From 8af01f56a03e9cbd91a55d688fce1315021efba8 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Aug 2013 20:11:22 -0400 Subject: cgroup: s/cgroup_subsys_state/cgroup_css/ s/task_subsys_state/task_css/ The names of the two struct cgroup_subsys_state accessors - cgroup_subsys_state() and task_subsys_state() - are somewhat awkward. The former clashes with the type name and the latter doesn't even indicate it's somehow related to cgroup. We're about to revamp large portion of cgroup API, so, let's rename them so that they're less awkward. Most per-controller usages of the accessors are localized in accessor wrappers and given the amount of scheduled changes, this isn't gonna add any noticeable headache. Rename cgroup_subsys_state() to cgroup_css() and task_subsys_state() to task_css(). This patch is pure rename. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- mm/hugetlb_cgroup.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'mm/hugetlb_cgroup.c') diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index 9cea7de22ffb..50f213fc52c7 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -42,15 +42,13 @@ struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s) static inline struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup) { - return hugetlb_cgroup_from_css(cgroup_subsys_state(cgroup, - hugetlb_subsys_id)); + return hugetlb_cgroup_from_css(cgroup_css(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)); + return hugetlb_cgroup_from_css(task_css(task, hugetlb_subsys_id)); } static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg) -- cgit v1.2.3 From 3f79851831a135c5cebbcaa8cddb07d02870b069 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Aug 2013 20:11:22 -0400 Subject: hugetlb_cgroup: pass around @hugetlb_cgroup instead of @cgroup cgroup controller API will be converted to primarily use struct cgroup_subsys_state instead of struct cgroup. In preparation, make hugetlb_cgroup functions pass around struct hugetlb_cgroup instead of struct cgroup. This patch shouldn't cause any behavior differences. Signed-off-by: Tejun Heo Acked-by: Li Zefan Reviewed-by: Aneesh Kumar K.V Reviewed-by: Michal Hocko Cc: KAMEZAWA Hiroyuki Cc: Johannes Weiner --- mm/hugetlb_cgroup.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'mm/hugetlb_cgroup.c') diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index 50f213fc52c7..d2f9fc0b186e 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -56,17 +56,19 @@ 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) +static inline struct hugetlb_cgroup * +parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg) { - if (!cg->parent) + struct cgroup *parent = h_cg->css.cgroup->parent; + + if (!parent) return NULL; - return hugetlb_cgroup_from_cgroup(cg->parent); + return hugetlb_cgroup_from_cgroup(parent); } -static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg) +static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_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) @@ -115,15 +117,14 @@ static void hugetlb_cgroup_css_free(struct cgroup *cgroup) * page reference and test for page active here. This function * cannot fail. */ -static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup, +static void hugetlb_cgroup_move_parent(int idx, struct hugetlb_cgroup *h_cg, struct page *page) { int csize; struct res_counter *counter; struct res_counter *fail_res; struct hugetlb_cgroup *page_hcg; - struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); - struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup); + struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg); page_hcg = hugetlb_cgroup_from_page(page); /* @@ -155,6 +156,7 @@ out: */ static void hugetlb_cgroup_css_offline(struct cgroup *cgroup) { + struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); struct hstate *h; struct page *page; int idx = 0; @@ -163,13 +165,13 @@ static void hugetlb_cgroup_css_offline(struct cgroup *cgroup) for_each_hstate(h) { spin_lock(&hugetlb_lock); list_for_each_entry(page, &h->hugepage_activelist, lru) - hugetlb_cgroup_move_parent(idx, cgroup, page); + hugetlb_cgroup_move_parent(idx, h_cg, page); spin_unlock(&hugetlb_lock); idx++; } cond_resched(); - } while (hugetlb_cgroup_have_usage(cgroup)); + } while (hugetlb_cgroup_have_usage(h_cg)); } int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, -- cgit v1.2.3 From a7c6d554aa01236ac2a9f851ab0f75704f76dfa2 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Aug 2013 20:11:23 -0400 Subject: cgroup: add/update accessors which obtain subsys specific data from css css (cgroup_subsys_state) is usually embedded in a subsys specific data structure. Subsystems either use container_of() directly to cast from css to such data structure or has an accessor function wrapping such cast. As cgroup as whole is moving towards using css as the main interface handle, add and update such accessors to ease dealing with css's. All accessors explicitly handle NULL input and return NULL in those cases. While this looks like an extra branch in the code, as all controllers specific data structures have css as the first field, the casting doesn't involve any offsetting and the compiler can trivially optimize out the branch. * blkio, freezer, cpuset, cpu, cpuacct and net_cls didn't have such accessor. Added. * memory, hugetlb and devices already had one but didn't explicitly handle NULL input. Updated. