On Thu, 2007-06-28 at 10:39 +1000, David Chinner wrote: > > > I don't think it does - swapfile I/O looks like it goes direct to > bio without passing through the filesystem. When the swapfile is > mapped, it scans and records the extent map of the entire swapfile > in a separate structure and AFAICT the swap code uses that built map > without touching the filesystem at all. > > If that is true then the written/unwritten state of the extents is > irrelevant; all we need is allocated disk space for the file and > swapping should work. And it's not like anyone should be reading > the contents of that swapfile through the filesystem, either. ;) Ah, yes, good point - thats true. Unwritten extents are ideal for this then, as attempts to read swap via the regular interfaces will return zeros instead of random swapped out memory contents. cheers. - 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
