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2017-01-12genirq/affinity: Fix node generation from cpumaskGuilherme G. Piccoli
commit c0af52437254fda8b0cdbaae5a9b6d9327f1fcd5 upstream. Commit 34c3d9819fda ("genirq/affinity: Provide smarter irq spreading infrastructure") introduced a better IRQ spreading mechanism, taking account of the available NUMA nodes in the machine. Problem is that the algorithm of retrieving the nodemask iterates "linearly" based on the number of online nodes - some architectures present non-linear node distribution among the nodemask, like PowerPC. If this is the case, the algorithm lead to a wrong node count number and therefore to a bad/incomplete IRQ affinity distribution. For example, this problem were found in a machine with 128 CPUs and two nodes, namely nodes 0 and 8 (instead of 0 and 1, if it was linearly distributed). This led to a wrong affinity distribution which then led to a bad mq allocation for nvme driver. Finally, we take the opportunity to fix a comment regarding the affinity distribution when we have _more_ nodes than vectors. Fixes: 34c3d9819fda ("genirq/affinity: Provide smarter irq spreading infrastructure") Reported-by: Gabriel Krisman Bertazi <gabriel@krisman.be> Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Cc: linux-pci@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: hch@lst.de Link: http://lkml.kernel.org/r/1481738472-2671-1-git-send-email-gpiccoli@linux.vnet.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-14genirq/affinity: Remove old irq spread infrastructureThomas Gleixner
No more users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: axboe@fb.com Cc: keith.busch@intel.com Cc: agordeev@redhat.com Cc: linux-block@vger.kernel.org Link: http://lkml.kernel.org/r/1473862739-15032-5-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-09-14genirq/affinity: Provide smarter irq spreading infrastructureThomas Gleixner
The current irq spreading infrastructure is just looking at a cpumask and tries to spread the interrupts over the mask. Thats suboptimal as it does not take numa nodes into account. Change the logic so the interrupts are spread across numa nodes and inside the nodes. If there are more cpus than vectors per node, then we set the affinity to several cpus. If HT siblings are available we take that into account and try to set all siblings to a single vector. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: axboe@fb.com Cc: keith.busch@intel.com Cc: agordeev@redhat.com Cc: linux-block@vger.kernel.org Link: http://lkml.kernel.org/r/1473862739-15032-3-git-send-email-hch@lst.de
2016-08-22genirq/affinity: Use get/put_online_cpus around cpumask operationsChristoph Hellwig
Without locking out CPU mask operations we might end up with an inconsistent view of the cpumask in the function. Fixes: 5e385a6ef31f: "genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors" Signed-off-by: Christoph Hellwig <hch@lst.de> Link: http://lkml.kernel.org/r/1470924405-25728-1-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-07-04genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectorsChristoph Hellwig
This is lifted from the blk-mq code and adopted to use the affinity mask concept just introduced in the irq handling code. It tries to keep the algorithm the same as the one current used by blk-mq, but improvements like assining vectors on a per-node basis instead of just per sibling are possible with this simple move and refactoring. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-7-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>