On Wed, Nov 29, 2023 at 7:25 AM Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
>
> On Mon, Nov 27, 2023 at 03:45:58PM -0800, Nhat Pham wrote:
> > From: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
> >
> > Since zswap now writes back pages from memcg-specific LRUs, we now need a
> > new stat to show writebacks count for each memcg.
> >
> > Suggested-by: Nhat Pham <nphamcs@xxxxxxxxx>
> > Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx>
> > Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx>
> > ---
> > include/linux/vm_event_item.h | 1 +
> > mm/memcontrol.c | 1 +
> > mm/vmstat.c | 1 +
> > mm/zswap.c | 3 +++
> > 4 files changed, 6 insertions(+)
> >
> > diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
> > index d1b847502f09..f4569ad98edf 100644
> > --- a/include/linux/vm_event_item.h
> > +++ b/include/linux/vm_event_item.h
> > @@ -142,6 +142,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
> > #ifdef CONFIG_ZSWAP
> > ZSWPIN,
> > ZSWPOUT,
> > + ZSWP_WB,
> > #endif
> > #ifdef CONFIG_X86
> > DIRECT_MAP_LEVEL2_SPLIT,
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 8c0f3f971179..f88c8fd03689 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -703,6 +703,7 @@ static const unsigned int memcg_vm_event_stat[] = {
> > #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
> > ZSWPIN,
> > ZSWPOUT,
> > + ZSWP_WB,
> > #endif
> > #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> > THP_FAULT_ALLOC,
> > diff --git a/mm/vmstat.c b/mm/vmstat.c
> > index afa5a38fcc9c..2249f85e4a87 100644
> > --- a/mm/vmstat.c
> > +++ b/mm/vmstat.c
> > @@ -1401,6 +1401,7 @@ const char * const vmstat_text[] = {
> > #ifdef CONFIG_ZSWAP
> > "zswpin",
> > "zswpout",
> > + "zswp_wb",
>
> ZSWPWB and "zswpwb" would match the existing naming scheme a bit
> better.
>
> > #endif
> > #ifdef CONFIG_X86
> > "direct_map_level2_splits",
> > diff --git a/mm/zswap.c b/mm/zswap.c
> > index 5e397fc1f375..6a761753f979 100644
> > --- a/mm/zswap.c
> > +++ b/mm/zswap.c
> > @@ -754,6 +754,9 @@ static enum lru_status shrink_memcg_cb(struct list_head *item, struct list_lru_o
> > }
> > zswap_written_back_pages++;
> >
> > + if (entry->objcg)
> > + count_objcg_event(entry->objcg, ZSWP_WB);
> > +
>
> You need to call count_vm_event() as well, otherwise the /proc/vmstat
> counter will stay zero.
Ahh I didn't check that. I only looked at the cgroup's memory.stat
counter. I'll fix this for v8!
