On Fri, Apr 30, 2010 at 12:43:29PM -0700, Andrew Morton wrote: > > Maybe that fs shouldn't be calling write_cache_pages() at all. After > all, write_cache_pages() is a wrapper which emits a sequence of calls > to ->writepage(), and ->writepage() writes a page. On my todo list is to fix ext4 to not call write_cache_pages() at all. We are seriously abusing that function ATM, since we're not actually writing the pages when we call write_cache_pages(). I won't go into what we're doing, because it's too embarassing, but suffice it to say that we end up calling pagevec_lookup() or pagevec_lookup_tag() *four*, count them *four* times while trying to do writeback. I have a simple patch that gives ext4 our own copy of write_cache_pages(), and then simplifies it a lot, and fixes a bunch of problems, but then I discarded it in favor of fundamentally redoing how we do writeback at all, but it's going to take a while to get things completely right. But I am working to try to fix this. If it would help, I can ressurect the "fork write_cache_pages() and simplify" patch, so ext4 isn't dependent on the mm/page-writeback.c's write_cache_pages(), if there is an immediate, short-term need to fix that function. - Ted -- 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
