Thank you all for replying back. > > Hold this ... while the patch is correct, Peter raised > a valid concern about its usefulness, which should be > sorted out first. > Can't the shmctl(SHM_LOCK) system call be called for a huge number of usermode processes ? Other place from where usr_shm_lock() is called is for hugetlb from shmget(SHM_HUGETLB) system call via ipc_get(). As far as users are concerned, I think that if even 2 user_structs encounter this on 2 different CPUs, why should the processors waste any time at all at looping even once if they belong to different user_structs ? I totally agree with you that maybe if we look at the entire workloads it probably wouldn't matter much because of low number of users, but why should the CPUs compete and spin for different users at all when nothing global is affected ? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>