Re: [patch -mm] cpusets: add memory_slab_hardwall flag

[KOSAKI Motohiro]

> Adds a per-cpuset `memory_slab_hardwall' flag.
> 
> The slab allocator interface for determining whether an object is allowed
> is
> 
> 	int current_cpuset_object_allowed(int node, gfp_t flags)
> 
> This returns non-zero when the object is allowed, either because
> current's cpuset does not have memory_slab_hardwall enabled or because
> it allows allocation on the node.  Otherwise, it returns zero.
> 
> This interface is lockless because a task's cpuset can always be safely
> dereferenced atomically.
> 
> For slab, if the physical node id of the cpu cache is not from an
> allowable node, the allocation will fail.  If an allocation is targeted
> for a node that is not allowed, we allocate from an appropriate one
> instead of failing.
> 
> For slob, if the page from the slob list is not from an allowable node,
> we continue to scan for an appropriate slab.  If none can be used, a new
> slab is allocated.
> 
> For slub, if the cpu slab is not from an allowable node, the partial list
> is scanned for a replacement.  If none can be used, a new slab is
> allocated.

Hmmm,
this description only explay how to implement this.
but no explain why this patch is useful.

Could you please who and why need it?



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/