• Linus Torvalds's avatar
    Merge branch 'access-creds' · a29a0a46
    Linus Torvalds authored
    The access() (and faccessat()) credentials change can cause an
    unnecessary load on the RCU machinery because every access() call ends
    up freeing the temporary access credential using RCU.
    
    This isn't really noticeable on small machines, but if you have hundreds
    of cores you can cause huge slowdowns due to RCU storms.
    
    It's easy to avoid: the temporary access crededntials aren't actually
    normally accessed using RCU at all, so we can avoid the whole issue by
    just marking them as such.
    
    * access-creds:
      access: avoid the RCU grace period for the temporary subjective credentials
    a29a0a46
cred.c 23.3 KB