Messages in this thread | | | Date | Wed, 31 Oct 2007 22:25:10 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [RFC] cpuset relative memory policies - second choice |
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On Wed, 31 Oct 2007, Paul Jackson wrote:
> Christoph, replying to pj: > > > Well, the mpol_nodemask_mode already is char. So I guess you're > > > asking if we should change 'policy' to type char as well. > > > > Right. > > Ok - but why? > > I don't see that it matters whether policy is short or char.
It looks strange if they have different. Maybe use u8 for both?
> > s/numactl/libnuma/ > > So you would rather have libnuma manage this flag? > > As opposed to what else managing it? I'm still a tad confused on > what you're suggesting on this one.
You are managing it in the task struct. No need to. libnuma can handle it.
> > But that is only done in libnuma. User code does not call this directly. > > I disagree. > > There are several mempolicy interfaces in use, including at least: > 1) libnuma, which in turn is based on (5), below > 2) the numactl command line utility (based on libnuma) > 3) libcpuset (which has its own modest mempolicy interface)
These are no problem 1/2 are libnuma. No current version of libcpuset is available.
> 4) the glibc mbind/set_mempolicy/get_mempolicy wrappers, in C code > 5) roll your own mbind/*_mempolicy system call wrappers, in C code
Those exist? Never seen that.
> With the mode bit as in my patch, there are fewer places in the user > code that have to be gotten just right. With your way, each and > every mbind and *_mempolicy call has to be hacked with the new flag > if one is going to use the new nodemask bit numbering. Some of these
Yes and that makes sure it is thought through and done right.
> Perhaps that's the way to go: > mbind2, get_mempolicy2, and set_mempolicy2.
That would be okay from the backwards compat standpoint. - 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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