/* * * Copyright IBM Corporation, 2012 * Author Aneesh Kumar K.V <aneesh.kumar@linux.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 hugetlb_cgroup { struct cgroup_subsys_state css; /* * the counter to account for hugepages from hugetlb. */ struct res_counter hugepage[HUGE_MAX_HSTATE]; }; #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) #define MEMFILE_IDX(val) (((val) >> 16) & 0xffff) #define MEMFILE_ATTR(val) ((val) & 0xffff) struct cgroup_subsys hugetlb_subsys __read_mostly; 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); } 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 true; } return false; } static struct cgroup_subsys_state *hugetlb_cgroup_css_alloc(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++) 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; } static void hugetlb_cgroup_css_free(struct cgroup *cgroup) { struct hugetlb_cgroup *h_cgroup; h_cgroup = hugetlb_cgroup_from_cgroup(cgroup); kfree(h_cgroup); } /* * Should be called with hugetlb_lock held. * Since we are holding hugetlb_lock, pages cannot get moved from * active list or uncharged from the cgroup, So no need to get * page reference and test for page active here. This function * cannot fail. */ static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup, 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); page_hcg = hugetlb_cgroup_from_page(page); /* * We can have pages in active list without any cgroup * ie, hugepage with less than 3 pages. We can safely * ignore those pages. */ if (!page_hcg || page_hcg != h_cg) goto out; csize = PAGE_SIZE << compound_order(page); if (!parent) { parent = root_h_cgroup; /* root has no limit */ res_counter_charge_nofail(&parent->hugepage[idx], csize, &fail_res); } counter = &h_cg->hugepage[idx]; res_counter_uncharge_until(counter, counter->parent, csize); set_hugetlb_cgroup(page, parent); out: return; } /* * 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) { struct hstate *h; struct page *page; int idx = 0; do { for_each_hstate(h) { spin_lock(&hugetlb_lock); list_for_each_entry(page, &h->hugepage_activelist, lru) hugetlb_cgroup_move_parent(idx, cgroup, page); spin_unlock(&hugetlb_lock); idx++; } cond_resched(); } while (hugetlb_cgroup_have_usage(cgroup)); } int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup **ptr) { int ret = 0; struct res_counter *fail_res; struct hugetlb_cgroup *h_cg = NULL; unsigned long csize = nr_pages * PAGE_SIZE; if (hugetlb_cgroup_disabled()) goto done; /* * We don't charge any cgroup if the compound page have less * than 3 pages. */ if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) goto done; again: rcu_read_lock(); h_cg = hugetlb_cgroup_from_task(current); if (!css_tryget(&h_cg->css)) { rcu_read_unlock(); goto again; } rcu_read_unlock(); ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res); css_put(&h_cg->css); done: *ptr = h_cg; return ret; } /* Should be called with hugetlb_lock held */ void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages, struct hugetlb_cgroup *h_cg, struct page *page) { if (hugetlb_cgroup_disabled() || !h_cg) return; set_hugetlb_cgroup(page, h_cg); return; } /* * Should be called with hugetlb_lock held */ void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages, struct page *page) { struct hugetlb_cgroup *h_cg; unsigned long csize = nr_pages * PAGE_SIZE; if (hugetlb_cgroup_disabled()) return; VM_BUG_ON(!spin_is_locked(&hugetlb_lock)); h_cg = hugetlb_cgroup_from_page(page); if (unlikely(!h_cg)) return; set_hugetlb_cgroup(page, NULL); res_counter_uncharge(&h_cg->hugepage[idx], csize); return; } void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup *h_cg) { unsigned long csize = nr_pages * PAGE_SIZE; if (hugetlb_cgroup_disabled() || !h_cg) return; if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) return; res_counter_uncharge(&h_cg->hugepage[idx], csize); 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) { u64 val; char str[64]; int