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To: Johannes Weiner Cc: Kanchana P Sridhar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, nphamcs@gmail.com, chengming.zhou@linux.dev, usamaarif642@gmail.com, shakeel.butt@linux.dev, ryan.roberts@arm.com, ying.huang@intel.com, 21cnbao@gmail.com, akpm@linux-foundation.org, nanhai.zou@intel.com, wajdi.k.feghali@intel.com, vinodh.gopal@intel.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 6557EA0006 X-Stat-Signature: baou8i11mw1af16pgwtcek6opkksxw4j X-Rspam-User: X-HE-Tag: 1727547127-259210 X-HE-Meta: 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 OfMbg/Cz TD3fq81cJnaRoUtdIMrRjd+Q7u7dvjkVmDd6bX5HeKW1Nou072kHutSOpa7aZgn/AbpHPEC/aGq5b3ZGAKKDnn7jtFTwLqOO4inIHwJgPnYIDJhl4mSHj+yOrW5hAMSFVSAlt47jq2hbiQwBzXmJryT/TP1J33BQkd013GwuVhpuiEtb91s1nmus/1os2/3D/qV/hpxPOdpV2HjBjC0ZY+tVVPSxCgYCpAO+lDAPWrEXShNhj6RbzPInvnzq9RyY+bTvhUJdWfdDP/3SsQf4JKI9uZFAT+pb/sMvwYCtyf/crEzY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Sep 28, 2024 at 7:15=E2=80=AFAM Johannes Weiner wrote: > > On Fri, Sep 27, 2024 at 08:42:16PM -0700, Yosry Ahmed wrote: > > On Fri, Sep 27, 2024 at 7:16=E2=80=AFPM Kanchana P Sridhar > > > { > > > + struct page *page =3D folio_page(folio, index); > > > swp_entry_t swp =3D folio->swap; > > > - pgoff_t offset =3D swp_offset(swp); > > > struct xarray *tree =3D swap_zswap_tree(swp); > > > + pgoff_t offset =3D swp_offset(swp) + index; > > > struct zswap_entry *entry, *old; > > > - struct obj_cgroup *objcg =3D NULL; > > > - struct mem_cgroup *memcg =3D NULL; > > > - > > > - VM_WARN_ON_ONCE(!folio_test_locked(folio)); > > > - VM_WARN_ON_ONCE(!folio_test_swapcache(folio)); > > > + int type =3D swp_type(swp); > > > > Why do we need type? We use it when initializing entry->swpentry to > > reconstruct the swp_entry_t we already have. > > It's not the same entry. folio->swap points to the head entry, this > function has to store swap entries with the offsets of each subpage. Duh, yeah, thanks. > > Given the name of this function, it might be better to actually pass a > page pointer to it; do the folio_page() inside zswap_store(). > > Then do > > entry->swpentry =3D page_swap_entry(page); > > below. That is indeed clearer. Although this will be adding yet another caller of page_swap_entry() that already has the folio, yet it calls page_swap_entry() for each page in the folio, which calls page_folio() inside. I wonder if we should add (or replace page_swap_entry()) with a folio_swap_entry(folio, index) helper. This can also be done as a follow up. > > > > obj_cgroup_put(objcg); > > > - if (zswap_pool_reached_full) > > > - queue_work(shrink_wq, &zswap_shrink_work); > > > -check_old: > > > + return false; > > > +} > > > + > > > +bool zswap_store(struct folio *folio) > > > +{ > > > + long nr_pages =3D folio_nr_pages(folio); > > > + swp_entry_t swp =3D folio->swap; > > > + struct xarray *tree =3D swap_zswap_tree(swp); > > > + pgoff_t offset =3D swp_offset(swp); > > > + struct obj_cgroup *objcg =3D NULL; > > > + struct mem_cgroup *memcg =3D NULL; > > > + struct zswap_pool *pool; > > > + size_t compressed_bytes =3D 0; > > > > Why size_t? entry->length is int. > > In light of Willy's comment, I think size_t is a good idea. Agreed.