On Wed, 13 Sep 2017 18:44:11 -0400 Sherry Yang <sher...@android.com> wrote:
> On Wed, Sep 13, 2017 at 6:09 PM, Andrew Morton > <a...@linux-foundation.org> wrote: > > On Wed, 13 Sep 2017 17:59:27 -0400 Sherry Yang <sher...@android.com> wrote: > > > >> Restore asynchronous mmput, allowing mmput_async to be called > >> from an atomic context in Android binder shrinker callback. > >> > >> mmput_async was initially introduced in ec8d7c14e > >> ("mm, oom_reaper: do not mmput synchronously from the > >> oom reaper context"), and was removed in 212925802 > >> ("mm: oom: let oom_reap_task and exit_mmap run concurrently") > > > > Presumably there's a patch somewhere which adds a call to mmput_async() > > into drivers/android/binder.c? Where is that patch? > > The patch that uses mmput_async() is > https://lkml.org/lkml/2017/9/8/785. Gmail doesn't seem to respect > in-reply-to. (Top-posting repaired. Please don't!) Is it necessary for binder_alloc_free_page() to take a ref on the mm? As long as alloc->tsk doesn't exit during binder_alloc_free_page()'s execution, that task's reference on the mm should be sufficient to keep the mm alive?