On Mon, Feb 18, 2019 at 05:11:45PM +0900, Minchan Kim wrote: > binder has used write-side mmap_sem semaphore to release memory > mapped at address space of the process. However, right lock to > release pages is down_read, not down_write because page table lock > already protects the race for parallel freeing. > > Please do not use mmap_sem write-side lock which is well known > contented lock. > > Cc: Todd Kjos <tk...@google.com> > Cc: Martijn Coenen <m...@android.com> > Cc: Arve Hjønnevåg <a...@android.com> > Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> > Signed-off-by: Minchan Kim <minc...@kernel.org> > --- > drivers/android/binder_alloc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-)
Is this just needed for the recent binder changes that are in linux-next, or for older kernels as well? thanks, greg k-h
