On Mon, Apr 24, 2006 at 10:48:32AM -0700, Mingming Cao wrote: > On Fri, 2006-04-21 at 15:09 -0700, Andrew Morton wrote: > > > > > I think it would be saner to explicitly specify the size of the field. > > That means using s32 and s64 throughout this code. > > > > Agree. Will use s64 in this code. As s32 has the same issue with what we > have(unsigned long) on 32 bit machine today: it is not enough for ext3 > to support more than 2**31 free blocks, and also obviously not enough > for 64 bit ext3 that Laurent is working on. I think Andrew's suggestion was to change global counter to s64 and local counter to s32. That way we avoid allocating a 64 bit local counter on 64 bit systems when we could do with a 32 bit counter. (although there is no real space savings with current alloc_percpu ;), but hopefully that will change in the future) > > I looked at the all users of percpu counter that are currently in > mainline(2.6.17-rc1) and in mm tree(2.6.17-rc1-mm2), they are: > > 1. ext2 free blocks/inodes/dirs > (int type, to be changed to unsinged long) > 2. ext3 free blocks/inodes/dirs > (int type, changing to unsigned long or unsigned long long) > 3. nr_files > (currently int type) > 4. decnet_memory allocated > (was atomic_t type in mainline, changed to percpu counter type in mm) > 5. tcp_memory allocated > (was atomic_t type, changed to percpu counter type in mm tree) > > I could be wrong, but I think there will be no effect to change the size > of the global counter from "long" to s64 for above percpu counter users, > except gives the counter more room to grow. Kiran, what do you think? Agree. Since the counters were earlier int/atomic_t, s32 on local and s64 on global should be OK. > Did I miss any other users of the perpcu counters? No, AFAIK, these are the only users as of now. Thanks, Kiran - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
