On Mon, May 19, 2008 at 09:44:11AM -0700, Christoph Lameter wrote: > On Mon, 19 May 2008, David Chinner wrote: > > > Defragmentation is triggered as part of the usual memory reclaim > > process. Which implies we've run out of free memory, correct? > > Yes but we have already reclaimed some memory. > > > > How do you trigger such a special writeout? > > > > filemap_fdatawrite_range() perhaps? > > Could you provide me such a patch? I would not know how much to writeout. > If we had such a method then we could also use that for the swap case > where we also write out single pages? How hard is it? I don't have time right now to do this, but it's essentially: mapping = page->mapping; ...... - mapping->aops->writepage(); + filemap_fdatawrite_range(mapping, start, end); Where [start,end] span page->index and are is large enough to get a substantial sized I/O to disk (say at least SWAP_CLUSTER_MAX pages, preferrably larger for 4k page size machines). Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group -- 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
