| Message ID | 20210127233345.339910-10-shy828301@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Make shrinker's nr_deferred memcg aware | expand |
On 1/28/21 12:33 AM, Yang Shi wrote: > Now nr_deferred is available on per memcg level for memcg aware shrinkers, so don't need > allocate shrinker->nr_deferred for such shrinkers anymore. > > The prealloc_memcg_shrinker() would return -ENOSYS if !CONFIG_MEMCG or memcg is disabled > by kernel command line, then shrinker's SHRINKER_MEMCG_AWARE flag would be cleared. > This makes the implementation of this patch simpler. > > Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> > @@ -525,8 +528,20 @@ unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone > */ > int prealloc_shrinker(struct shrinker *shrinker) > { > - unsigned int size = sizeof(*shrinker->nr_deferred); > + unsigned int size; > + int err; > + > + if (shrinker->flags & SHRINKER_MEMCG_AWARE) { > + err = prealloc_memcg_shrinker(shrinker); > + if (!err) > + return 0; Nit: this err == 0 case is covered below: > + if (err != -ENOSYS) > + return err; > + > + shrinker->flags &= ~SHRINKER_MEMCG_AWARE; > + } > > + size = sizeof(*shrinker->nr_deferred); > if (shrinker->flags & SHRINKER_NUMA_AWARE) > size *= nr_node_ids; >
On Fri, Jan 29, 2021 at 7:40 AM Vlastimil Babka <vbabka@suse.cz> wrote: > > On 1/28/21 12:33 AM, Yang Shi wrote: > > Now nr_deferred is available on per memcg level for memcg aware shrinkers, so don't need > > allocate shrinker->nr_deferred for such shrinkers anymore. > > > > The prealloc_memcg_shrinker() would return -ENOSYS if !CONFIG_MEMCG or memcg is disabled > > by kernel command line, then shrinker's SHRINKER_MEMCG_AWARE flag would be cleared. > > This makes the implementation of this patch simpler. > > > > Signed-off-by: Yang Shi <shy828301@gmail.com> > > Acked-by: Vlastimil Babka <vbabka@suse.cz> > > > @@ -525,8 +528,20 @@ unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone > > */ > > int prealloc_shrinker(struct shrinker *shrinker) > > { > > - unsigned int size = sizeof(*shrinker->nr_deferred); > > + unsigned int size; > > + int err; > > + > > + if (shrinker->flags & SHRINKER_MEMCG_AWARE) { > > + err = prealloc_memcg_shrinker(shrinker); > > + if (!err) > > + return 0; > > Nit: this err == 0 case is covered below: Aha, thanks. Will fix in v6. > > > + if (err != -ENOSYS) > > + return err; > > + > > + shrinker->flags &= ~SHRINKER_MEMCG_AWARE; > > + } > > > > + size = sizeof(*shrinker->nr_deferred); > > if (shrinker->flags & SHRINKER_NUMA_AWARE) > > size *= nr_node_ids; > >
diff --git a/mm/vmscan.c b/mm/vmscan.c index e1f8960f5cf6..0373d7619d7b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -332,6 +332,9 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker) { int id, ret = -ENOMEM; + if (mem_cgroup_disabled()) + return -ENOSYS; + down_write(&shrinker_rwsem); /* This may call shrinker, so it must use down_read_trylock() */ id = idr_alloc(&shrinker_idr, NULL, 0, 0, GFP_KERNEL); @@ -414,7 +417,7 @@ static bool writeback_throttling_sane(struct scan_control *sc) #else static int prealloc_memcg_shrinker(struct shrinker *shrinker) { - return 0; + return -ENOSYS; } static void unregister_memcg_shrinker(struct shrinker *shrinker) @@ -525,8 +528,20 @@ unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone */ int prealloc_shrinker(struct shrinker *shrinker) { - unsigned int size = sizeof(*shrinker->nr_deferred); + unsigned int size; + int err; + + if (shrinker->flags & SHRINKER_MEMCG_AWARE) { + err = prealloc_memcg_shrinker(shrinker); + if (!err) + return 0; + if (err != -ENOSYS) + return err; + + shrinker->flags &= ~SHRINKER_MEMCG_AWARE; + } + size = sizeof(*shrinker->nr_deferred); if (shrinker->flags & SHRINKER_NUMA_AWARE) size *= nr_node_ids; @@ -534,26 +549,14 @@ int prealloc_shrinker(struct shrinker *shrinker) if (!shrinker->nr_deferred) return -ENOMEM; - if (shrinker->flags & SHRINKER_MEMCG_AWARE) { - if (prealloc_memcg_shrinker(shrinker)) - goto free_deferred; - } return 0; - -free_deferred: - kfree(shrinker->nr_deferred); - shrinker->nr_deferred = NULL; - return -ENOMEM; } void free_prealloced_shrinker(struct shrinker *shrinker) { - if (!shrinker->nr_deferred) - return; - if (shrinker->flags & SHRINKER_MEMCG_AWARE) - unregister_memcg_shrinker(shrinker); + return unregister_memcg_shrinker(shrinker); kfree(shrinker->nr_deferred); shrinker->nr_deferred = NULL;
Now nr_deferred is available on per memcg level for memcg aware shrinkers, so don't need allocate shrinker->nr_deferred for such shrinkers anymore. The prealloc_memcg_shrinker() would return -ENOSYS if !CONFIG_MEMCG or memcg is disabled by kernel command line, then shrinker's SHRINKER_MEMCG_AWARE flag would be cleared. This makes the implementation of this patch simpler. Signed-off-by: Yang Shi <shy828301@gmail.com> --- mm/vmscan.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-)