On Tue, May 23, 2017 at 08:39:11AM +0200, Michal Hocko wrote: >On Tue 23-05-17 11:27:05, Wei Yang wrote: >> On Thu, May 18, 2017 at 11:06:37AM +0200, Michal Hocko wrote: >> >On Wed 17-05-17 22:11:40, Wei Yang wrote: >> >> This patch serial could be divided into two parts. >> >> >> >> First three patches refine and adds slab sysfs. >> >> Second three patches rename slab sysfs. >> >> >> >> 1. Refine slab sysfs >> >> >> >> There are four level slabs: >> >> >> >> CPU >> >> CPU_PARTIAL >> >> PARTIAL >> >> FULL >> >> >> >> And in sysfs, it use show_slab_objects() and cpu_partial_slabs_show() to >> >> reflect the statistics. >> >> >> >> In patch 2, it splits some function in show_slab_objects() which makes sure >> >> only cpu_partial_slabs_show() covers statistics for CPU_PARTIAL slabs. >> >> >> >> After doing so, it would be more clear that show_slab_objects() has totally 9 >> >> statistic combinations for three level of slabs. Each slab has three cases >> >> statistic. >> >> >> >> slabs >> >> objects >> >> total_objects >> >> >> >> And when we look at current implementation, some of them are missing. So patch >> >> 2 & 3 add them up. >> >> >> >> 2. Rename sysfs >> >> >> >> The slab statistics in sysfs are >> >> >> >> slabs >> >> objects >> >> total_objects >> >> cpu_slabs >> >> partial >> >> partial_objects >> >> cpu_partial_slabs >> >> >> >> which is a little bit hard for users to understand. The second three patches >> >> rename sysfs file in this pattern. >> >> >> >> xxx_slabs[[_total]_objects] >> >> >> >> Finally it looks Like >> >> >> >> slabs >> >> slabs_objects >> >> slabs_total_objects >> >> cpu_slabs >> >> cpu_slabs_objects >> >> cpu_slabs_total_objects >> >> partial_slabs >> >> partial_slabs_objects >> >> partial_slabs_total_objects >> >> cpu_partial_slabs >> > >> >_Why_ do we need all this? >> >> To have a clear statistics for each slab level. > >Is this worth risking breakage of the userspace which consume this data >now? Do you have any user space code which will greatly benefit from the >new data and which couldn't do the same with the current format/output? > >If yes this all should be in the changelog. The answer is no. I have the same concern as yours. So this patch set could be divided into two parts: 1. add some new entry with current name convention, 2. change the name convention. If there are many userspace tools use these entries, the changing is really risky, I agree. Hmm, I still send this out, since current name convention is a little difficult for users to understand, especially after we have several levels slabs. Is it possible to use the name convention I proposed and add link to them to keep the userspace interface? And the second part is to fully utilize current functions. In function show_slab_objects(), we have 9 combinations of slab statistics. 3 for each slab level. And currently code just enable 6 of them. So the first three tries to enable the missing 3 to make it a more complete statistics. BTW, I found we don't have any entry for full slabs statistics. Not sure this is omitted intendedly or not. If the community agrees, I still have a path to enable the statistics for full slabs. Thanks for your comments~ Michal > >-- >Michal Hocko >SUSE Labs -- Wei Yang Help you, Help me
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