On Fri, Jan 20, 2023 at 11:27:12AM -0500, Johannes Weiner wrote: > On Fri, Jan 20, 2023 at 09:34:18AM -0500, Brian Foster wrote: > > On Tue, Jan 17, 2023 at 11:59:57AM -0800, Nhat Pham wrote: > > > + int memcgid; > > > + struct pglist_data *pgdat; > > > + unsigned long token; > > > + > > > + unpack_shadow(shadow, &memcgid, &pgdat, &token, workingset); > > > + eviction_memcg = mem_cgroup_from_id(memcgid); > > > + > > > + lruvec = mem_cgroup_lruvec(eviction_memcg, pgdat); > > > + lrugen = &lruvec->lrugen; > > > + > > > + min_seq = READ_ONCE(lrugen->min_seq[file]); > > > + return !((token >> LRU_REFS_WIDTH) != (min_seq & (EVICTION_MASK >> LRU_REFS_WIDTH))); > > > > I think this might be more readable without the double negative. > > > > Also it looks like this logic is pulled from lru_gen_refault(). Any > > reason the caller isn't refactored to use this helper, similar to how > > workingset_refault() is modified? It seems like a potential landmine to > > duplicate the logic here for cachestat purposes and somewhere else for > > actual workingset management. > > The initial version was refactored. Yu explicitly requested it be > duplicated [1] to cut down on some boiler plate. > Ah, sorry for missing the previous discussion. TBH I wasn't terribly comfortable reviewing this one until I had made enough passes at the second patch.. > I have to agree with Brian on this one, though. The factored version > is better for maintenance than duplicating the core logic here. Even > if it ends up a bit more boiler plate - it's harder to screw that up, > and easier to catch at compile time, than the duplicates diverging. > It seems more elegant to me, FWIW. Glad I'm not totally off the rails at least. ;) But I'll defer to those who know the code better and the author, so that's just my .02. I don't want to cause this to go around in circles.. Brian > [1] https://lore.kernel.org/lkml/CAOUHufZKTqoD2rFwrX9-eCknBmeWqP88rZ7X7A_5KHHbGBUP=A@xxxxxxxxxxxxxx/ >
