On Tue 17-12-13 17:12:52, Li Zefan wrote: > On 2013/12/17 15:23, Li Wang wrote: > > If we do wanna equip fadvise() with directory level page cache cleaning, > > this could be solved by invoking (inode_permission() || capable(CAP_SYS_ADMIN)) before manipulating the page cache of that inode. > > We think the current extension to 'drop_caches' has a complete back > > compatibility, the old semantics keep unchanged, and with add-on > > features to do finer granularity cache cleaning should be also > > desirable. > > > > I don't think you can extend the drop_caches interface this way. It should > be used for debuging only. Completely agreed. The interface shouldn't be further extended. I would even argue it shouldn't be used in the first place. > commit 9d0243bca345d5ce25d3f4b74b7facb3a6df1232 > Author: Andrew Morton <akpm@xxxxxxxx> > Date: Sun Jan 8 01:00:39 2006 -0800 > > [PATCH] drop-pagecache > > Add /proc/sys/vm/drop_caches. When written to, this will cause the kernel to > discard as much pagecache and/or reclaimable slab objects as it can. THis > operation requires root permissions. > > ... > > This is a debugging feature: useful for getting consistent results between > filesystem benchmarks. We could possibly put it under a config option, but > it's less than 300 bytes. > > Also see http://lkml.org/lkml/2013/7/26/230 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>