On Thu, May 16, 2024 at 12:10:44AM +0200, Jan Kara wrote: > From: Mikulas Patocka <mpatocka@xxxxxxxxxx> > > I have a program that sets up a periodic timer with 10ms interval. When > the program attempts to call fallocate(2) on tmpfs, it goes into an > infinite loop. fallocate(2) takes longer than 10ms, so it gets > interrupted by a signal and it returns EINTR. On EINTR, the fallocate > call is restarted, going into the same loop again. > > Let's change the signal_pending() check in shmem_fallocate() loop to > fatal_signal_pending(). This solves the problem of shmem_fallocate() > constantly restarting. Since most other filesystem's fallocate methods > don't react to signals, it is unlikely userspace really relies on timely > delivery of non-fatal signals while fallocate is running. Also the > comment before the signal check: > > /* > * Good, the fallocate(2) manpage permits EINTR: we may have > * been interrupted because we are using up too much memory. > */ > > indicates that the check was mainly added for OOM situations in which > case the process will be sent a fatal signal so this change preserves > the behavior in OOM situations. > > [JK: Update changelog and comment based on upstream discussion] > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> > Signed-off-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
