| Message ID | 20240809172618.2946790-1-shakeel.butt@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | memcg: replace memcg ID idr with xarray | expand |
On Fri, Aug 09, 2024 at 10:26:18AM -0700, Shakeel Butt wrote: > At the moment memcg IDs are managed through IDR which requires external > synchronization mechanisms and makes the allocation code a bit awkward. > Let's switch to xarray and make the code simpler. > > Suggested-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Sweet! Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
On Fri, Aug 09, 2024 at 10:26:18AM -0700, Shakeel Butt wrote: > At the moment memcg IDs are managed through IDR which requires external > synchronization mechanisms and makes the allocation code a bit awkward. > Let's switch to xarray and make the code simpler. > > Suggested-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Looks great. Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
On Fri, Aug 09, 2024 at 10:26:18AM -0700, Shakeel Butt wrote: > At the moment memcg IDs are managed through IDR which requires external > synchronization mechanisms and makes the allocation code a bit awkward. > Let's switch to xarray and make the code simpler. > > Suggested-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Nice. Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> On Aug 10, 2024, at 01:26, Shakeel Butt <shakeel.butt@linux.dev> wrote: > > At the moment memcg IDs are managed through IDR which requires external > synchronization mechanisms and makes the allocation code a bit awkward. > Let's switch to xarray and make the code simpler. > > Suggested-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Muchun Song <muchun.song@linux.dev> Thanks.
On Fri 09-08-24 10:26:18, Shakeel Butt wrote: > At the moment memcg IDs are managed through IDR which requires external > synchronization mechanisms and makes the allocation code a bit awkward. > Let's switch to xarray and make the code simpler. > > Suggested-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Neat! I was not aware of this feature of XArray. Is there any actual reason for idr to have its own implementation with XArray offering a better interface? Acked-by: Michal Hocko <mhocko@suse.com> Thanks! > --- > mm/memcontrol.c | 34 +++++++--------------------------- > 1 file changed, 7 insertions(+), 27 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index e1ffd2950393..b8e6b98485c6 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3363,29 +3363,12 @@ static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) > */ > > #define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1) > -static DEFINE_IDR(mem_cgroup_idr); > -static DEFINE_SPINLOCK(memcg_idr_lock); > - > -static int mem_cgroup_alloc_id(void) > -{ > - int ret; > - > - idr_preload(GFP_KERNEL); > - spin_lock(&memcg_idr_lock); > - ret = idr_alloc(&mem_cgroup_idr, NULL, 1, MEM_CGROUP_ID_MAX + 1, > - GFP_NOWAIT); > - spin_unlock(&memcg_idr_lock); > - idr_preload_end(); > - return ret; > -} > +static DEFINE_XARRAY_ALLOC1(mem_cgroup_ids); > > static void mem_cgroup_id_remove(struct mem_cgroup *memcg) > { > if (memcg->id.id > 0) { > - spin_lock(&memcg_idr_lock); > - idr_remove(&mem_cgroup_idr, memcg->id.id); > - spin_unlock(&memcg_idr_lock); > - > + xa_erase(&mem_cgroup_ids, memcg->id.id); > memcg->id.id = 0; > } > } > @@ -3420,7 +3403,7 @@ static inline void mem_cgroup_id_put(struct mem_cgroup *memcg) > struct mem_cgroup *mem_cgroup_from_id(unsigned short id) > { > WARN_ON_ONCE(!rcu_read_lock_held()); > - return idr_find(&mem_cgroup_idr, id); > + return xa_load(&mem_cgroup_ids, id); > } > > #ifdef CONFIG_SHRINKER_DEBUG > @@ -3519,11 +3502,10 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) > if (!memcg) > return ERR_PTR(error); > > - memcg->id.id = mem_cgroup_alloc_id(); > - if (memcg->id.id < 0) { > - error = memcg->id.id; > + error = xa_alloc(&mem_cgroup_ids, &memcg->id.id, NULL, > + XA_LIMIT(1, MEM_CGROUP_ID_MAX), GFP_KERNEL); > + if (error) > goto fail; > - } > > memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), > GFP_KERNEL_ACCOUNT); > @@ -3664,9 +3646,7 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css) > * publish it here at the end of onlining. This matches the > * regular ID destruction during offlining. > */ > - spin_lock(&memcg_idr_lock); > - idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); > - spin_unlock(&memcg_idr_lock); > + xa_store(&mem_cgroup_ids, memcg->id.id, memcg, GFP_KERNEL); > > return 0; > offline_kmem: > -- > 2.43.5 >
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e1ffd2950393..b8e6b98485c6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3363,29 +3363,12 @@ static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg) */ #define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1) -static DEFINE_IDR(mem_cgroup_idr); -static DEFINE_SPINLOCK(memcg_idr_lock); - -static int mem_cgroup_alloc_id(void) -{ - int ret; - - idr_preload(GFP_KERNEL); - spin_lock(&memcg_idr_lock); - ret = idr_alloc(&mem_cgroup_idr, NULL, 1, MEM_CGROUP_ID_MAX + 1, - GFP_NOWAIT); - spin_unlock(&memcg_idr_lock); - idr_preload_end(); - return ret; -} +static DEFINE_XARRAY_ALLOC1(mem_cgroup_ids); static void mem_cgroup_id_remove(struct mem_cgroup *memcg) { if (memcg->id.id > 0) { - spin_lock(&memcg_idr_lock); - idr_remove(&mem_cgroup_idr, memcg->id.id); - spin_unlock(&memcg_idr_lock); - + xa_erase(&mem_cgroup_ids, memcg->id.id); memcg->id.id = 0; } } @@ -3420,7 +3403,7 @@ static inline void mem_cgroup_id_put(struct mem_cgroup *memcg) struct mem_cgroup *mem_cgroup_from_id(unsigned short id) { WARN_ON_ONCE(!rcu_read_lock_held()); - return idr_find(&mem_cgroup_idr, id); + return xa_load(&mem_cgroup_ids, id); } #ifdef CONFIG_SHRINKER_DEBUG @@ -3519,11 +3502,10 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent) if (!memcg) return ERR_PTR(error); - memcg->id.id = mem_cgroup_alloc_id(); - if (memcg->id.id < 0) { - error = memcg->id.id; + error = xa_alloc(&mem_cgroup_ids, &memcg->id.id, NULL, + XA_LIMIT(1, MEM_CGROUP_ID_MAX), GFP_KERNEL); + if (error) goto fail; - } memcg->vmstats = kzalloc(sizeof(struct memcg_vmstats), GFP_KERNEL_ACCOUNT); @@ -3664,9 +3646,7 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css) * publish it here at the end of onlining. This matches the * regular ID destruction during offlining. */ - spin_lock(&memcg_idr_lock); - idr_replace(&mem_cgroup_idr, memcg, memcg->id.id); - spin_unlock(&memcg_idr_lock); + xa_store(&mem_cgroup_ids, memcg->id.id, memcg, GFP_KERNEL); return 0; offline_kmem:
At the moment memcg IDs are managed through IDR which requires external synchronization mechanisms and makes the allocation code a bit awkward. Let's switch to xarray and make the code simpler. Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> --- mm/memcontrol.c | 34 +++++++--------------------------- 1 file changed, 7 insertions(+), 27 deletions(-)