On Thu, Mar 15, 2012 at 10:49 AM, Yongqiang Yang <xiaoqiangnk@xxxxxxxxx> wrote: > On Thu, Mar 15, 2012 at 10:34 AM, Andreas Dilger <adilger@xxxxxxxxx> wrote: >> On 2012-03-14, at 6:52 PM, Yongqiang Yang wrote: >>> Here is a proposal to enable ext4 allocate blocks across group boundary. >>> >>> Now ext4 allocates blocks within a single block group by locking a >>> group. Flex_bg puts metadata blocks together, as a result,it >>> enlarges contiguous blocks. So we can enable ext4 allocate blocks >>> within a flex block group. Inode allocation takes group lock as block >>> allocation, I am not sure if we should allocate inode within single >>> group as before. >>> >>> If we do this, then the new group boundary will be flex block group >>> boundary. I am not sure if it is worth doing. >> >> The maximum extent size is the same as a single block group, so there >> is relatively little value in doing this, IMHO. > nope. The value comes from 2 aspects: 1. the preallocation can > preallocate much more space , 2. if tail blocks of a group and head > blocks of the next group is free, then they can be treated as > contiguous blocks. Here I meant they can be seen in buddy allocator. Yongqiang. > > I had a rough look at the code, current code does not handle the situation. > > Yongqiang. >> >> Cheers, Andreas >> >> >> >> >> > > > > -- > Best Wishes > Yongqiang Yang -- Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
