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AJvYcCVXWegLsKldfxlc4CDIba+kvrT8qd/ej3TASe26TigHEmPpkD5uZMQrmyljJtWNCQzVXW0yRe7p+w==@kvack.org X-Gm-Message-State: AOJu0YxuL8WeVaPcglA7glxLbtS6iR75FbEtH3W7gLnorWDP6oUJNaEY t8gVof+1W9H4mkfWbv3elKCIloCcx22cMb0qGmUKH8ZLBLGVJxCG/27RW8gT5L48krFJJlLx0eP u3hxrA7hBsPYVFvTGp95LXknkzZuY2vTkijLj X-Google-Smtp-Source: AGHT+IHz1mc7wzRpBmD+b6Xl5CBMCT4PuOVm744FyVXy2jW4DjjiSTdUedMAyy3WPUqWtFYCtXSK9uKEhnOaTqbMvbs= X-Received: by 2002:a17:907:a01:b0:a8d:e49:c530 with SMTP id a640c23a62f3a-a93c4a671bbmr565728466b.42.1727492306965; Fri, 27 Sep 2024 19:58:26 -0700 (PDT) MIME-Version: 1.0 References: <20240928021620.8369-1-kanchana.p.sridhar@intel.com> <20240928021620.8369-6-kanchana.p.sridhar@intel.com> In-Reply-To: <20240928021620.8369-6-kanchana.p.sridhar@intel.com> From: Yosry Ahmed Date: Fri, 27 Sep 2024 19:57:49 -0700 Message-ID: Subject: Re: [PATCH v8 5/8] mm: zswap: Modify zswap_stored_pages to be atomic_long_t. To: Kanchana P Sridhar Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, hannes@cmpxchg.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-Rspam-User: X-Rspamd-Queue-Id: C834D40002 X-Rspamd-Server: rspam01 X-Stat-Signature: goo99odpc5a8ix1ufq8depu4gb1x51bp X-HE-Tag: 1727492308-458226 X-HE-Meta: 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 mX7SjSEd rfmenMg3n3uKQjCQfm7kz/9Y5zYS7/hYyH/DFiNNgDskdR6qACclrEC9DjqFesT+hez/Q9vMM2rfcTGX9LIQjjUNMEgmdJInal4nf8f2lsG/XqPUzwqkaypMaoMOdx+zSfM3wY/oeVGUdhB1+QvJstd1F7NcVthry3mHU9QCeOk+ApI8Ti3od/oMR/EtYeTIQTiVr4jBwV5sZk2ILgAX4TfFK04AkB8LdleFGB9vQBGQGmjbFWojTDyHI00f6EOxWBMycc+pulh+IbQE= 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 Fri, Sep 27, 2024 at 7:16=E2=80=AFPM Kanchana P Sridhar wrote: > > For zswap_store() to support large folios, we need to be able to do > a batch update of zswap_stored_pages upon successful store of all pages > in the folio. For this, we need to add folio_nr_pages(), which returns > a long, to zswap_stored_pages. Do we really need this? A lot of places in the kernel assign the result of folio_nr_pages() to an int (thp_nr_pages(), split_huge_pages_all(), etc). I don't think we need to worry about folio_nr_pages() exceeding INT_MAX for a while. > > Signed-off-by: Kanchana P Sridhar > --- > fs/proc/meminfo.c | 2 +- > include/linux/zswap.h | 2 +- > mm/zswap.c | 19 +++++++++++++------ > 3 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c > index 245171d9164b..8ba9b1472390 100644 > --- a/fs/proc/meminfo.c > +++ b/fs/proc/meminfo.c > @@ -91,7 +91,7 @@ static int meminfo_proc_show(struct seq_file *m, void *= v) > #ifdef CONFIG_ZSWAP > show_val_kb(m, "Zswap: ", zswap_total_pages()); > seq_printf(m, "Zswapped: %8lu kB\n", > - (unsigned long)atomic_read(&zswap_stored_pages) << > + (unsigned long)atomic_long_read(&zswap_stored_pages) <= < > (PAGE_SHIFT - 10)); > #endif > show_val_kb(m, "Dirty: ", > diff --git a/include/linux/zswap.h b/include/linux/zswap.h > index 9cd1beef0654..d961ead91bf1 100644 > --- a/include/linux/zswap.h > +++ b/include/linux/zswap.h > @@ -7,7 +7,7 @@ > > struct lruvec; > > -extern atomic_t zswap_stored_pages; > +extern atomic_long_t zswap_stored_pages; > > #ifdef CONFIG_ZSWAP > > diff --git a/mm/zswap.c b/mm/zswap.c > index 0f281e50a034..43e4e216db41 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -43,7 +43,7 @@ > * statistics > **********************************/ > /* The number of compressed pages currently stored in zswap */ > -atomic_t zswap_stored_pages =3D ATOMIC_INIT(0); > +atomic_long_t zswap_stored_pages =3D ATOMIC_INIT(0); > > /* > * The statistics below are not protected from concurrent access for > @@ -802,7 +802,7 @@ static void zswap_entry_free(struct zswap_entry *entr= y) > obj_cgroup_put(entry->objcg); > } > zswap_entry_cache_free(entry); > - atomic_dec(&zswap_stored_pages); > + atomic_long_dec(&zswap_stored_pages); > } > > /********************************* > @@ -1232,7 +1232,7 @@ static unsigned long zswap_shrinker_count(struct sh= rinker *shrinker, > nr_stored =3D memcg_page_state(memcg, MEMCG_ZSWAPPED); > } else { > nr_backing =3D zswap_total_pages(); > - nr_stored =3D atomic_read(&zswap_stored_pages); > + nr_stored =3D atomic_long_read(&zswap_stored_pages); > } > > if (!nr_stored) > @@ -1501,7 +1501,7 @@ bool zswap_store(struct folio *folio) > } > > /* update stats */ > - atomic_inc(&zswap_stored_pages); > + atomic_long_inc(&zswap_stored_pages); > count_vm_event(ZSWPOUT); > > return true; > @@ -1650,6 +1650,13 @@ static int debugfs_get_total_size(void *data, u64 = *val) > } > DEFINE_DEBUGFS_ATTRIBUTE(total_size_fops, debugfs_get_total_size, NULL, = "%llu\n"); > > +static int debugfs_get_stored_pages(void *data, u64 *val) > +{ > + *val =3D atomic_long_read(&zswap_stored_pages); > + return 0; > +} > +DEFINE_DEBUGFS_ATTRIBUTE(stored_pages_fops, debugfs_get_stored_pages, NU= LL, "%llu\n"); > + > static int zswap_debugfs_init(void) > { > if (!debugfs_initialized()) > @@ -1673,8 +1680,8 @@ static int zswap_debugfs_init(void) > zswap_debugfs_root, &zswap_written_back_pages)= ; > debugfs_create_file("pool_total_size", 0444, > zswap_debugfs_root, NULL, &total_size_fops); > - debugfs_create_atomic_t("stored_pages", 0444, > - zswap_debugfs_root, &zswap_stored_pages); > + debugfs_create_file("stored_pages", 0444, > + zswap_debugfs_root, NULL, &stored_pages_fops)= ; > > return 0; > } > -- > 2.27.0 >