| Message ID | 20191022144803.302233-5-hannes@cmpxchg.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | : mm: vmscan: cgroup-related cleanups | expand |
On Tue, Oct 22, 2019 at 10:47:59AM -0400, Johannes Weiner wrote: > Seven years after introducing the global_reclaim() function, I still > have to double take when reading a callsite. I don't know how others > do it, this is a terrible name. > > Invert the meaning and rename it to cgroup_reclaim(). > > [ After all, "global reclaim" is just regular reclaim invoked from the > page allocator. It's reclaim on behalf of a cgroup limit that is a > special case of reclaim, and should be explicit - not the reverse. ] > > sane_reclaim() isn't very descriptive either: it tests whether we can > use the regular writeback throttling - available during regular page > reclaim or cgroup2 limit reclaim - or need to use the broken > wait_on_page_writeback() method. Use "writeback_throttling_sane()". > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> > --- > mm/vmscan.c | 38 ++++++++++++++++++-------------------- > 1 file changed, 18 insertions(+), 20 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 622b77488144..302dad112f75 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -239,13 +239,13 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > up_write(&shrinker_rwsem); > } > > -static bool global_reclaim(struct scan_control *sc) > +static bool cgroup_reclaim(struct scan_control *sc) > { > - return !sc->target_mem_cgroup; > + return sc->target_mem_cgroup; > } Isn't targeted_reclaim() better? cgroup_reclaim() is also ok to me, but it sounds a bit like we reclaim from this specific cgroup. Also targeted/global is IMO a better opposition than cgroup/global (the latter reminds me days when there were global and cgroup LRUs). The rest of the patch looks good! Reviewed-by: Roman Gushchin <guro@fb.com> > > /** > - * sane_reclaim - is the usual dirty throttling mechanism operational? > + * writeback_throttling_sane - is the usual dirty throttling mechanism available? > * @sc: scan_control in question > * > * The normal page dirty throttling mechanism in balance_dirty_pages() is > @@ -257,11 +257,9 @@ static bool global_reclaim(struct scan_control *sc) > * This function tests whether the vmscan currently in progress can assume > * that the normal dirty throttling mechanism is operational. > */ > -static bool sane_reclaim(struct scan_control *sc) > +static bool writeback_throttling_sane(struct scan_control *sc) > { > - struct mem_cgroup *memcg = sc->target_mem_cgroup; > - > - if (!memcg) > + if (!cgroup_reclaim(sc)) > return true; > #ifdef CONFIG_CGROUP_WRITEBACK > if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > @@ -302,12 +300,12 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > { > } > > -static bool global_reclaim(struct scan_control *sc) > +static bool cgroup_reclaim(struct scan_control *sc) > { > - return true; > + return false; > } > > -static bool sane_reclaim(struct scan_control *sc) > +static bool writeback_throttling_sane(struct scan_control *sc) > { > return true; > } > @@ -1227,7 +1225,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, > goto activate_locked; > > /* Case 2 above */ > - } else if (sane_reclaim(sc) || > + } else if (writeback_throttling_sane(sc) || > !PageReclaim(page) || !may_enter_fs) { > /* > * This is slightly racy - end_page_writeback() > @@ -1821,7 +1819,7 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > if (current_is_kswapd()) > return 0; > > - if (!sane_reclaim(sc)) > + if (!writeback_throttling_sane(sc)) > return 0; > > if (file) { > @@ -1971,7 +1969,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > reclaim_stat->recent_scanned[file] += nr_taken; > > item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT; > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_scanned); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); > spin_unlock_irq(&pgdat->lru_lock); > @@ -1985,7 +1983,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > spin_lock_irq(&pgdat->lru_lock); > > item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_reclaimed); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); > reclaim_stat->recent_rotated[0] += stat.nr_activate[0]; > @@ -2309,7 +2307,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, > * using the memory controller's swap limit feature would be > * too expensive. > */ > - if (!global_reclaim(sc) && !swappiness) { > + if (cgroup_reclaim(sc) && !swappiness) { > scan_balance = SCAN_FILE; > goto out; > } > @@ -2333,7 +2331,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, > * thrashing file LRU becomes infinitely more attractive than > * anon pages. Try to detect this based on file LRU size. > */ > - if (global_reclaim(sc)) { > + if (!cgroup_reclaim(sc)) { > unsigned long pgdatfile; > unsigned long pgdatfree; > int z; > @@ -2564,7 +2562,7 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc > * abort proportional reclaim if either the file or anon lru has already > * dropped to zero at the first pass. > */ > - scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() && > + scan_adjusted = (!cgroup_reclaim(sc) && !current_is_kswapd() && > sc->priority == DEF_PRIORITY); > > blk_start_plug(&plug); > @@ -2853,7 +2851,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) > * Legacy memcg will stall in page writeback so avoid forcibly > * stalling in wait_iff_congested(). > */ > - if (!global_reclaim(sc) && sane_reclaim(sc) && > + if (cgroup_reclaim(sc) && writeback_throttling_sane(sc) && > sc->nr.dirty && sc->nr.dirty == sc->nr.congested) > set_memcg_congestion(pgdat, root, true); > > @@ -2948,7 +2946,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) > * Take care memory controller reclaiming has small influence > * to global LRU. > */ > - if (global_reclaim(sc)) { > + if (!cgroup_reclaim(sc)) { > if (!cpuset_zone_allowed(zone, > GFP_KERNEL | __GFP_HARDWALL)) > continue; > @@ -3048,7 +3046,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > retry: > delayacct_freepages_start(); > > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_zid_vm_events(ALLOCSTALL, sc->reclaim_idx, 1); > > do { > -- > 2.23.0 >
On Tue 22-10-19 10:47:59, Johannes Weiner wrote: > Seven years after introducing the global_reclaim() function, I still > have to double take when reading a callsite. I don't know how others > do it, this is a terrible name. I somehow never had problem with that but ... > > Invert the meaning and rename it to cgroup_reclaim(). > > [ After all, "global reclaim" is just regular reclaim invoked from the > page allocator. It's reclaim on behalf of a cgroup limit that is a > special case of reclaim, and should be explicit - not the reverse. ] ... this is a valid point. > sane_reclaim() isn't very descriptive either: it tests whether we can > use the regular writeback throttling - available during regular page > reclaim or cgroup2 limit reclaim - or need to use the broken > wait_on_page_writeback() method. Use "writeback_throttling_sane()". I do have a stronger opinion on this one. sane_reclaim is really a terrible name. As you say the only thing this should really tell is whether writeback throttling is available so I would rather go with has_writeback_throttling() or writeba_throttling_{eabled,available} If you insist on having sane in the name then I won't object but it just raises a question whether we have some levels of throttling with a different level of sanity. > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> > --- > mm/vmscan.c | 38 ++++++++++++++++++-------------------- > 1 file changed, 18 insertions(+), 20 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 622b77488144..302dad112f75 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -239,13 +239,13 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > up_write(&shrinker_rwsem); > } > > -static bool global_reclaim(struct scan_control *sc) > +static bool cgroup_reclaim(struct scan_control *sc) > { > - return !sc->target_mem_cgroup; > + return sc->target_mem_cgroup; > } > > /** > - * sane_reclaim - is the usual dirty throttling mechanism operational? > + * writeback_throttling_sane - is the usual dirty throttling mechanism available? > * @sc: scan_control in question > * > * The normal page dirty throttling mechanism in balance_dirty_pages() is > @@ -257,11 +257,9 @@ static bool global_reclaim(struct scan_control *sc) > * This function tests whether the vmscan currently in progress can assume > * that the normal dirty throttling mechanism is operational. > */ > -static bool sane_reclaim(struct scan_control *sc) > +static bool writeback_throttling_sane(struct scan_control *sc) > { > - struct mem_cgroup *memcg = sc->target_mem_cgroup; > - > - if (!memcg) > + if (!cgroup_reclaim(sc)) > return true; > #ifdef CONFIG_CGROUP_WRITEBACK > if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > @@ -302,12 +300,12 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > { > } > > -static bool global_reclaim(struct scan_control *sc) > +static bool cgroup_reclaim(struct scan_control *sc) > { > - return true; > + return false; > } > > -static bool sane_reclaim(struct scan_control *sc) > +static bool writeback_throttling_sane(struct scan_control *sc) > { > return true; > } > @@ -1227,7 +1225,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, > goto activate_locked; > > /* Case 2 above */ > - } else if (sane_reclaim(sc) || > + } else if (writeback_throttling_sane(sc) || > !PageReclaim(page) || !may_enter_fs) { > /* > * This is slightly racy - end_page_writeback() > @@ -1821,7 +1819,7 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > if (current_is_kswapd()) > return 0; > > - if (!sane_reclaim(sc)) > + if (!writeback_throttling_sane(sc)) > return 0; > > if (file) { > @@ -1971,7 +1969,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > reclaim_stat->recent_scanned[file] += nr_taken; > > item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT; > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_scanned); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); > spin_unlock_irq(&pgdat->lru_lock); > @@ -1985,7 +1983,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > spin_lock_irq(&pgdat->lru_lock); > > item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_reclaimed); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); > reclaim_stat->recent_rotated[0] += stat.nr_activate[0]; > @@ -2309,7 +2307,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, > * using the memory controller's swap limit feature would be > * too expensive. > */ > - if (!global_reclaim(sc) && !swappiness) { > + if (cgroup_reclaim(sc) && !swappiness) { > scan_balance = SCAN_FILE; > goto out; > } > @@ -2333,7 +2331,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, > * thrashing file LRU becomes infinitely more attractive than > * anon pages. Try to detect this based on file LRU size. > */ > - if (global_reclaim(sc)) { > + if (!cgroup_reclaim(sc)) { > unsigned long pgdatfile; > unsigned long pgdatfree; > int z; > @@ -2564,7 +2562,7 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc > * abort proportional reclaim if either the file or anon lru has already > * dropped to zero at the first pass. > */ > - scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() && > + scan_adjusted = (!cgroup_reclaim(sc) && !current_is_kswapd() && > sc->priority == DEF_PRIORITY); > > blk_start_plug(&plug); > @@ -2853,7 +2851,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) > * Legacy memcg will stall in page writeback so avoid forcibly > * stalling in wait_iff_congested(). > */ > - if (!global_reclaim(sc) && sane_reclaim(sc) && > + if (cgroup_reclaim(sc) && writeback_throttling_sane(sc) && > sc->nr.dirty && sc->nr.dirty == sc->nr.congested) > set_memcg_congestion(pgdat, root, true); > > @@ -2948,7 +2946,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) > * Take care memory controller reclaiming has small influence > * to global LRU. > */ > - if (global_reclaim(sc)) { > + if (!cgroup_reclaim(sc)) { > if (!cpuset_zone_allowed(zone, > GFP_KERNEL | __GFP_HARDWALL)) > continue; > @@ -3048,7 +3046,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > retry: > delayacct_freepages_start(); > > - if (global_reclaim(sc)) > + if (!cgroup_reclaim(sc)) > __count_zid_vm_events(ALLOCSTALL, sc->reclaim_idx, 1); > > do { > -- > 2.23.0
On Wed, Oct 23, 2019 at 04:14:36PM +0200, Michal Hocko wrote: > On Tue 22-10-19 10:47:59, Johannes Weiner wrote: > > Seven years after introducing the global_reclaim() function, I still > > have to double take when reading a callsite. I don't know how others > > do it, this is a terrible name. > > I somehow never had problem with that but ... > > > > Invert the meaning and rename it to cgroup_reclaim(). > > > > [ After all, "global reclaim" is just regular reclaim invoked from the > > page allocator. It's reclaim on behalf of a cgroup limit that is a > > special case of reclaim, and should be explicit - not the reverse. ] > > ... this is a valid point. > > > sane_reclaim() isn't very descriptive either: it tests whether we can > > use the regular writeback throttling - available during regular page > > reclaim or cgroup2 limit reclaim - or need to use the broken > > wait_on_page_writeback() method. Use "writeback_throttling_sane()". > > I do have a stronger opinion on this one. sane_reclaim is really a > terrible name. As you say the only thing this should really tell is > whether writeback throttling is available so I would rather go with > has_writeback_throttling() or writeba_throttling_{eabled,available} > If you insist on having sane in the name then I won't object but it just > raises a question whether we have some levels of throttling with a > different level of sanity. I mean, cgroup1 *does* have a method to not OOM due to pages under writeback: wait_on_page_writeback() on each wb page on the LRU. It's terrible, but it's a form of writeback throttling. That's what the sane vs insane distinction is about, I guess: we do in fact have throttling implementations with different levels of sanity. > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> > > Acked-by: Michal Hocko <mhocko@suse.com> Thanks!
