[BUGFIX][PATCH] memcg: avoid use cmpxchg in swap cgroup maintainance (Was Re: 34-rc1-git3 build failure with CGROUP_MEM_RES_CTLR_SWAP=y

[Balbir Singh]

* KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com> [2010-03-15 10:02:02]:

> On Sun, 14 Mar 2010 16:18:06 +0530
> Sachin Sant <sachinp at in.ibm.com> wrote:
> 
> > On a PowerPC box, latest 34-rc1 git(d89b218b8...) fails to build
> > with CGROUPS_MEM_RES_CTRL_SWAP=y. 
> > 
> > LD      init/built-in.o
> > LD      .tmp_vmlinux1
> > mm/built-in.o: In function __xchg:
> > arch/powerpc/include/asm/system.h:331: undefined reference to .__xchg_called_with_bad_pointer
> > mm/built-in.o: In function __cmpxchg:
> > arch/powerpc/include/asm/system.h:474: undefined reference to .__cmpxchg_called_with_bad_pointer
> > make: *** [.tmp_vmlinux1] Error 1
> > 
> > The code in question was added via commit 024914477e...
> > 
> > memcg: move charges of anonymous swap
> > 
> Oh..ok, powerpc (and other archs?) can't do 2byte cmpxchg and xchg.
> Then, we should use spinlock rather than that.
> 
> How about this ? Nishimura-san, could you consider something better ?
> We need a quick fix.
>

Looks good to me

 
Acked-by: Balbir Singh <balbir at linux.vnet.ibm.com>
 

-- 
	Three Cheers,
	Balbir