| Message ID | 20230720070825.992023-8-yosryahmed@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | memory recharging for offline memcgs | expand |
On Thu, Jul 20, 2023 at 07:08:24AM +0000, Yosry Ahmed wrote: > Add a sysctl to enable/disable memory recharging for offline memcgs. Add > a config option to control whether or not it is enabled by default. > > Signed-off-by: Yosry Ahmed <yosryahmed@google.com> > --- > include/linux/memcontrol.h | 2 ++ > kernel/sysctl.c | 11 +++++++++++ > mm/Kconfig | 12 ++++++++++++ > mm/memcontrol.c | 9 ++++++++- > 4 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 59b653d4a76e..ae9f09ee90cb 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -60,6 +60,8 @@ struct mem_cgroup_reclaim_cookie { > > #ifdef CONFIG_MEMCG > > +extern int sysctl_recharge_offline_memcgs; > + > #define MEM_CGROUP_ID_SHIFT 16 > #define MEM_CGROUP_ID_MAX USHRT_MAX > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 354a2d294f52..1735d1d95652 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -2249,6 +2249,17 @@ static struct ctl_table vm_table[] = { > .extra2 = (void *)&mmap_rnd_compat_bits_max, > }, > #endif > +#ifdef CONFIG_MEMCG > + { > + .procname = "recharge_offline_memcgs", > + .data = &sysctl_recharge_offline_memcgs, > + .maxlen = sizeof(sysctl_recharge_offline_memcgs), > + .mode = 0644, > + .proc_handler = proc_dointvec_minmax, > + .extra1 = SYSCTL_ZERO, > + .extra2 = SYSCTL_ONE, > + }, > +#endif /* CONFIG_MEMCG */ > { } > }; Please don't add any more sysctls to kernel/sysctl.c, git log that file for a series of cleanups which show how to use your own and why we have been doing that cleanup. Luis
On Thu, Jul 20, 2023 at 11:13 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > On Thu, Jul 20, 2023 at 07:08:24AM +0000, Yosry Ahmed wrote: > > Add a sysctl to enable/disable memory recharging for offline memcgs. Add > > a config option to control whether or not it is enabled by default. > > > > Signed-off-by: Yosry Ahmed <yosryahmed@google.com> > > --- > > include/linux/memcontrol.h | 2 ++ > > kernel/sysctl.c | 11 +++++++++++ > > mm/Kconfig | 12 ++++++++++++ > > mm/memcontrol.c | 9 ++++++++- > > 4 files changed, 33 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > index 59b653d4a76e..ae9f09ee90cb 100644 > > --- a/include/linux/memcontrol.h > > +++ b/include/linux/memcontrol.h > > @@ -60,6 +60,8 @@ struct mem_cgroup_reclaim_cookie { > > > > #ifdef CONFIG_MEMCG > > > > +extern int sysctl_recharge_offline_memcgs; > > + > > #define MEM_CGROUP_ID_SHIFT 16 > > #define MEM_CGROUP_ID_MAX USHRT_MAX > > > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > > index 354a2d294f52..1735d1d95652 100644 > > --- a/kernel/sysctl.c > > +++ b/kernel/sysctl.c > > @@ -2249,6 +2249,17 @@ static struct ctl_table vm_table[] = { > > .extra2 = (void *)&mmap_rnd_compat_bits_max, > > }, > > #endif > > +#ifdef CONFIG_MEMCG > > + { > > + .procname = "recharge_offline_memcgs", > > + .data = &sysctl_recharge_offline_memcgs, > > + .maxlen = sizeof(sysctl_recharge_offline_memcgs), > > + .mode = 0644, > > + .proc_handler = proc_dointvec_minmax, > > + .extra1 = SYSCTL_ZERO, > > + .extra2 = SYSCTL_ONE, > > + }, > > +#endif /* CONFIG_MEMCG */ > > { } > > }; > > Please don't add any more sysctls to kernel/sysctl.c, git log that file > for a series of cleanups which show how to use your own and why we have > been doing that cleanup. Thanks for pointing this out, I definitely missed it. Will do that in the next version. I guess this will also reduce the reviewer churn if I won't be touching kernel/sysctl.c? > > Luis
On Thu, Jul 20, 2023 at 11:24:20AM -0700, Yosry Ahmed wrote: > On Thu, Jul 20, 2023 at 11:13 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > > > On Thu, Jul 20, 2023 at 07:08:24AM +0000, Yosry Ahmed wrote: > > > Add a sysctl to enable/disable memory recharging for offline memcgs. Add > > > a config option to control whether or not it is enabled by default. > > > > > > Signed-off-by: Yosry Ahmed <yosryahmed@google.com> > > > --- > > > include/linux/memcontrol.h | 2 ++ > > > kernel/sysctl.c | 11 +++++++++++ > > > mm/Kconfig | 12 ++++++++++++ > > > mm/memcontrol.c | 9 ++++++++- > > > 4 files changed, 33 insertions(+), 1 deletion(-) > > > > > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > > > index 59b653d4a76e..ae9f09ee90cb 100644 > > > --- a/include/linux/memcontrol.h > > > +++ b/include/linux/memcontrol.h > > > @@ -60,6 +60,8 @@ struct mem_cgroup_reclaim_cookie { > > > > > > #ifdef CONFIG_MEMCG > > > > > > +extern int sysctl_recharge_offline_memcgs; > > > + > > > #define MEM_CGROUP_ID_SHIFT 16 > > > #define MEM_CGROUP_ID_MAX USHRT_MAX > > > > > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > > > index 354a2d294f52..1735d1d95652 100644 > > > --- a/kernel/sysctl.c > > > +++ b/kernel/sysctl.c > > > @@ -2249,6 +2249,17 @@ static struct ctl_table vm_table[] = { > > > .extra2 = (void *)&mmap_rnd_compat_bits_max, > > > }, > > > #endif > > > +#ifdef CONFIG_MEMCG > > > + { > > > + .procname = "recharge_offline_memcgs", > > > + .data = &sysctl_recharge_offline_memcgs, > > > + .maxlen = sizeof(sysctl_recharge_offline_memcgs), > > > + .mode = 0644, > > > + .proc_handler = proc_dointvec_minmax, > > > + .extra1 = SYSCTL_ZERO, > > > + .extra2 = SYSCTL_ONE, > > > + }, > > > +#endif /* CONFIG_MEMCG */ > > > { } > > > }; > > > > Please don't add any more sysctls to kernel/sysctl.c, git log that file > > for a series of cleanups which show how to use your own and why we have > > been doing that cleanup. > > Thanks for pointing this out, I definitely missed it. Will do that in > the next version. I guess this will also reduce the reviewer churn if > I won't be touching kernel/sysctl.c? Right, it means I don't have to care anymore about random sysctl knobs. Let people knob it all up. Luis
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 59b653d4a76e..ae9f09ee90cb 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -60,6 +60,8 @@ struct mem_cgroup_reclaim_cookie { #ifdef CONFIG_MEMCG +extern int sysctl_recharge_offline_memcgs; + #define MEM_CGROUP_ID_SHIFT 16 #define MEM_CGROUP_ID_MAX USHRT_MAX diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 354a2d294f52..1735d1d95652 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2249,6 +2249,17 @@ static struct ctl_table vm_table[] = { .extra2 = (void *)&mmap_rnd_compat_bits_max, }, #endif +#ifdef CONFIG_MEMCG + { + .procname = "recharge_offline_memcgs", + .data = &sysctl_recharge_offline_memcgs, + .maxlen = sizeof(sysctl_recharge_offline_memcgs), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, +#endif /* CONFIG_MEMCG */ { } }; diff --git a/mm/Kconfig b/mm/Kconfig index 09130434e30d..9462c4b598d9 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1236,6 +1236,18 @@ config LOCK_MM_AND_FIND_VMA bool depends on !STACK_GROWSUP +config MEMCG_RECHARGE_OFFLINE_ENABLED + bool "Recharge memory charged to offline memcgs" + depends on MEMCG + help + When a memory cgroup is removed by userspace, try to recharge any + memory still charged to it to avoid having it live on as an offline + memcg. Offline memcgs potentially consume memory and limit scalability + of some operations. + + This option enables the above behavior by default. It can be override + at runtime through /proc/sys/vm/recharge_offline_memcgs. + source "mm/damon/Kconfig" endmenu diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2fe9c6f1be80..25cdb17eaaa3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -96,6 +96,9 @@ static bool cgroup_memory_nobpf __ro_after_init; static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); #endif +int sysctl_recharge_offline_memcgs __read_mostly = IS_ENABLED( + CONFIG_MEMCG_RECHARGE_OFFLINE_ENABLED); + static struct workqueue_struct *memcg_recharge_wq; /* Whether legacy memory+swap accounting is active */ @@ -6592,7 +6595,8 @@ static void memcg_recharge_mapped_folios(struct mem_cgroup *memcg) INIT_DELAYED_WORK(&memcg->recharge_mapped_work.dwork, memcg_do_recharge_mapped_folios); - if (memcg_recharge_wq && memcg_nr_local_mapped_pages(memcg)) { + if (sysctl_recharge_offline_memcgs && + memcg_recharge_wq && memcg_nr_local_mapped_pages(memcg)) { memcg->recharge_mapped_work.retries = 0; queue_delayed_work(memcg_recharge_wq, &memcg->recharge_mapped_work.dwork, 0); @@ -6605,6 +6609,9 @@ static bool should_do_deferred_recharge(struct folio *folio) struct mem_cgroup *memcg; bool ret; + if (!sysctl_recharge_offline_memcgs) + return false; + rcu_read_lock(); memcg = folio_memcg_rcu(folio); ret = memcg && !!(memcg->css.flags & CSS_DYING);
Add a sysctl to enable/disable memory recharging for offline memcgs. Add a config option to control whether or not it is enabled by default. Signed-off-by: Yosry Ahmed <yosryahmed@google.com> --- include/linux/memcontrol.h | 2 ++ kernel/sysctl.c | 11 +++++++++++ mm/Kconfig | 12 ++++++++++++ mm/memcontrol.c | 9 ++++++++- 4 files changed, 33 insertions(+), 1 deletion(-)