On Tue, 19 May 2020 13:45:45 -0700 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > On Tue, May 19, 2020 at 10:19:06PM +0200, Sebastian Andrzej Siewior wrote: > > The radix-tree and idr preload mechanisms use preempt_disable() to protect > > the complete operation between xxx_preload() and xxx_preload_end(). > > > > As the code inside the preempt disabled section acquires regular spinlocks, > > which are converted to 'sleeping' spinlocks on a PREEMPT_RT kernel and > > eventually calls into a memory allocator, this conflicts with the RT > > semantics. > > > > Convert it to a local_lock which allows RT kernels to substitute them with > > a real per CPU lock. On non RT kernels this maps to preempt_disable() as > > before, but provides also lockdep coverage of the critical region. > > No functional change. > > I don't seem to have a locallock.h in my tree. Where can I find more > information about it? PATCH 1 ;-) https://lore.kernel.org/r/20200519201912.1564477-1-bigeasy@xxxxxxxxxxxxx With lore and b4, it should now be easy to get full patch series. -- Steve > > > +++ b/lib/radix-tree.c > > @@ -20,6 +20,7 @@ > > #include <linux/kernel.h> > > #include <linux/kmemleak.h> > > #include <linux/percpu.h> > > +#include <linux/locallock.h> > > #include <linux/preempt.h> /* in_interrupt() */ > > #include <linux/radix-tree.h> > > #include <linux/rcupdate.h>
