on 03/02/2013 20:42 Andriy Gapon said the following: > - vm_page_busy(pp); > - vm_page_undirty(pp);
ZFS lookup_page previously had two interesting bugs that almost canceled each other. The first bug was that vm_page_undirty was called even if we read from a ZFS-backed page into a user buffer. Obviously this action didn't actually magically make the page clean. The second bug was that vm_page_undirty was called without doing pmap_remove_write() first and so, if the page was actually modified, the modified bit leaked back from a pmap to the dirty bits. So no harm was done. On the other hand, if a ZFS-backed dirty page was over-written with a content from ARC (which was first put there from a userland buffer), then the page stayed marked dirty for all the same reason (lack of pmap_remove_write). And so exactly the same data would have to be re-written to ARC / disk again. -- Andriy Gapon _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