On Tue, Oct 22, 2019 at 07:40:52PM +0000, Roman Gushchin wrote: > On Tue, Oct 22, 2019 at 10:47:59AM -0400, Johannes Weiner wrote: > > Seven years after introducing the global_reclaim() function, I still > > have to double take when reading a callsite. I don't know how others > > do it, this is a terrible name. > > > > Invert the meaning and rename it to cgroup_reclaim(). > > > > [ After all, "global reclaim" is just regular reclaim invoked from the > > page allocator. It's reclaim on behalf of a cgroup limit that is a > > special case of reclaim, and should be explicit - not the reverse. ] > > > > sane_reclaim() isn't very descriptive either: it tests whether we can > > use the regular writeback throttling - available during regular page > > reclaim or cgroup2 limit reclaim - or need to use the broken > > wait_on_page_writeback() method. Use "writeback_throttling_sane()". > > > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> > > --- > > mm/vmscan.c | 38 ++++++++++++++++++-------------------- > > 1 file changed, 18 insertions(+), 20 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 622b77488144..302dad112f75 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -239,13 +239,13 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > > up_write(&shrinker_rwsem); > > } > > > > -static bool global_reclaim(struct scan_control *sc) > > +static bool cgroup_reclaim(struct scan_control *sc) > > { > > - return !sc->target_mem_cgroup; > > + return sc->target_mem_cgroup; > > } > > Isn't targeted_reclaim() better? > > cgroup_reclaim() is also ok to me, but it sounds a bit like we reclaim > from this specific cgroup. Also targeted/global is IMO a better opposition > than cgroup/global (the latter reminds me days when there were global > and cgroup LRUs). I think "targeted" is quite a bit less descriptive when you come at the page replacement algorithm without cgroups in mind. > The rest of the patch looks good! > > Reviewed-by: Roman Gushchin <guro@fb.com> Thanks!
