On Wed, Mar 16, 2011 at 05:35:10PM +0100, Johannes Weiner wrote: [..] > > IIUC, this sounds more like a solution to quickly come up with a list of > > inodes one should be writting back. One could also come up with this kind of > > list by going through memcg->lru list also (approximate). So this can be > > an improvement over going through memcg->lru instead go through > > memcg->mapping_list. > > Well, if you operate on a large file it may make a difference between > taking five inodes off the list and crawling through hundreds of > thousands of pages to get to those same five inodes. > > And having efficient inode lookup for a memcg makes targetted > background writeback more feasible: pass the memcg in the background > writeback work and have the flusher go through memcg->mappings, > selecting those that match the bdi. > > Am I missing something? I feel like I missed your point. No. Thanks for the explanation. I get it. Walking through the memcg->lru list to figure out inodes memcg is writting to will be slow and can be very painful for large files. Keeping a more direct mapping like memcg_mapping list per memcg can simplify it a lot. Thanks Vivek -- 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>