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- mm/hugetlb_cgroup.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/hugetlb_cgroup.c') diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index d2f9fc0b186e..95585a0b9c8d 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -36,7 +36,7 @@ static struct hugetlb_cgroup *root_h_cgroup __read_mostly; static inline struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s) { - return container_of(s, struct hugetlb_cgroup, css); + return s ? container_of(s, struct hugetlb_cgroup, css) : NULL; } static inline -- cgit v1.2.3 From 6387698699afd72d6304566fb6ccf84bffe07c56 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Aug 2013 20:11:23 -0400 Subject: cgroup: add css_parent() Currently, controllers have to explicitly follow the cgroup hierarchy to find the parent of a given css. cgroup is moving towards using cgroup_subsys_state as the main controller interface construct, so let's provide a way to climb the hierarchy using just csses. This patch implements css_parent() which, given a css, returns its parent. The function is guarnateed to valid non-NULL parent css as long as the target css is not at the top of the hierarchy. freezer, cpuset, cpu, cpuacct, hugetlb, memory, net_cls and devices are converted to use css_parent() instead of accessing cgroup->parent directly. * __parent_ca() is dropped from cpuacct and its usage is replaced with parent_ca(). The only difference between the two was NULL test on cgroup->parent which is now embedded in css_parent() making the distinction moot. Note that eventually a css->parent field will be added to css and the NULL check in css_parent() will go away. This patch shouldn't cause any behavior differences. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- mm/hugetlb_cgroup.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'mm/hugetlb_cgroup.c') diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index 95585a0b9c8d..57ecb5d2513f 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -59,11 +59,7 @@ static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg) static inline struct hugetlb_cgroup * parent_hugetlb_cgroup(struct hugetlb_cgroup *h_cg) { - struct cgroup *parent = h_cg->css.cgroup->parent; - - if (!parent) - return NULL; - return hugetlb_cgroup_from_cgroup(parent); + return hugetlb_cgroup_from_css(css_parent(&h_cg->css)); } static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg) -- cgit v1.2.3 From eb95419b023abacb415e2a18fea899023ce7624d Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Aug 2013 20:11:23 -0400 Subject: cgroup: pass around cgroup_subsys_state instead of cgroup in subsystem methods cgroup is currently in the process of transitioning to using struct cgroup_subsys_state * as the primary handle instead of struct cgroup * in subsystem implementations for the following reasons. * With unified hierarchy, subsystems will be dynamically bound and unbound from cgroups and thus css's (cgroup_subsys_state) may be created and destroyed dynamically over the lifetime of a cgroup, which is different from the current state where all css's are allocated and destroyed together with the associated cgroup. This in turn means that cgroup_css() should be synchronized and may return NULL, making it more cumbersome to use. * Differing levels of per-subsystem granularity in the unified hierarchy means that the task and descendant iterators should behave differently depending on the specific subsystem the iteration is being performed for. * In majority of the cases, subsystems only care about its part in the cgroup hierarchy - ie. the hierarchy of css's. Subsystem methods often obtain the matching css pointer from the cgroup and don't bother with the cgroup pointer itself. Passing around css fits much better. This patch converts all cgroup_subsys methods to take @css instead of @cgroup. The conversions are mostly straight-forward. A few noteworthy changes are * ->css_alloc() now takes css of the parent cgroup rather than the pointer to the new cgroup as the css for the new cgroup doesn't exist yet. Knowing the parent css is enough for all the existing subsystems. * In kernel/cgroup.c::offline_css(), unnecessary open coded css dereference is replaced with local variable access. This patch shouldn't cause any behavior differences. v2: Unnecessary explicit cgrp->subsys[] deref in css_online() replaced with local variable @css as suggested by Li Zefan. Rebased on top of new for-3.12 which includes for-3.11-fixes so that ->css_free() invocation added by da0a12caff ("cgroup: fix a leak when percpu_ref_init() fails") is converted too. Suggested by Li Zefan. Signed-off-by: Tejun Heo Acked-by: Li Zefan Acked-by: Michal Hocko Acked-by: Vivek Goyal Acked-by: Aristeu Rozanski Acked-by: Daniel Wagner Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Johannes Weiner Cc: Balbir Singh Cc: Matt Helsley Cc: Jens Axboe Cc: Steven Rostedt --- mm/hugetlb_cgroup.