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Date: Fri, 13 Jun 2008 18:34:02 +0900 From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> Cc: "linux-mm@...ck.org" <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>, "menage@...gle.com" <menage@...gle.com>, "balbir@...ux.vnet.ibm.com" <balbir@...ux.vnet.ibm.com>, "xemul@...nvz.org" <xemul@...nvz.org>, "yamamoto@...inux.co.jp" <yamamoto@...inux.co.jp>, "nishimura@....nes.nec.co.jp" <nishimura@....nes.nec.co.jp>, "lizf@...fujitsu.com" <lizf@...fujitsu.com> Subject: [PATCH 4/6] res_counter: basic hierarchy support Add a hierarhy support to res_counter. This patch itself just supports "No Hierarchy" hierarchy, as a default/basic hierarchy system. Changelog: v3 -> v4. - cut out from hardwall hierarchy patch set. - just support "No hierarchy" model. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> --- Documentation/controllers/resource_counter.txt | 27 +++++- include/linux/res_counter.h | 15 +++ kernel/res_counter.c | 107 ++++++++++++++++++++----- mm/memcontrol.c | 1 4 files changed, 129 insertions(+), 21 deletions(-) Index: linux-2.6.26-rc5-mm3/include/linux/res_counter.h =================================================================== --- linux-2.6.26-rc5-mm3.orig/include/linux/res_counter.h +++ linux-2.6.26-rc5-mm3/include/linux/res_counter.h @@ -21,8 +21,13 @@ * the helpers described beyond */ +enum res_cont_hierarchy_model { + RES_CONT_NO_HIERARCHY, +}; + struct res_counter; struct res_counter_ops { + enum res_cont_hierarchy_model hierarchy_model; /* called when the subsystem has to reduce the usage. */ int (*shrink_usage)(struct res_counter *cnt, unsigned long long val, int retry_count); @@ -46,6 +51,10 @@ struct res_counter { */ unsigned long long failcnt; /* + * parent of this counter in hierarchy. if root, this is NULL. + */ + struct res_counter *parent; + /* * registered callbacks etc...for res_counter. */ struct res_counter_ops ops; @@ -101,6 +110,12 @@ static inline void res_counter_init(stru res_counter_init_ops(counter, NULL); } +void res_counter_init_hierarchy(struct res_counter *counter, + struct res_counter *parent); + +int res_counter_set_ops(struct res_counter *counter, + struct res_counter_ops *ops); + /* * charge - try to consume more resource. * Index: linux-2.6.26-rc5-mm3/kernel/res_counter.c =================================================================== --- linux-2.6.26-rc5-mm3.orig/kernel/res_counter.c +++ linux-2.6.26-rc5-mm3/kernel/res_counter.c @@ -30,8 +30,70 @@ void res_counter_init_ops(struct res_cou counter->limit = (unsigned long long)LLONG_MAX; if (ops) counter->ops = *ops; + counter->parent = NULL; +} + +void __res_counter_init_hierarchy_core(struct res_counter *counter) +{ + switch (counter->ops.hierarchy_model) { + case RES_CONT_NO_HIERARCHY: + counter->limit = (unsigned long long)LLONG_MAX; + break; + default: + break; + } + return; +} + + +/** + * res_counter_init_hierarchy() -- initialize res_counter under some hierarchy. + * @counter: a counter will be initialized. + * @parent: parent of counter. + * + * parent->ops is copied to counter->ops and counter will be initialized + * to be suitable style for the hierarchy model. + */ +void res_counter_init_hierarchy(struct res_counter *counter, + struct res_counter *parent) +{ + struct res_counter_ops *ops = NULL; + + if (parent) + ops = &parent->ops; + res_counter_init_ops(counter, ops); + counter->parent = parent; + + __res_counter_init_hierarchy_core(counter); } +/** + * res_counter_set_ops() -- reset res->counter.ops to be passed ops. + * @coutner: a counter to be set ops. + * @ops: res_counter_ops + * + * This operations is allowed only when there is no parent or parent's + * hierarchy_model == RES_CONT_NO_HIERARCHY. returns 0 at success. + */ + +int res_counter_set_ops(struct res_counter *counter, + struct res_counter_ops *ops) +{ + struct res_counter *parent; + /* + * This operation is allowed only when parents's