On Tue, Mar 08, 2011 at 07:31:56PM -0500, Stephen Wilson wrote: > > Morally, the question of whether an address lies in a gate vma should be asked > with respect to an mm, not a particular task. > > Practically, dropping the dependency on task_struct will help make current and > future operations on mm's more flexible and convenient. In particular, it > allows some code paths to avoid the need to hold task_lock. > > The only architecture this change impacts in any significant way is x86_64. > The principle change on that architecture is to mirror TIF_IA32 via > a new flag in mm_context_t. The problem is -- you're adding a likely cache miss on mm_struct for every 32bit compat syscall now, even if they don't need mm_struct currently (and a lot of them do not) Unless there's a very good justification to make up for this performance issue elsewhere (including numbers) this seems like a bad idea. > This is the first of a two part series that implements safe writes to > /proc/pid/mem. I will be posting the second series to lkml shortly. These Making every syscall slower for /proc/pid/mem doesn't seem like a good tradeoff to me. Please solve this in some other way. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>