Thanks a lot for looking at these. On Tue, 31 May 2011, Christoph Hellwig wrote: > > Note that drivers/gpu/drm/i915/i915_gem.c i915_gem_object_truncate() > > calls the tmpfs ->truncate_range directly: update that in a separate > > patch later, for now just let it duplicate the truncate_inode_pages(). > > Because i915 handles unmap_mapping_range() itself at a different stage, > > we have chosen not to bundle that into ->truncate_range. > > In your next series that makes it call the readpae replacement directly > it might be nice to also call directly into shmem for hole punching. (i915 isn't really doing hole-punching there, I think it just found it a useful interface to remove the page-and-swapcache without touching i_size. Parentheses because it makes no difference to your point.) Okay, I'd better do a v2 (probably not before the weekend), and change that around to go explicitly to shmem there as well: I'd rather settle the interfaces to other subsystems in this series, than mix it with the implementation in the next series. When I say "shmem", I am including the !SHMEM-was-TINY_SHMEM case too, which goes to ramfs. Currently i915 has been configured to disable that possibility, though we insisted on it originally: there may or may not be good reason for disabling it - may just be a side-effect of the rather twisted unintuitive SHMEM/TMPFS dependencies. > > > I notice that ext4 is now joining ocfs2 and xfs in supporting fallocate > > FALLOC_FL_PUNCH_HOLE: perhaps they should support truncate_range, and > > tmpfs should support fallocate? But worry about that another time... > > No, truncate_range and the madvice interface are pretty sad hacks that > should never have been added in the first place. Adding > FALLOC_FL_PUNCH_HOLE support for shmem on the other hand might make > some sense. Fine, I'll add tmpfs PUNCH_HOLE later on. And wire up madvise MADV_REMOVE to fallocate PUNCH_HOLE, yes? Would you like me to remove the ->truncate_range method from inode_operations completely? I can do that now, hack directly to tmpfs in the interim, in the same way as for i915. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>