hierarchy + * is NO_HIERARCHY or this is ROOT. + */ + parent = counter->parent; + if (parent && parent->ops.hierarchy_model != RES_CONT_NO_HIERARCHY) + return -EINVAL; + + counter->ops = *ops; + + return 0; +} + + int res_counter_charge_locked(struct res_counter *counter, unsigned long val) { if (counter->usage + val > counter->limit) { @@ -125,30 +187,39 @@ static int res_counter_resize_limit(stru int retry_count = 0; int ret = -EBUSY; unsigned long flags; + enum model = RES_CONT_NO_HIERARCHY; BUG_ON(!cnt->ops.shrink_usage); - while (1) { - spin_lock_irqsave(&cnt->lock, flags); - if (cnt->usage <= val) { - cnt->limit = val; - ret = 0; - spin_unlock_irqrestore(&cnt->lock, flags); - break; - } - BUG_ON(val > cnt->limit); - spin_unlock_irqrestore(&cnt->lock, flags); + switch (model) { + case RES_CONT_NO_HIERARCHY: /* - * Rest before calling callback().... rest after callback - * tends to add difference between the result of callback and - * the check in next loop. + * shrink usage to be below the new limit. */ - cond_resched(); + while (1) { + spin_lock_irqsave(&cnt->lock, flags); + if (cnt->usage <= val) { + cnt->limit = val; + ret = 0; + } + spin_unlock_irqrestore(&cnt->lock, flags); + if (!ret) + break; + /* + * Rest before calling callback().... rest after + * callback tends to add difference between the result + * of callback and the check in next loop. + */ + cond_resched(); - ret = cnt->ops.shrink_usage(cnt, val, retry_count); - if (!ret) - break; - retry_count++; + ret = cnt->ops.shrink_usage(cnt, val, retry_count); + if (!ret) + break; + retry_count++; + } + break; + default: + BUG(); } return ret; } Index: linux-2.6.26-rc5-mm3/Documentation/controllers/resource_counter.txt =================================================================== --- linux-2.6.26-rc5-mm3.orig/Documentation/controllers/resource_counter.txt +++ linux-2.6.26-rc5-mm3/Documentation/controllers/resource_counter.txt @@ -39,11 +39,14 @@ to work with it. The failcnt stands for "failures counter". This is the number of resource allocation attempts that failed. - e. res_counter_ops. + e. parent + parent of this res_counter under hierarchy. + + f. res_counter_ops. Callbacks for helping resource_counter per each subsystem. - shrink_usage() .... called at limit change (decrease). - f. spinlock_t lock + g. spinlock_t lock Protects changes of the above values. @@ -157,7 +160,25 @@ counter fields. They are recommended to Returns 0 at success. Any error code is acceptable but -EBUSY will be suitable to show "the kernel can't shrink usage." -6. Usage example +6. Hierarchy + + Groups of res_counter can be controlled under some tree (cgroup tree). + Taking the tree into account, res_counter can be under some hierarchical + control. THe res_counter itself supports hierarchy_model and calls + registered callbacks at suitable events. + + For keeping sanity of hierarchy, hierarchy_model of a res_counter can be + changed when parent's hierarchy_model is RES_CONT_NO_HIERARCHY. + res_counter doesn't count # of children by itself but some subysystem should + be aware that it has no children if necessary. + (don't want to fully duplicate cgroup's hierarchy. Cost of remembering parent + is cheap.) + + a. Independent hierarchy (RES_CONT_NO_HIERARCHY) model + This is no relationship between parent and children. + + +7. Usage example a. Declare a task group (take a look at cgroups subsystem for this) and fold a res_counter into it Index: linux-2.6.26-rc5-mm3/mm/memcontrol.c =================================================================== --- linux-2.6.26-rc5-mm3.orig/mm/memcontrol.c +++ linux-2.6.26-rc5-mm3/mm/memcontrol.c @@ -1086,6 +1086,7 @@ static void mem_cgroup_free(struct mem_c } struct res_counter_ops root_ops = { + .hierarchy_model = RES_CONT_NO_HIERARCHY, .shrink_usage = mem_cgroup_shrink_usage_to, }; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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