Message-ID: <4FD6F3DD.2070004@jp.fujitsu.com>
Date:	Tue, 12 Jun 2012 16:46:37 +0900
From:	Kamezawa Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
CC:	linux-mm@...ck.org, dhillf@...il.com, rientjes@...gle.com,
	mhocko@...e.cz, akpm@...ux-foundation.org, hannes@...xchg.org,
	linux-kernel@...r.kernel.org, cgroups@...r.kernel.org
Subject: Re: [PATCH -V8 09/16] mm/hugetlb: Add new HugeTLB cgroup

(2012/06/09 17:59), Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V"<aneesh.kumar@...ux.vnet.ibm.com>
> 
> This patch implements a new controller that allows us to control HugeTLB
> allocations. The extension allows to limit the HugeTLB usage per control
> group and enforces the controller limit during page fault.  Since HugeTLB
> doesn't support page reclaim, enforcing the limit at page fault time implies
> that, the application will get SIGBUS signal if it tries to access HugeTLB
> pages beyond its limit. This requires the application to know beforehand
> how much HugeTLB pages it would require for its use.
> 
> The charge/uncharge calls will be added to HugeTLB code in later patch.
> Support for cgroup removal will be added in later patches.
> 
> Signed-off-by: Aneesh Kumar K.V<aneesh.kumar@...ux.vnet.ibm.com>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>

some nitpick below.

> ---
>   include/linux/cgroup_subsys.h  |    6 +++
>   include/linux/hugetlb_cgroup.h |   79 ++++++++++++++++++++++++++++
>   init/Kconfig                   |   16 ++++++
>   mm/Makefile                    |    1 +
>   mm/hugetlb_cgroup.c            |  114 ++++++++++++++++++++++++++++++++++++++++
>   5 files changed, 216 insertions(+)
>   create mode 100644 include/linux/hugetlb_cgroup.h
>   create mode 100644 mm/hugetlb_cgroup.c
> 
> diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
> index 0bd390c..895923a 100644
> --- a/include/linux/cgroup_subsys.h
> +++ b/include/linux/cgroup_subsys.h
> @@ -72,3 +72,9 @@ SUBSYS(net_prio)
>   #endif
> 
>   /* */
> +
> +#ifdef CONFIG_CGROUP_HUGETLB_RES_CTLR
> +SUBSYS(hugetlb)
> +#endif
> +
> +/* */
> diff --git a/include/linux/hugetlb_cgroup.h b/include/linux/hugetlb_cgroup.h
> new file mode 100644
> index 0000000..5794be4
> --- /dev/null
> +++ b/include/linux/hugetlb_cgroup.h
> @@ -0,0 +1,79 @@
> +/*
> + * Copyright IBM Corporation, 2012
> + * Author Aneesh Kumar K.V<aneesh.kumar@...ux.vnet.ibm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of version 2.1 of the GNU Lesser General Public License
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + *
> + */
> +
> +#ifndef _LINUX_HUGETLB_CGROUP_H
> +#define _LINUX_HUGETLB_CGROUP_H
> +
> +#include<linux/res_counter.h>
> +
> +struct hugetlb_cgroup {
> +	struct cgroup_subsys_state css;
> +	/*
> +	 * the counter to account for hugepages from hugetlb.
> +	 */
> +	struct res_counter hugepage[HUGE_MAX_HSTATE];
> +};
> +
> +#ifdef CONFIG_CGROUP_HUGETLB_RES_CTLR
> +static inline bool hugetlb_cgroup_disabled(void)
> +{
> +	if (hugetlb_subsys.disabled)
> +		return true;
> +	return false;
> +}
> +
> +extern int hugetlb_cgroup_charge_page(int idx, unsigned long nr_pages,
> +				      struct hugetlb_cgroup **ptr);
> +extern void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
> +					 struct hugetlb_cgroup *h_cg,
> +					 struct page *page);
> +extern void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
> +					 struct page *page);
> +extern void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
> +					   struct hugetlb_cgroup *h_cg);
> +#else
> +static inline bool hugetlb_cgroup_disabled(void)
> +{
> +	return true;
> +}
> +
> +static inline int
> +hugetlb_cgroup_charge_page(int idx, unsigned long nr_pages,
> +			   struct hugetlb_cgroup **ptr)
> +{
> +	return 0;
> +}
> +
> +static inline void
> +hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
> +			     struct hugetlb_cgroup *h_cg,
> +			     struct page *page)
> +{
> +	return;
> +}
> +
> +static inline void
> +hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page)
> +{
> +	return;
> +}
> +
> +static inline void
> +hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
> +			       struct hugetlb_cgroup *h_cg)
> +{
> +	return;
> +}
> +#endif  /* CONFIG_MEM_RES_CTLR_HUGETLB */
> +#endif
> diff --git a/init/Kconfig b/init/Kconfig
> index d07dcf9..b9a0d0a 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -751,6 +751,22 @@ config CGROUP_MEM_RES_CTLR_KMEM
>   	  the kmem extension can use it to guarantee that no group of processes
>   	  will ever exhaust kernel resources alone.
> 
> +config CGROUP_HUGETLB_RES_CTLR
> +	bool "HugeTLB Resource Controller for Control Groups"
> +	depends on RESOURCE_COUNTERS&&  HUGETLB_PAGE&&  EXPERIMENTAL
> +	select PAGE_CGROUP
> +	default n
> +	help
> +	  Provides a simple cgroup Resource Controller for HugeTLB pages.

what you want to say by adding 'simple' here ?


> +	  When you enable this, you can put a per cgroup limit on HugeTLB usage.
> +	  The limit is enforced during page fault. Since HugeTLB doesn't
> +	  support page reclaim, enforcing the limit at page fault time implies
> +	  that, the application will get SIGBUS signal if it tries to access
> +	  HugeTLB pages beyond its limit. This requires the application to know
> +	  beforehand how much HugeTLB pages it would require for its use. The
> +	  control group is tracked in the third page lru pointer. This means
> +	  that we cannot use the controller with huge page less than 3 pages.
> +
>   config CGROUP_PERF
>   	bool "Enable perf_event per-cpu per-container group (cgroup) monitoring"
>   	depends on PERF_EVENTS&&  CGROUPS
> diff --git a/mm/Makefile b/mm/Makefile
> index a156285..a8dd8d5 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_MIGRATION) += migrate.o
>   obj-$(CONFIG_QUICKLIST) += quicklist.o
>   obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
>   obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
> +obj-$(CONFIG_CGROUP_HUGETLB_RES_CTLR) += hugetlb_cgroup.o
>   obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
>   obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
>   obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> new file mode 100644
> index 0000000..20a32c5
> --- /dev/null
> +++ b/mm/hugetlb_cgroup.c
> @@ -0,0 +1,114 @@
> +/*
> + *
> + * Copyright IBM Corporation, 2012
> + * Author Aneesh Kumar K.V<aneesh.kumar@...ux.vnet.ibm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of version 2.1 of the GNU Lesser General Public License
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + *
> + */
> +
> +#include<linux/cgroup.h>
> +#include<linux/slab.h>
> +#include<linux/hugetlb.h>
> +#include<linux/hugetlb_cgroup.h>
> +
> +struct cgroup_subsys hugetlb_subsys __read_mostly;
> +struct hugetlb_cgroup *root_h_cgroup __read_mostly;
> +
> +static inline
> +struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
> +{
> +	if (s)
> +		return container_of(s, struct hugetlb_cgroup, css);
> +	return NULL;
> +}
> +
> +static inline
> +struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup)
> +{
> +	return hugetlb_cgroup_from_css(cgroup_subsys_state(cgroup,
> +							   hugetlb_subsys_id));
> +}
> +
> +static inline
> +struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
> +{
> +	return hugetlb_cgroup_from_css(task_subsys_state(task,
> +							 hugetlb_subsys_id));
> +}
> +
> +static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
> +{
> +	return (h_cg == root_h_cgroup);
> +}
> +
> +static inline struct hugetlb_cgroup *parent_hugetlb_cgroup(struct cgroup *cg)
> +{
> +	if (!cg->parent)
> +		return NULL;
> +	return hugetlb_cgroup_from_cgroup(cg->parent);
> +}
> +
> +static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
> +{
> +	int idx;
> +	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
> +
> +	for (idx = 0; idx<  hugetlb_max_hstate; idx++) {
> +		if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE))>  0)
> +			return 1;
> +	}
> +	return 0;
> +}

How about using true/false rather than 0/1 ?


> +
> +static struct cgroup_subsys_state *hugetlb_cgroup_create(struct cgroup *cgroup)
> +{
> +	int idx;
> +	struct cgroup *parent_cgroup;
> +	struct hugetlb_cgroup *h_cgroup, *parent_h_cgroup;
> +
> +	h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
> +	if (!h_cgroup)
> +		return ERR_PTR(-ENOMEM);
> +
> +	parent_cgroup = cgroup->parent;
> +	if (parent_cgroup) {
> +		parent_h_cgroup = hugetlb_cgroup_from_cgroup(parent_cgroup);
> +		for (idx = 0; idx<  HUGE_MAX_HSTATE; idx++)
                                ^^^
add space is better.

> +			res_counter_init(&h_cgroup->hugepage[idx],
> +					&parent_h_cgroup->hugepage[idx]);
> +	} else {
> +		root_h_cgroup = h_cgroup;
> +		for (idx = 0; idx<  HUGE_MAX_HSTATE; idx++)
                                ^^^

> +			res_counter_init(&h_cgroup->hugepage[idx], NULL);
> +	}
> +	return&h_cgroup->css;
             ^^^
ditto.

> +}
> +
> +static void hugetlb_cgroup_destroy(struct cgroup *cgroup)
> +{
> +	struct hugetlb_cgroup *h_cgroup;
> +
> +	h_cgroup = hugetlb_cgroup_from_cgroup(cgroup);
> +	kfree(h_cgroup);
> +}
> +
> +static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
> +{
> +	/* We will add the cgroup removal support in later patches */
> +	   return -EBUSY;
> +}

-ENOTSUP rather than -BUSY :p

> +
> +struct cgroup_subsys hugetlb_subsys = {
> +	.name = "hugetlb",
> +	.create     = hugetlb_cgroup_create,
> +	.pre_destroy = hugetlb_cgroup_pre_destroy,
> +	.destroy    = hugetlb_cgroup_destroy,
> +	.subsys_id  = hugetlb_subsys_id,
> +};


Thanks,
-Kame

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