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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378// SPDX-License-Identifier: GPL-2.0/* * Debug controller * * WARNING: This controller is for cgroup core debugging only. * Its interfaces are unstable and subject to changes at any time. */#include <linux/ctype.h>#include <linux/mm.h>#include <linux/slab.h>
#include "cgroup-internal.h"
static struct cgroup_subsys_state *debug_css_alloc(struct cgroup_subsys_state *parent_css){ struct cgroup_subsys_state *css = kzalloc_obj(*css);
if (!css) return ERR_PTR(-ENOMEM);
return css;}
static void debug_css_free(struct cgroup_subsys_state *css){ kfree(css);}
/* * debug_taskcount_read - return the number of tasks in a cgroup. * @cgrp: the cgroup in question */static u64 debug_taskcount_read(struct cgroup_subsys_state *css, struct cftype *cft){ return cgroup_task_count(css->cgroup);}
static int current_css_set_read(struct seq_file *seq, void *v){ struct kernfs_open_file *of = seq->private; struct css_set *cset; struct cgroup_subsys *ss; struct cgroup_subsys_state *css; int i, refcnt;
if (!cgroup_kn_lock_live(of->kn, false)) return -ENODEV;
spin_lock_irq(&css_set_lock); cset = task_css_set(current); refcnt = refcount_read(&cset->refcount); seq_printf(seq, "css_set %pK %d", cset, refcnt); if (refcnt > cset->nr_tasks) seq_printf(seq, " +%d", refcnt - cset->nr_tasks); seq_puts(seq, "\n");
/* * Print the css'es stored in the current css_set. */ for_each_subsys(ss, i) { css = cset->subsys[ss->id]; if (!css) continue; seq_printf(seq, "%2d: %-4s\t- %p[%d]\n", ss->id, ss->name, css, css->id); } spin_unlock_irq(&css_set_lock); cgroup_kn_unlock(of->kn); return 0;}
static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css, struct cftype *cft){ u64 count;
rcu_read_lock(); count = refcount_read(&task_css_set(current)->refcount); rcu_read_unlock(); return count;}
static int current_css_set_cg_links_read(struct seq_file *seq, void *v){ struct cgrp_cset_link *link; struct css_set *cset; char *name_buf;
name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL); if (!name_buf) return -ENOMEM;
spin_lock_irq(&css_set_lock); cset = task_css_set(current); list_for_each_entry(link, &cset->cgrp_links, cgrp_link) { struct cgroup *c = link->cgrp;
cgroup_name(c, name_buf, NAME_MAX + 1); seq_printf(seq, "Root %d group %s\n", c->root->hierarchy_id, name_buf); } spin_unlock_irq(&css_set_lock); kfree(name_buf); return 0;}
#define MAX_TASKS_SHOWN_PER_CSS 25static int cgroup_css_links_read(struct seq_file *seq, void *v){ struct cgroup_subsys_state *css = seq_css(seq); struct cgrp_cset_link *link; int dead_cnt = 0, extra_refs = 0, threaded_csets = 0;
spin_lock_irq(&css_set_lock);
list_for_each_entry(link, &css->cgroup->cset_links, cset_link) { struct css_set *cset = link->cset; struct task_struct *task; int count = 0; int refcnt = refcount_read(&cset->refcount);
/* * Print out the proc_cset and threaded_cset relationship * and highlight difference between refcount and task_count. */ seq_printf(seq, "css_set %pK", cset); if (rcu_dereference_protected(cset->dom_cset, 1) != cset) { threaded_csets++; seq_printf(seq, "=>%pK", cset->dom_cset); } if (!list_empty(&cset->threaded_csets)) { struct css_set *tcset; int idx = 0;
list_for_each_entry(tcset, &cset->threaded_csets, threaded_csets_node) { seq_puts(seq, idx ? "," : "<="); seq_printf(seq, "%pK", tcset); idx++; } } else { seq_printf(seq, " %d", refcnt); if (refcnt - cset->nr_tasks > 0) { int extra = refcnt - cset->nr_tasks;
seq_printf(seq, " +%d", extra); /* * Take out the one additional reference in * init_css_set. */ if (cset == &init_css_set) extra--; extra_refs += extra; } } seq_puts(seq, "\n");
list_for_each_entry(task, &cset->tasks, cg_list) { if (count++ <= MAX_TASKS_SHOWN_PER_CSS) seq_printf(seq, " task %d\n", task_pid_vnr(task)); }
