Messages in this thread | | | Date | Tue, 17 Dec 2013 17:31:33 +0800 | From | Li Wang <> | Subject | Re: [PATCH 0/5] VFS: Directory level cache cleaning |
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This extension is just add-on extension. The original debugging capability is still there, and more flexible debugging is now allowed.
On 2013/12/17 17:12, 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. > > commit 9d0243bca345d5ce25d3f4b74b7facb3a6df1232 > Author: Andrew Morton <akpm@osdl.org> > 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 >
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