On Thu, 12 Apr 2018, Matthew Wilcox wrote: > > Thus the next invocation of the fastpath will find that c->freelist is > > NULL and go to the slowpath. ... > > _ah_. I hadn't figured out that c->page was always NULL in the debugging > case too, so ___slab_alloc() always hits the 'new_slab' case. Thanks! Also note that you can have SLUB also do the build with all debugging on without having to use a command like parameter (like SLAB). That requires CONFIG_SLUB_DEBUG_ON to be set. CONFIG_SLUB_DEBUG is set by default for all distro builds. It only includes the debug code but does not activate them by default. Kernel command line parameters allow you to selectively switch on debugging features for specific slab caches so that you can limit the latency variations introduced by debugging into the production kernel. Thus subtle races may be found.
