Messages in this thread | | | From | Justin TerAvest <> | Date | Wed, 23 Mar 2011 10:21:01 -0700 | Subject | Re: [PATCH v2 2/8] block,fs,mm: IO cgroup tracking for buffered write |
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On Tue, Mar 22, 2011 at 9:52 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > On Tue, 22 Mar 2011 16:08:49 -0700 > Justin TerAvest <teravest@google.com> wrote: > >> +static inline void page_cgroup_set_blkio_id(struct page_cgroup *pc, >> + unsigned long id) >> +{ >> + unsigned long old, new, prev; >> + >> + /* pc->flags isn't lock protected, so we must cmpxchg. */ >> + WARN_ON(id >= (1UL << PAGE_TRACKING_ID_BITS)); >> + do { >> + new = old = pc->flags; >> + new &= (1UL << PAGE_TRACKING_ID_SHIFT) - 1; >> + new |= (unsigned long)(id << PAGE_TRACKING_ID_SHIFT); >> + prev = cmpxchg(&pc->flags, old, new); >> + } while (prev != old); > > How to support archs which doesn't have cmpxchg ? > At least, you need take care of compile error.
Hi Kame,
Is there really no generic cmpxchg()? I thought that was what include/asm-generic/cmpxchg-local.h was for.
Thanks, Justin
> > Thanks, > -Kame > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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