On Tue, Jun 15, 2010 at 03:13:09PM -0400, Rik van Riel wrote: > On 06/15/2010 12:54 PM, Christoph Hellwig wrote: > >On Tue, Jun 15, 2010 at 12:49:49PM -0400, Rik van Riel wrote: > >>This is already in a filesystem. Why does ->writepage get > >>called a second time? Shouldn't this have a gfp_mask > >>without __GFP_FS set? > > > >Why would it? GFP_NOFS is not for all filesystem code, but only for > >code where we can't re-enter the filesystem due to deadlock potential. > > Why? How about because you know the stack is not big enough > to have the XFS call path on it twice? :) > > Isn't the whole purpose of this patch series to prevent writepage > from being called by the VM, when invoked from a deep callstack > like xfs writepage? > > That sounds a lot like simply wanting to not have GFP_FS... buffered write path uses __GFP_FS by design because huge amounts of (dirty) memory can be allocated in doing pagecache writes. If would be nasty if that was not allowed to wait for filesystem activity. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>