> -----Original Message-----
> From: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
> Sent: Saturday, September 28, 2024 1:13 AM
> To: Sridhar, Kanchana P <kanchana.p.sridhar@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx;
> hannes@xxxxxxxxxxx; nphamcs@xxxxxxxxx; chengming.zhou@xxxxxxxxx;
> usamaarif642@xxxxxxxxx; shakeel.butt@xxxxxxxxx; ryan.roberts@xxxxxxx;
> Huang, Ying <ying.huang@xxxxxxxxx>; 21cnbao@xxxxxxxxx; akpm@linux-
> foundation.org; Zou, Nanhai <nanhai.zou@xxxxxxxxx>; Feghali, Wajdi K
> <wajdi.k.feghali@xxxxxxxxx>; Gopal, Vinodh <vinodh.gopal@xxxxxxxxx>
> Subject: Re: [PATCH v8 5/8] mm: zswap: Modify zswap_stored_pages to be
> atomic_long_t.
>
> On Fri, Sep 27, 2024 at 7:16 PM Kanchana P Sridhar
> <kanchana.p.sridhar@xxxxxxxxx> 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.
> >
> > Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@xxxxxxxxx>
> > ---
> > 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) <<
>
> Do we still need this cast? "HardwareCorrupted" seems to be using
> atomic_long_read() without a cast.
>
> Otherwise this LGTM:
> Acked-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Thanks Yosry for the Acked-by's!
Thanks,
Kanchana
>
> > (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 = ATOMIC_INIT(0);
> > +atomic_long_t zswap_stored_pages = 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
> *entry)
> > 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
> shrinker *shrinker,
> > nr_stored = memcg_page_state(memcg, MEMCG_ZSWAPPED);
> > } else {
> > nr_backing = zswap_total_pages();
> > - nr_stored = atomic_read(&zswap_stored_pages);
> > + nr_stored = 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 = atomic_long_read(&zswap_stored_pages);
> > + return 0;
> > +}
> > +DEFINE_DEBUGFS_ATTRIBUTE(stored_pages_fops,
> debugfs_get_stored_pages, NULL, "%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
> >