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) (limited to 'mm/hugetlb_cgroup.c') diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index 57ecb5d2513f..e2132435060f 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -73,19 +73,18 @@ static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg) return false; } -static struct cgroup_subsys_state *hugetlb_cgroup_css_alloc(struct cgroup *cgroup) +static struct cgroup_subsys_state * +hugetlb_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { + struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css); + struct hugetlb_cgroup *h_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); + if (parent_h_cgroup) { for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) res_counter_init(&h_cgroup->hugepage[idx], &parent_h_cgroup->hugepage[idx]); @@ -97,11 +96,11 @@ static struct cgroup_subsys_state *hugetlb_cgroup_css_alloc(struct cgroup *cgrou return &h_cgroup->css; } -static void hugetlb_cgroup_css_free(struct cgroup *cgroup) +static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css) { struct hugetlb_cgroup *h_cgroup; - h_cgroup = hugetlb_cgroup_from_cgroup(cgroup); + h_cgroup = hugetlb_cgroup_from_css(css); kfree(h_cgroup); } @@ -150,9 +149,9 @@ out: * Force the hugetlb cgroup to empty the hugetlb resources by moving them to * the parent cgroup. */ -static void hugetlb_cgroup_css_offline(struct cgroup *cgroup) +static void hugetlb_cgroup_css_offline(struct cgroup_subsys_state *css) { - struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); + struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); struct hstate *h; struct page *page; int idx = 0; -- cgit v1.2.3 From 182446d087906de40e514573a92a97b203695f71 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Aug 2013 20:11:24 -0400 Subject: cgroup: pass around cgroup_subsys_state instead of cgroup in file methods cgroup is currently in the process of transitioning to using struct cgroup_subsys_state * as the primary handle instead of struct cgroup. Please see the previous commit which converts the subsystem methods for rationale. This patch converts all cftype file operations to take @css instead of @cgroup. cftypes for the cgroup core files don't have their subsytem pointer set. These will automatically use the dummy_css added by the previous patch and can be converted the same way. Most subsystem conversions are straight forwards but there are some interesting ones. * freezer: update_if_frozen() is also converted to take @css instead of @cgroup for consistency. This will make the code look simpler too once iterators are converted to use css. * memory/vmpressure: mem_cgroup_from_css() needs to be exported to vmpressure while mem_cgroup_from_cont() can be made static. Updated accordingly. * cpu: cgroup_tg() doesn't have any user left. Removed. * cpuacct: cgroup_ca() doesn't have any user left. Removed. * hugetlb: hugetlb_cgroup_form_cgroup() doesn't have any user left. Removed. * net_cls: cgrp_cls_state() doesn't have any user left. Removed. Signed-off-by: Tejun Heo Acked-by: Li Zefan Acked-by: Michal Hocko Acked-by: Vivek Goyal Acked-by: Aristeu Rozanski Acked-by: Daniel Wagner Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Johannes Weiner Cc: Balbir Singh Cc: Matt Helsley Cc: Jens Axboe Cc: Steven Rostedt --- mm/hugetlb_cgroup.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) (limited to 'mm/hugetlb_cgroup.c') diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index e2132435060f..bda8e44f6fde 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -39,12 +39,6 @@ struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s) return s ? container_of(s, struct hugetlb_cgroup, css) : NULL; } -static inline -struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup) -{ - return hugetlb_cgroup_from_css(cgroup_css(cgroup, hugetlb_subsys_id)); -} - static inline struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task) { @@ -248,14 +242,15 @@ void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, return; } -static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft, - struct file *file, char __user *buf, - size_t nbytes, loff_t *ppos) +static ssize_t hugetlb_cgroup_read(struct cgroup_subsys_state *css, + struct cftype *cft, struct file *file, + char __user *buf, size_t nbytes, + loff_t *ppos) { u64 val; char str[64]; int idx, name, len; - struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); + struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); idx = MEMFILE_IDX(cft->private); name = MEMFILE_ATTR(cft->private); @@ -265,12 +260,12 @@ static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft, return simple_read_from_buffer(buf, nbytes, ppos, str, len); } -static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft, - const char *buffer) +static int hugetlb_cgroup_write(struct cgroup_subsys_state *css, + struct cftype *cft, const char *buffer) { int idx, name, ret; unsigned long long val; - struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); + struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); idx = MEMFILE_IDX(cft->private); name = MEMFILE_ATTR(cft->private); @@ -295,10 +290,11 @@ static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft, return ret; } -static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event) +static int hugetlb_cgroup_reset(struct cgroup_subsys_state *css, + unsigned int event) { int idx, name, ret = 0; - struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); + struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); idx = MEMFILE_IDX(event); name = MEMFILE_ATTR(event); -- cgit v1.2.3