list_for_each_entry(task, &cset->mg_tasks, cg_list) { if (count++ <= MAX_TASKS_SHOWN_PER_CSS) seq_printf(seq, " task %d\n", task_pid_vnr(task)); } /* show # of overflowed tasks */ if (count > MAX_TASKS_SHOWN_PER_CSS) seq_printf(seq, " ... (%d)\n", count - MAX_TASKS_SHOWN_PER_CSS);
if (cset->dead) { seq_puts(seq, " [dead]\n"); dead_cnt++; }
WARN_ON(count != cset->nr_tasks); } spin_unlock_irq(&css_set_lock);
if (!dead_cnt && !extra_refs && !threaded_csets) return 0;
seq_puts(seq, "\n"); if (threaded_csets) seq_printf(seq, "threaded css_sets = %d\n", threaded_csets); if (extra_refs) seq_printf(seq, "extra references = %d\n", extra_refs); if (dead_cnt) seq_printf(seq, "dead css_sets = %d\n", dead_cnt);
return 0;}
static int cgroup_subsys_states_read(struct seq_file *seq, void *v){ struct kernfs_open_file *of = seq->private; struct cgroup *cgrp; struct cgroup_subsys *ss; struct cgroup_subsys_state *css; char pbuf[16]; int i;
cgrp = cgroup_kn_lock_live(of->kn, false); if (!cgrp) return -ENODEV;
for_each_subsys(ss, i) { css = rcu_dereference_check(cgrp->subsys[ss->id], true); if (!css) continue;
pbuf[0] = '\0';
/* Show the parent CSS if applicable*/ if (css->parent) snprintf(pbuf, sizeof(pbuf) - 1, " P=%d", css->parent->id); seq_printf(seq, "%2d: %-4s\t- %p[%d] %d%s\n", ss->id, ss->name, css, css->id, atomic_read(&css->online_cnt), pbuf); }
cgroup_kn_unlock(of->kn); return 0;}
static void cgroup_masks_read_one(struct seq_file *seq, const char *name, u32 mask){ struct cgroup_subsys *ss; int ssid; bool first = true;
seq_printf(seq, "%-17s: ", name); for_each_subsys(ss, ssid) { if (!(mask & (1 << ssid))) continue; if (!first) seq_puts(seq, ", "); seq_puts(seq, ss->name); first = false; } seq_putc(seq, '\n');}
static int cgroup_masks_read(struct seq_file *seq, void *v){ struct kernfs_open_file *of = seq->private; struct cgroup *cgrp;
cgrp = cgroup_kn_lock_live(of->kn, false); if (!cgrp) return -ENODEV;
cgroup_masks_read_one(seq, "subtree_control", cgrp->subtree_control); cgroup_masks_read_one(seq, "subtree_ss_mask", cgrp->subtree_ss_mask);
cgroup_kn_unlock(of->kn); return 0;}
static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft){ return (!cgroup_is_populated(css->cgroup) && !css_has_online_children(&css->cgroup->self));}
static struct cftype debug_legacy_files[] = { { .name = "taskcount", .read_u64 = debug_taskcount_read, },
{ .name = "current_css_set", .seq_show = current_css_set_read, .flags = CFTYPE_ONLY_ON_ROOT, },
{ .name = "current_css_set_refcount", .read_u64 = current_css_set_refcount_read, .flags = CFTYPE_ONLY_ON_ROOT, },
{ .name = "current_css_set_cg_links", .seq_show = current_css_set_cg_links_read, .flags = CFTYPE_ONLY_ON_ROOT, },
{ .name = "cgroup_css_links", .seq_show = cgroup_css_links_read, },
{ .name = "cgroup_subsys_states", .seq_show = cgroup_subsys_states_read, },
{ .name = "cgroup_masks", .seq_show = cgroup_masks_read, },
{ .name = "releasable", .read_u64 = releasable_read, },
{ } /* terminate */};
static struct cftype debug_files[] = { { .name = "taskcount", .read_u64 = debug_taskcount_read, },
{ .name = "current_css_set", .seq_show = current_css_set_read, .flags = CFTYPE_ONLY_ON_ROOT, },
{ .name = "current_css_set_refcount", .read_u64 = current_css_set_refcount_read, .flags = CFTYPE_ONLY_ON_ROOT, },
{ .name = "current_css_set_cg_links", .seq_show = current_css_set_cg_links_read, .flags = CFTYPE_ONLY_ON_ROOT, },
{ .name = "css_links", .seq_show = cgroup_css_links_read, },
{ .name = "csses", .seq_show = cgroup_subsys_states_read, },
{ .name = "masks", .seq_show = cgroup_masks_read, },
{ } /* terminate */};
struct cgroup_subsys debug_cgrp_subsys = { .css_alloc = debug_css_alloc, .css_free = debug_css_free, .legacy_cftypes = debug_legacy_files,};
/* * On v2, debug is an implicit controller enabled by "cgroup_debug" boot * parameter. */void __init enable_debug_cgroup(void){ debug_cgrp_subsys.dfl_cftypes = debug_files; debug_cgrp_subsys.implicit_on_dfl = true; debug_cgrp_subsys.threaded = true;}