On 11/30/2011 07:15 AM, Takuya Yoshikawa wrote: > (2011/11/30 14:02), Takuya Yoshikawa wrote: > >> IIUC, even though O(1) is O(1) at the timing of GET DIRTY LOG, it >> needs O(N) write >> protections with respect to the total number of dirty pages: >> distributed, but >> actually each page fault, which should be logged, does some write >> protection? > > Sorry, was not precise. It depends on the level, and not completely > distributed. > But I think it is O(N), and the total number of costs will not change > so much, > I guess. That's true. But some applications do require low latency, and the current code can impose a lot of time with the mmu spinlock held. The total amount of work actually increases slightly, from O(N) to O(N log N), but since the tree is so wide, the overhead is small. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