idx, name, len; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); idx = MEMFILE_IDX(cft->private); name = MEMFILE_ATTR(cft->private); val = res_counter_read_u64(&h_cg->hugepage[idx], name); len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val); return simple_read_from_buffer(buf, nbytes, ppos, str, len); } static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft, const char *buffer) { int idx, name, ret; unsigned long long val; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); idx = MEMFILE_IDX(cft->private); name = MEMFILE_ATTR(cft->private); switch (name) { case RES_LIMIT: if (hugetlb_cgroup_is_root(h_cg)) { /* Can't set limit on root */ ret = -EINVAL; break; } /* This function does all necessary parse...reuse it */ ret = res_counter_memparse_write_strategy(buffer, &val); if (ret) break; ret = res_counter_set_limit(&h_cg->hugepage[idx], val); break; default: ret = -EINVAL; break; } return ret; } static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event) { int idx, name, ret = 0; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup); idx = MEMFILE_IDX(event); name = MEMFILE_ATTR(event); switch (name) { case RES_MAX_USAGE: res_counter_reset_max(&h_cg->hugepage[idx]); break; case RES_FAILCNT: res_counter_reset_failcnt(&h_cg->hugepage[idx]); break; default: ret = -EINVAL; break; } return ret; } static char *mem_fmt(char *buf, int size, unsigned long hsize) { if (hsize >= (1UL << 30)) snprintf(buf, size, "%luGB", hsize >> 30); else if (hsize >= (1UL << 20)) snprintf(buf, size, "%luMB", hsize >> 20); else snprintf(buf, size, "%luKB", hsize >> 10); return buf; } static void __init __hugetlb_cgroup_file_init(int idx) { char buf[32]; struct cftype *cft; struct hstate *h = &hstates[idx]; /* format the size */ mem_fmt(buf, 32, huge_page_size(h)); /* Add the limit file */ cft = &h->cgroup_files[0]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf); cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT); cft->read = hugetlb_cgroup_read; cft->write_string = hugetlb_cgroup_write; /* Add the usage file */ cft = &h->cgroup_files[1]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf); cft->private = MEMFILE_PRIVATE(idx, RES_USAGE); cft->read = hugetlb_cgroup_read; /* Add the MAX usage file */ cft = &h->cgroup_files[2]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf); cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE); cft->trigger = hugetlb_cgroup_reset; cft->read = hugetlb_cgroup_read; /* Add the failcntfile */ cft = &h->cgroup_files[3]; snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf); cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT); cft->trigger = hugetlb_cgroup_reset; cft->read = hugetlb_cgroup_read; /* NULL terminate the last cft */ cft = &h->cgroup_files[4]; memset(cft, 0, sizeof(*cft)); WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files)); return; } void __init hugetlb_cgroup_file_init(void) { struct hstate *h; for_each_hstate(h) { /* * Add cgroup control files only if the huge page consists * of more than two normal pages. This is because we use * page[2].lru.next for storing cgroup details. */ if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER) __hugetlb_cgroup_file_init(hstate_index(h)); } } /* * hugetlb_lock will make sure a parallel cgroup rmdir won't happen * when we migrate hugepages */ void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage) { struct hugetlb_cgroup *h_cg; struct hstate *h = page_hstate(oldhpage); if (hugetlb_cgroup_disabled()) return; VM_BUG_ON(!PageHuge(oldhpage)); spin_lock(&hugetlb_lock); h_cg = hugetlb_cgroup_from_page(oldhpage); set_hugetlb_cgroup(oldhpage, NULL); /* move the h_cg details to new cgroup */ set_hugetlb_cgroup(newhpage, h_cg); list_move(&newhpage->lru, &h->hugepage_activelist); spin_unlock(&hugetlb_lock); return; } struct cgroup_subsys hugetlb_subsys = { .name = "hugetlb", .css_alloc = hugetlb_cgroup_css_alloc, .css_offline = hugetlb_cgroup_css_offline, .css_free = hugetlb_cgroup_css_free, .subsys_id = hugetlb_subsys_id, };