2014 at 03:43:05PM -0500, Brian Foster wrote: > > On Mon, Feb 24, 2014 at 05:29:24PM +1100, Dave Chinner wrote: > > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > > > The same code is repeated in different places to set up > > > multithreaded prefetching. This can all be factored into a single > > > implementation. > > > > > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > .... > > > static void > > > traverse_ags( > > > - xfs_mount_t *mp) > > > + struct xfs_mount *mp) > > > { > > > - int i; > > > - work_queue_t queue; > > > - prefetch_args_t *pf_args[2]; > > > - > > > - /* > > > - * we always do prefetch for phase 6 as it will fill in the gaps > > > - * not read during phase 3 prefetch. > > > - */ > > > - queue.mp = mp; > > > - pf_args[0] = start_inode_prefetch(0, 1, NULL); > > > - for (i = 0; i < glob_agcount; i++) { > > > - pf_args[(~i) & 1] = start_inode_prefetch(i + 1, 1, > > > - pf_args[i & 1]); > > > - traverse_function(&queue, i, pf_args[i & 1]); > > > - } > > > + do_inode_prefetch(mp, 0, traverse_function, true, true); > > > > The cover letter indicates the parallelization of phase 6 was dropped, > > but this appears to (conditionally) enable it. > > No, it enables prefetch, it does not enable threading. The second > parameter is "0" which means that do_inode_prefetch() executes the > single threaded prefetch walk like the above code. i.e.: > > > > + */ > > > +void > > > +do_inode_prefetch( > > > + struct xfs_mount *mp, > > > + int stride, > > stride = 0 > > > > + void (*func)(struct work_queue *, > > > + xfs_agnumber_t, void *), > > > + bool check_cache, > > > + bool dirs_only) > > > +{ > > > + int i, j; > > > + xfs_agnumber_t agno; > > > + struct work_queue queue; > > > + struct work_queue *queues; > > > + struct prefetch_args *pf_args[2]; > > > + > > > + /* > > > + * If the previous phases of repair have not overflowed the buffer > > > + * cache, then we don't need to re-read any of the metadata in the > > > + * filesystem - it's all in the cache. In that case, run a thread per > > > + * CPU to maximise parallelism of the queue to be processed. > > > + */ > > > + if (check_cache && !libxfs_bcache_overflowed()) { > > > + queue.mp = mp; > > > + create_work_queue(&queue, mp, libxfs_nproc()); > > > + for (i = 0; i < mp->m_sb.sb_agcount; i++) > > > + queue_work(&queue, func, i, NULL); > > > + destroy_work_queue(&queue); > > > + return; > > > + } > > > + > > > + /* > > > + * single threaded behaviour - single prefetch thread, processed > > > + * directly after each AG is queued. > > > + */ > > > + if (!stride) { > > > + queue.mp = mp; > > > + pf_args[0] = start_inode_prefetch(0, dirs_only, NULL); > > > + for (i = 0; i < mp->m_sb.sb_agcount; i++) { > > > + pf_args[(~i) & 1] = start_inode_prefetch(i + 1, > > > + dirs_only, pf_args[i & 1]); > > > + func(&queue, i, pf_args[i & 1]); > > > + } > > > + return; > > > + } > > So we run this "!stride" code. Hmmmm - maybe you are commenting on > the "check_cache" code? I probably should prevent that from > triggering, too. > Sorry, I could have been more clear on that. Yes, I'm referring specifically to setting check_cache to true. Brian > Cheers, > > Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs