/* * * 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/page_counter.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 page_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) static struct hugetlb_cgroup *root_h_cgroup __read_mostly; static inline 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_task(struct task_struct *task) { return hugetlb_cgroup_from_css(task_css(task, hugetlb_cgrp_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 hugetlb_cgroup *h_cg) { return hugetlb_cgroup_from_css(h_cg->css.parent); } static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg) { int idx; for (idx = 0; idx < hugetlb_max_hstate; idx++) { if (page_counter_read(&h_cg->hugepage[idx])) return true; } return false; } static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup, struct hugetlb_cgroup *parent_h_cgroup) { int idx; for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) { struct page_counter *counter = &h_cgroup->hugepage[idx]; struct page_counter *parent = NULL; unsigned long limit; int ret; if (parent_h_cgroup) parent = &parent_h_cgroup->hugepage[idx]; page_counter_init(counter, parent); limit = round_down(PAGE_COUNTER_MAX, 1 << huge_page_order(&hstates[idx])); ret = page_counter_set_max(counter, limit); VM_BUG_ON(ret); } } 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; h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL); if (!h_cgroup) return ERR_PTR(-ENOMEM); if (!parent_h_cgroup) root_h_cgroup = h_cgroup; hugetlb_cgroup_init(h_cgroup, parent_h_cgroup); return &h_cgroup->css; } static void hugetlb_cgroup_css_free(struct cgroup_subsys_state *css) { struct hugetlb_cgroup *h_cgroup; h_cgroup = hugetlb_cgroup_from_css(css); 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 hugetlb_cgroup *h_cg, struct page *page) { unsigned int nr_pages; struct page_counter *counter; struct hugetlb_cgroup *page_hcg; struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg); 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; nr_pages = 1 << compound_order(page); if (!parent) { parent = root_h_cgroup; /* root has no limit */ page_counter_charge(&parent->hugepage[idx], nr_pages); } counter = &h_cg->hugepage[idx]; /* Take the pages off the local counter */ page_counter_cancel(counter, nr_pages); 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_subsys_state *css) { struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); 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, h_cg, page); spin_unlock(&hugetlb_lock); idx++; } cond_resched(); } while (hugetlb_cgroup_have_usage(h_cg)); } int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup **ptr) { int ret = 0; struct page_counter *counter; struct hugetlb_cgroup *h_cg = NULL; 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_online(&h_cg->css)) { rcu_read_unlock(); goto again; } rcu_read_unlock(); if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter)) ret = -ENOMEM; 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; if (hugetlb_cgroup_disabled()) return; lockdep_assert_held(&hugetlb_lock); h_cg = hugetlb_cgroup_from_page(page); if (unlikely(!h_cg)) return; set_hugetlb_cgroup(page, NULL); page_counter_uncharge(&h_cg->hugepage[idx], nr_pages); return; } void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages, struct hugetlb_cgroup *h_cg) { if (hugetlb_cgroup_disabled() || !h_cg) return; if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER) return; page_counter_uncharge(&h_cg->hugepage[idx], nr_pages); return; } enum { RES_USAGE, RES_LIMIT, RES_MAX_USAGE, RES_FAILCNT, }; static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) { struct page_counter *counter; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css); counter = &h_cg->hugepage[MEMFILE_IDX(cft->private)]; switch (MEMFILE_ATTR(cft->private)) { case RES_USAGE: return (u64)page_counter_read(counter) * PAGE_SIZE; case RES_LIMIT: return (u64)counter->max * PAGE_SIZE; case RES_MAX_USAGE: return (u64)counter->watermark * PAGE_SIZE; case RES_FAILCNT: return counter->failcnt; default: BUG(); } } static DEFINE_MUTEX(hugetlb_limit_mutex); static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { int ret, idx; unsigned long nr_pages; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of)); if (hugetlb_cgroup_is_root(h_cg)) /* Can't set limit on root */ return -EINVAL; buf = strstrip(buf); ret = page_counter_memparse(buf, "-1", &nr_pages); if (ret) return ret; idx = MEMFILE_IDX(of_cft(of)->private); nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx])); switch (MEMFILE_ATTR(of_cft(of)->private)) { case RES_LIMIT: mutex_lock(&hugetlb_limit_mutex); ret = page_counter_set_max(&h_cg->hugepage[idx], nr_pages); mutex_unlock(&hugetlb_limit_mutex); break; default: ret = -EINVAL; break; } return ret ?: nbytes; } static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { int ret = 0; struct page_counter *counter; struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of)); counter = &h_cg->hugepage[MEMFILE_IDX(of_cft(of)->private)]; switch (MEMFILE_ATTR(of_cft(of)->private)) { case RES_MAX_USAGE: page_counter_reset_watermark(counter); break; case RES_FAILCNT: counter->failcnt = 0; break; default: ret = -EINVAL; break; } return ret ?: nbytes; } 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_u64 = hugetlb_cgroup_read_u64; cft->write = 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_u64 = hugetlb_cgroup_read_u64; /* 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->write = hugetlb_cgroup_reset; cft->read_u64 = hugetlb_cgroup_read_u64; /* 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->write = hugetlb_cgroup_reset; cft->read_u64 = hugetlb_cgroup_read_u64; /* NULL terminate the last cft */ cft = &h->cgroup_files[4]; memset(cft, 0, sizeof(*cft)); WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys, h->cgroup_files)); } 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].private 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_PAGE(!PageHuge(oldhpage), 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_cgrp_subsys = { .css_alloc = hugetlb_cgroup_css_alloc, .css_offline = hugetlb_cgroup_css_offline, .css_free = hugetlb_cgroup_css_free, };