lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-Id: <1193412644.5032.13.camel@localhost> Date: Fri, 26 Oct 2007 11:30:44 -0400 From: Lee Schermerhorn <Lee.Schermerhorn@...com> To: David Rientjes <rientjes@...gle.com> Cc: Paul Jackson <pj@....com>, Christoph Lameter <clameter@....com>, akpm@...ux-foundation.org, ak@...e.de, linux-kernel@...r.kernel.org Subject: Re: [patch 2/2] cpusets: add interleave_over_allowed option On Thu, 2007-10-25 at 19:11 -0700, David Rientjes wrote: > On Thu, 25 Oct 2007, Paul Jackson wrote: > > > David - could you describe the real world situation in which you > > are finding that this new 'interleave_over_allowed' option, aka > > 'memory_spread_user', is useful? I'm not always opposed to special > > case solutions; but they do usually require special case needs to > > justify them ;). > > > > Yes, when a task with MPOL_INTERLEAVE has its cpuset mems_allowed expanded > to include more memory. The task itself can't access all that memory with > the memory policy of its choice. > > Since the cpuset has changed the mems_allowed of the task without its > knowledge, it would require a constant get_mempolicy() and set_mempolicy() > loop in the application to catch these changes. That's obviously not in > the best interest of anyone. > > So my change allows those tasks that have already expressed the desire to > interleave their memory with MPOL_INTERLEAVE to always use the full range > of memory available that is dynamically changing beneath them as a result > of cpusets. Keep in mind that it is still possible to request an > interleave only over a subset of allowed mems: but you must do it when you > create the interleaved mempolicy after it has been attached to the cpuset. > set_mempolicy() changes are always honored. > > The only other way to support such a feature is through a modification to > mempolicies themselves, which Lee has already proposed. The problem with > that is it requires mempolicy support for cpuset cases and modification to > the set_mempolicy() API. My solution presents a cpuset fix for a cpuset > problem. Actually, my patch doesn't change the set_mempolicy() API at all, it just co-opts a currently unused/illegal value for the nodemask to indicate "all allowed nodes". Again, I need to provide a libnuma API to request this. Soon come, mon... Here's a link the last posting of my patch, as Paul requested: http://marc.info/?l=linux-mm&m=118849999128086&w=4 A bit out of date, but I'll fix that maybe next week. Lee <snip> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists