Messages in this thread |  | | Date | Tue, 17 Jun 2008 09:10:38 +0530 | From | Balbir Singh <> | Subject | Re: [PATCH 1/2] memcg: res counter set limit |
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KAMEZAWA Hiroyuki wrote: > Helper function of res_counter for reducing usage in subsys(memcg). > > Changelog xxx -> v5. > - new file. > > Background: > In v3, I was asked to implement generic ones to res_counter. > In v4. I was asked not to implement generic ones because memcg is only > controller which can reduce usage by the kernel. Okay, maybe make sense. > In this version, adds only necessary helpers to res_counter in > not-invasive manner. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > --- > include/linux/res_counter.h | 7 +++++++ > kernel/res_counter.c | 24 ++++++++++++++++++++++++ > 2 files changed, 31 insertions(+) > > Index: mm-2.6.26-rc5-mm3/include/linux/res_counter.h > =================================================================== > --- mm-2.6.26-rc5-mm3.orig/include/linux/res_counter.h > +++ mm-2.6.26-rc5-mm3/include/linux/res_counter.h > @@ -136,6 +136,12 @@ static inline bool res_counter_check_und > return ret; > } > > +/* > + * set new limit to the val. if usage > val, returns -EBUSY. > + * returns 0 at success. > + */ > +int res_counter_set_limit(struct res_counter *cnt, unsigned long long limit); > + > static inline void res_counter_reset_max(struct res_counter *cnt) > { > unsigned long flags; > @@ -153,4 +159,5 @@ static inline void res_counter_reset_fai > cnt->failcnt = 0; > spin_unlock_irqrestore(&cnt->lock, flags); > } > +
I don't understand this extra newline here
> #endif > Index: mm-2.6.26-rc5-mm3/kernel/res_counter.c > =================================================================== > --- mm-2.6.26-rc5-mm3.orig/kernel/res_counter.c > +++ mm-2.6.26-rc5-mm3/kernel/res_counter.c > @@ -143,3 +143,27 @@ out_free: > out: > return ret; > } > + > + > +/** > + * res_counter_set_limit - set limit of res_counter. > + * @cnt: the res_counter > + * @limit: the new limit > + * > + * Note that res_coutner_write() allows the same kind of operation. > + * But this returns -EBUSY when new limit < usage. If you want strict control > + * of limit, please use this. > + */ > +int res_counter_set_limit(struct res_counter *cnt, unsigned long long limit) > +{ > + unsigned long flags; > + int ret = -EBUSY; > + > + spin_lock_irqsave(&cnt->lock, flags); > + if (cnt->usage <= limit) { > + cnt->limit = limit; > + ret = 0; > + } > + spin_unlock_irqrestore(&cnt->lock, flags); > + return ret; > +}
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
-- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL
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