On Tue, Jul 23, 2024 at 8:35 AM Takero Funaki <flintglass@xxxxxxxxx> wrote: > > 2024年7月23日(火) 6:39 Nhat Pham <nphamcs@xxxxxxxxx>: > > > > On Fri, Jul 19, 2024 at 9:41 PM Takero Funaki <flintglass@xxxxxxxxx> wrote: > > > > > > This patch fixes an issue where the zswap global shrinker stopped > > > iterating through the memcg tree. > > > > > > The problem was that shrink_worker() would stop iterating when a memcg > > > was being offlined and restart from the tree root. Now, it properly > > > handles the offline memcg and continues shrinking with the next memcg. > > > > > > To avoid holding refcount of offline memcg encountered during the memcg > > > tree walking, shrink_worker() must continue iterating to release the > > > offline memcg to ensure the next memcg stored in the cursor is online. > > > > > > The offline memcg cleaner has also been changed to avoid the same issue. > > > When the next memcg of the offlined memcg is also offline, the refcount > > > stored in the iteration cursor was held until the next shrink_worker() > > > run. The cleaner must release the offline memcg recursively. > > > > > > Fixes: a65b0e7607cc ("zswap: make shrinking memcg-aware") > > > Signed-off-by: Takero Funaki <flintglass@xxxxxxxxx> > > Hmm LGTM for the most part - a couple nits > > [...] > > > + zswap_next_shrink = mem_cgroup_iter(NULL, > > > + zswap_next_shrink, NULL); > > nit: this can fit in a single line right? Looks like it's exactly 80 characters. > > Isn't that over 90 chars? But yes, we can reduce line breaks using > memcg as temporary, like: Huh. Weird. I applied the patch locally, and it looked 80 chars to me ha. Anyway - just some nits. If checkpatch complains then yeah no need to fix this.