Messages in this thread | | | Date | Mon, 9 Mar 2009 13:13:06 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [patch -mm] cpusets: add memory_slab_hardwall flag |
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On Mon, 9 Mar 2009, Christoph Lameter wrote:
> Again these are fastpath modifications. >
The nature of the change requires the logic to be placed in the fastpath to determine whether a cpu slab's node is allowed by the allocating task's cpuset.
You have previously stated that you would prefer that this feature be tunable from userspace. This patch adds the `memory_slab_hardwall' cpuset flag which defaults to off.
> Scanning the partial list for matching nodes is an expensive operation. >
It depends on how long you scan for a matching node, but again: this should be assumed by the user if the option has been enabled.
> Adding RCU into the fast paths is also another big worry. >
This could be mitigated by adding a PF_SLAB_HARDWALL flag similiar to PF_SPREAD_PAGE and PF_SPREAD_SLAB. I'd prefer not to add additional cpuset-specific task flags, but this would address your concern.
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