Messages in this thread | | | Date | Fri, 17 Apr 2015 06:32:04 -0700 | From | Guenter Roeck <> | Subject | Re: Upstream kernel fails to run on qemu-sparc64 due to commit 889fa31f0 (blk-mq: reduce unnecessary software queue looping) |
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On Thu, Apr 16, 2015 at 11:32:20PM -0700, Guenter Roeck wrote: > Hi, > > my qemu-sparc64 tests fail to run with kernel v4.0-7245-ga39ef1a7c609. > Bisect points to commit 889fa31f00b ("blk-mq: reduce unnecessary software > queue looping"). Reverting this commit fixes the problem. > > I had a look into the commit, but I have no idea what might be wrong. > > I made the bisect log, images, configuration file, root file system, and directions > on how to run the images available at http://server.roeck-us.net/qemu/sparc64. > > Please let me know if there is any other information I can provide. > As additional information:
+ * Set the map size to the number of mapped software queues. + * This is more accurate and more efficient than looping + * over all possibly mapped software queues. + */ + map->map_size = hctx->nr_ctx / map->bits_per_word;
On my system, hctx->nr_ctx is 1, and map->bits_per_word is 8. Thus map->map_size is set to 0, which doesn't make much sense. The system comes up if I replace the above code with map->map_size = DIV_ROUND_UP(hctx->nr_ctx, map->bits_per_word);
I have no idea if that is the correct fix, though.
Guenter
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