On Mon 30-06-25 18:02:49, Baokun Li wrote: > On 2025/6/30 16:38, Jan Kara wrote: > > We could make streaming goal to be ext4_fsblk_t so that also offset of the > > last big allocation in the group is recorded as I wrote above. That would > > tend to pack big allocations in each group together which is benefitial to > > combat fragmentation even with higher proportion of groups that are streaming > > goals (and likely becomes more important as the blocksize and thus group > > size grow). We can discuss proper number of slots for streaming allocation > > (I'm not hung up on it being quarter of the group count) but I'm convinced > > sb->s_groups_count is too much :) > > > > Honza > > I think sbi->s_groups_count / 4 is indeed acceptable. However, I don't > believe recording offsets is necessary. As groups become larger, > contention for groups will intensify, and adding offsets would only > make this contention worse. I agree the contention for groups will increase when the group count goes down. I just thought offsets may help to find free space faster in large groups (and thus reduce contention) and also reduce free space fragmentation within a group (by having higher chances of placing large allocations close together within a group) but maybe that's not the case. Offsets are definitely not requirement at this point. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
