Le samedi 16 octobre 2010 Ã 21:04 +1100, Dave Chinner a Ãcrit : > get_nr_inodes_unused() is called on every single shrinker call. i.e. > for every 128 inodes we attempt to reclaim. Given that I'm seeing > inode reclaim rate in the order of a million per second on a 8p box, > that meets your criteria for using the generic percpu counter > infrastructure. > > Also, get_nr_inodes() is also called by get_nr_dirty_inodes(), which is > called by the high level inode writeback code, so will typically be > called in the order of tens of times per second, and the number of > calls increased depending on the number of filesystems that are > active. It's still much higher frequency than your "cat > /proc/sys/fs/inode-nr" example indicates it might be called. > > So I'd say that by your reasoning, the choice of using the generic > percpu counters is the right one to make. You missed one thing : In cases you mention, you want a precise count (aka percpu_counter_sum_positive()), not the approximate one (aka percpu_counter_read_positive()). The only difference is then the possible/online cpu loop difference. I am saying : No need to maintain an approximate counter if we dont _read_ it, ever. Andrew answer : Eric, cant you implement this generically ? -- 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