diff --git a/mm/vmscan.c b/mm/vmscan.c index 622b77488144..302dad112f75 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -239,13 +239,13 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) up_write(&shrinker_rwsem); } -static bool global_reclaim(struct scan_control *sc) +static bool cgroup_reclaim(struct scan_control *sc) { - return !sc->target_mem_cgroup; + return sc->target_mem_cgroup; } /** - * sane_reclaim - is the usual dirty throttling mechanism operational? + * writeback_throttling_sane - is the usual dirty throttling mechanism available? * @sc: scan_control in question * * The normal page dirty throttling mechanism in balance_dirty_pages() is @@ -257,11 +257,9 @@ static bool global_reclaim(struct scan_control *sc) * This function tests whether the vmscan currently in progress can assume * that the normal dirty throttling mechanism is operational. */ -static bool sane_reclaim(struct scan_control *sc) +static bool writeback_throttling_sane(struct scan_control *sc) { - struct mem_cgroup *memcg = sc->target_mem_cgroup; - - if (!memcg) + if (!cgroup_reclaim(sc)) return true; #ifdef CONFIG_CGROUP_WRITEBACK if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) @@ -302,12 +300,12 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) { } -static bool global_reclaim(struct scan_control *sc) +static bool cgroup_reclaim(struct scan_control *sc) { - return true; + return false; } -static bool sane_reclaim(struct scan_control *sc) +static bool writeback_throttling_sane(struct scan_control *sc) { return true; } @@ -1227,7 +1225,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, goto activate_locked; /* Case 2 above */ - } else if (sane_reclaim(sc) || + } else if (writeback_throttling_sane(sc) || !PageReclaim(page) || !may_enter_fs) { /* * This is slightly racy - end_page_writeback() @@ -1821,7 +1819,7 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, if (current_is_kswapd()) return 0; - if (!sane_reclaim(sc)) + if (!writeback_throttling_sane(sc)) return 0; if (file) { @@ -1971,7 +1969,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, reclaim_stat->recent_scanned[file] += nr_taken; item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT; - if (global_reclaim(sc)) + if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_scanned); __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); spin_unlock_irq(&pgdat->lru_lock); @@ -1985,7 +1983,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, spin_lock_irq(&pgdat->lru_lock); item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; - if (global_reclaim(sc)) + if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_reclaimed); __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); reclaim_stat->recent_rotated[0] += stat.nr_activate[0]; @@ -2309,7 +2307,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, * using the memory controller's swap limit feature would be * too expensive. */ - if (!global_reclaim(sc) && !swappiness) { + if (cgroup_reclaim(sc) && !swappiness) { scan_balance = SCAN_FILE; goto out; } @@ -2333,7 +2331,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, * thrashing file LRU becomes infinitely more attractive than * anon pages. Try to detect this based on file LRU size. */ - if (global_reclaim(sc)) { + if (!cgroup_reclaim(sc)) { unsigned long pgdatfile; unsigned long pgdatfree; int z; @@ -2564,7 +2562,7 @@ static void shrink_node_memcg(struct pglist_data *pgdat, struct mem_cgroup *memc * abort proportional reclaim if either the file or anon lru has already * dropped to zero at the first pass. */ - scan_adjusted = (global_reclaim(sc) && !current_is_kswapd() && + scan_adjusted = (!cgroup_reclaim(sc) && !current_is_kswapd() && sc->priority == DEF_PRIORITY); blk_start_plug(&plug); @@ -2853,7 +2851,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc) * Legacy memcg will stall in page writeback so avoid forcibly * stalling in wait_iff_congested(). */ - if (!global_reclaim(sc) && sane_reclaim(sc) && + if (cgroup_reclaim(sc) && writeback_throttling_sane(sc) && sc->nr.dirty && sc->nr.dirty == sc->nr.congested) set_memcg_congestion(pgdat, root, true); @@ -2948,7 +2946,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) * Take care memory controller reclaiming has small influence * to global LRU. */ - if (global_reclaim(sc)) { + if (!cgroup_reclaim(sc)) { if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL)) continue; @@ -3048,7 +3046,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, retry: delayacct_freepages_start(); - if (global_reclaim(sc)) + if (!cgroup_reclaim(sc)) __count_zid_vm_events(ALLOCSTALL, sc->reclaim_idx, 1); do {
Seven years after introducing the global_reclaim() function, I still have to double take when reading a callsite. I don't know how others do it, this is a terrible name. Invert the meaning and rename it to cgroup_reclaim(). [ After all, "global reclaim" is just regular reclaim invoked from the page allocator. It's reclaim on behalf of a cgroup limit that is a special case of reclaim, and should be explicit - not the reverse. ] sane_reclaim() isn't very descriptive either: it tests whether we can use the regular writeback throttling - available during regular page reclaim or cgroup2 limit reclaim - or need to use the broken wait_on_page_writeback() method. Use "writeback_throttling_sane()". Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> --- mm/vmscan.c | 38 ++++++++++++++++++-------------------- 1 file changed, 18 insertions(+), 20 deletions(-)