| Message ID | 20210209174646.1310591-10-shy828301@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v7,01/12] mm: vmscan: use nid from shrink_control for tracepoint | expand |
On Tue, Feb 09, 2021 at 09:46:43AM -0800, Yang Shi wrote: > Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred > will be used in the following cases: > 1. Non memcg aware shrinkers > 2. !CONFIG_MEMCG > 3. memcg is disabled by boot parameter > > Signed-off-by: Yang Shi <shy828301@gmail.com> > --- > mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 66 insertions(+), 12 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index d4b030a0b2a9..748aa6e90f83 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -368,6 +368,24 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > up_write(&shrinker_rwsem); > } > > +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, > + struct mem_cgroup *memcg) "Count" is not associated with xchg() semantics in my head, but I don't know what's the better version. Maybe steal or pop? Otherwise the patch looks good to me. Thanks!
On Tue, Feb 9, 2021 at 5:27 PM Roman Gushchin <guro@fb.com> wrote: > > On Tue, Feb 09, 2021 at 09:46:43AM -0800, Yang Shi wrote: > > Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred > > will be used in the following cases: > > 1. Non memcg aware shrinkers > > 2. !CONFIG_MEMCG > > 3. memcg is disabled by boot parameter > > > > Signed-off-by: Yang Shi <shy828301@gmail.com> > > --- > > mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++++++++++--------- > > 1 file changed, 66 insertions(+), 12 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index d4b030a0b2a9..748aa6e90f83 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -368,6 +368,24 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > > up_write(&shrinker_rwsem); > > } > > > > +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, > > + struct mem_cgroup *memcg) > > "Count" is not associated with xchg() semantics in my head, but I don't know > what's the better version. Maybe steal or pop? It is used to retrieve the nr_deferred value. I don't think "steal" or "pop" helps understand. Actually "count" is borrowed from count_objects() method of shrinker. > > Otherwise the patch looks good to me. > > Thanks!
On 10.02.2021 04:52, Yang Shi wrote: > On Tue, Feb 9, 2021 at 5:27 PM Roman Gushchin <guro@fb.com> wrote: >> >> On Tue, Feb 09, 2021 at 09:46:43AM -0800, Yang Shi wrote: >>> Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred >>> will be used in the following cases: >>> 1. Non memcg aware shrinkers >>> 2. !CONFIG_MEMCG >>> 3. memcg is disabled by boot parameter >>> >>> Signed-off-by: Yang Shi <shy828301@gmail.com> >>> --- >>> mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++++++++++--------- >>> 1 file changed, 66 insertions(+), 12 deletions(-) >>> >>> diff --git a/mm/vmscan.c b/mm/vmscan.c >>> index d4b030a0b2a9..748aa6e90f83 100644 >>> --- a/mm/vmscan.c >>> +++ b/mm/vmscan.c >>> @@ -368,6 +368,24 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) >>> up_write(&shrinker_rwsem); >>> } >>> >>> +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, >>> + struct mem_cgroup *memcg) >> >> "Count" is not associated with xchg() semantics in my head, but I don't know >> what's the better version. Maybe steal or pop? > > It is used to retrieve the nr_deferred value. I don't think "steal" or > "pop" helps understand. Actually "count" is borrowed from > count_objects() method of shrinker. I'd also voted for another name. xchg_nr_deferred() or steal/pop sound better for me.
