On Thursday 24 July 2008 20:50, Sebastien Dugue wrote: > From: Sebastien Dugue <sebastien.dugue@xxxxxxxx> > Date: Tue, 22 Jul 2008 11:56:41 +0200 > Subject: [PATCH][RT] powerpc - Make the irq reverse mapping radix tree > lockless > > The radix tree used by interrupt controllers for their irq reverse > mapping (currently only the XICS found on pSeries) have a complex locking > scheme dating back to before the advent of the concurrent radix tree on > preempt-rt. > > Take advantage of this and of the fact that the items of the tree are > pointers to a static array (irq_map) elements which can never go under us > to simplify the locking. > > Concurrency between readers and writers are handled by the intrinsic > properties of the concurrent radix tree. Concurrency between the tree > initialization which is done asynchronously with readers and writers access > is handled via an atomic variable (revmap_trees_allocated) set when the > tree has been initialized and checked before any reader or writer access > just like we used to check for tree.gfp_mask != 0 before. Hmm, RCU radix tree is in mainline too for quite a while. I thought Ben had already converted this code over ages ago... Nothing against the -rt patch, but mainline should probably be updated to use RCU as well? -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
