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linux/kernel/cgroup/debug.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 07:07:57 -07:00
// 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(sizeof(*css), GFP_KERNEL);
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);
rcu_read_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);
}
rcu_read_unlock();
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);
rcu_read_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);
}
rcu_read_unlock();
spin_unlock_irq(&css_set_lock);
kfree(name_buf);
return 0;
}
#define MAX_TASKS_SHOWN_PER_CSS 25
static 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,
u16 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;
cgroup: implement cgroup v2 thread support This patch implements cgroup v2 thread support. The goal of the thread mode is supporting hierarchical accounting and control at thread granularity while staying inside the resource domain model which allows coordination across different resource controllers and handling of anonymous resource consumptions. A cgroup is always created as a domain and can be made threaded by writing to the "cgroup.type" file. When a cgroup becomes threaded, it becomes a member of a threaded subtree which is anchored at the closest ancestor which isn't threaded. The threads of the processes which are in a threaded subtree can be placed anywhere without being restricted by process granularity or no-internal-process constraint. Note that the threads aren't allowed to escape to a different threaded subtree. To be used inside a threaded subtree, a controller should explicitly support threaded mode and be able to handle internal competition in the way which is appropriate for the resource. The root of a threaded subtree, the nearest ancestor which isn't threaded, is called the threaded domain and serves as the resource domain for the whole subtree. This is the last cgroup where domain controllers are operational and where all the domain-level resource consumptions in the subtree are accounted. This allows threaded controllers to operate at thread granularity when requested while staying inside the scope of system-level resource distribution. As the root cgroup is exempt from the no-internal-process constraint, it can serve as both a threaded domain and a parent to normal cgroups, so, unlike non-root cgroups, the root cgroup can have both domain and threaded children. Internally, in a threaded subtree, each css_set has its ->dom_cset pointing to a matching css_set which belongs to the threaded domain. This ensures that thread root level cgroup_subsys_state for all threaded controllers are readily accessible for domain-level operations. This patch enables threaded mode for the pids and perf_events controllers. Neither has to worry about domain-level resource consumptions and it's enough to simply set the flag. For more details on the interface and behavior of the thread mode, please refer to the section 2-2-2 in Documentation/cgroup-v2.txt added by this patch. v5: - Dropped silly no-op ->dom_cgrp init from cgroup_create(). Spotted by Waiman. - Documentation updated as suggested by Waiman. - cgroup.type content slightly reformatted. - Mark the debug controller threaded. v4: - Updated to the general idea of marking specific cgroups domain/threaded as suggested by PeterZ. v3: - Dropped "join" and always make mixed children join the parent's threaded subtree. v2: - After discussions with Waiman, support for mixed thread mode is added. This should address the issue that Peter pointed out where any nesting should be avoided for thread subtrees while coexisting with other domain cgroups. - Enabling / disabling thread mode now piggy backs on the existing control mask update mechanism. - Bug fixes and cleanup. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
2017-07-21 08:14:51 -07:00
debug_cgrp_subsys.threaded = true;
}