On Wed, Feb 10, 2021 at 6:37 AM Kirill Tkhai <ktkhai@virtuozzo.com> wrote: > > On 10.02.2021 04:52, Yang Shi wrote: > > On Tue, Feb 9, 2021 at 5:27 PM Roman Gushchin <guro@fb.com> wrote: > >> > >> On Tue, Feb 09, 2021 at 09:46:43AM -0800, Yang Shi wrote: > >>> Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred > >>> will be used in the following cases: > >>> 1. Non memcg aware shrinkers > >>> 2. !CONFIG_MEMCG > >>> 3. memcg is disabled by boot parameter > >>> > >>> Signed-off-by: Yang Shi <shy828301@gmail.com> > >>> --- > >>> mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++++++++++--------- > >>> 1 file changed, 66 insertions(+), 12 deletions(-) > >>> > >>> diff --git a/mm/vmscan.c b/mm/vmscan.c > >>> index d4b030a0b2a9..748aa6e90f83 100644 > >>> --- a/mm/vmscan.c > >>> +++ b/mm/vmscan.c > >>> @@ -368,6 +368,24 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > >>> up_write(&shrinker_rwsem); > >>> } > >>> > >>> +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, > >>> + struct mem_cgroup *memcg) > >> > >> "Count" is not associated with xchg() semantics in my head, but I don't know > >> what's the better version. Maybe steal or pop? > > > > It is used to retrieve the nr_deferred value. I don't think "steal" or > > "pop" helps understand. Actually "count" is borrowed from > > count_objects() method of shrinker. > > I'd also voted for another name. > > xchg_nr_deferred() or steal/pop sound better for me. OK, I do have a hard time to understand steal/pop, but xchg sounds more self-explained to me. >
diff --git a/mm/vmscan.c b/mm/vmscan.c index d4b030a0b2a9..748aa6e90f83 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -368,6 +368,24 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) up_write(&shrinker_rwsem); } +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, + struct mem_cgroup *memcg) +{ + struct shrinker_info *info; + + info = shrinker_info_protected(memcg, nid); + return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0); +} + +static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker, + struct mem_cgroup *memcg) +{ + struct shrinker_info *info; + + info = shrinker_info_protected(memcg, nid); + return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]); +} + static bool cgroup_reclaim(struct scan_control *sc) { return sc->target_mem_cgroup; @@ -406,6 +424,18 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) { } +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, + struct mem_cgroup *memcg) +{ + return 0; +} + +static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker, + struct mem_cgroup *memcg) +{ + return 0; +} + static bool cgroup_reclaim(struct scan_control *sc) { return false; @@ -417,6 +447,39 @@ static bool writeback_throttling_sane(struct scan_control *sc) } #endif +static long count_nr_deferred(struct shrinker *shrinker, + struct shrink_control *sc) +{ + int nid = sc->nid; + + if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) + nid = 0; + + if (sc->memcg && + (shrinker->flags & SHRINKER_MEMCG_AWARE)) + return count_nr_deferred_memcg(nid, shrinker, + sc->memcg); + + return atomic_long_xchg(&shrinker->nr_deferred[nid], 0); +} + + +static long add_nr_deferred(long nr, struct shrinker *shrinker, + struct shrink_control *sc) +{ + int nid = sc->nid; + + if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) + nid = 0; + + if (sc->memcg && + (shrinker->flags & SHRINKER_MEMCG_AWARE)) + return add_nr_deferred_memcg(nr, nid, shrinker, + sc->memcg); + + return atomic_long_add_return(nr, &shrinker->nr_deferred[nid]); +} + /* * This misses isolated pages which are not accounted for to save counters. * As the data only determines if reclaim or compaction continues, it is @@ -549,14 +612,10 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, long freeable; long nr; long new_nr; - int nid = shrinkctl->nid; long batch_size = shrinker->batch ? shrinker->batch : SHRINK_BATCH; long scanned = 0, next_deferred; - if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) - nid = 0; - freeable = shrinker->count_objects(shrinker, shrinkctl); if (freeable == 0 || freeable == SHRINK_EMPTY) return freeable; @@ -566,7 +625,7 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, * and zero it so that other concurrent shrinker invocations * don't also do this scanning work. */ - nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0); + nr = count_nr_deferred(shrinker, shrinkctl); total_scan = nr; if (shrinker->seeks) { @@ -657,14 +716,9 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, next_deferred = 0; /* * move the unused scan count back into the shrinker in a - * manner that handles concurrent updates. If we exhausted the - * scan, there is no need to do an update. + * manner that handles concurrent updates. */ - if (next_deferred > 0) - new_nr = atomic_long_add_return(next_deferred, - &shrinker->nr_deferred[nid]); - else - new_nr = atomic_long_read(&shrinker->nr_deferred[nid]); + new_nr = add_nr_deferred(next_deferred, shrinker, shrinkctl); trace_mm_shrink_slab_end(shrinker, shrinkctl->nid, freed, nr, new_nr, total_scan); return freed;
Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred will be used in the following cases: 1. Non memcg aware shrinkers 2. !CONFIG_MEMCG 3. memcg is disabled by boot parameter Signed-off-by: Yang Shi <shy828301@gmail.com> --- mm/vmscan.c | 78 ++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 66 insertions(+), 12 deletions(-)