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Message-Id: <20171003185313.1017-6-mcgrof@kernel.org>
Date: Tue, 3 Oct 2017 11:53:13 -0700
From: "Luis R. Rodriguez" <mcgrof@...nel.org>
To: viro@...iv.linux.org.uk, bart.vanassche@....com,
ming.lei@...hat.com, tytso@....edu, darrick.wong@...cle.com,
jikos@...nel.org, rjw@...ysocki.net, pavel@....cz,
len.brown@...el.com, linux-fsdevel@...r.kernel.org
Cc: boris.ostrovsky@...cle.com, jgross@...e.com,
todd.e.brandt@...ux.intel.com, nborisov@...e.com, jack@...e.cz,
martin.petersen@...cle.com, ONeukum@...e.com,
oleksandr@...alenko.name, oleg.b.antonyan@...il.com,
linux-pm@...r.kernel.org, linux-block@...r.kernel.org,
linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org,
"Luis R. Rodriguez" <mcgrof@...nel.org>
Subject: [RFC 5/5] pm: remove kernel thread freezing
Now that all filesystems which used to rely on kthread
freezing have been converted to filesystem freeze/thawing
we can remove the kernel kthread freezer.
Signed-off-by: Luis R. Rodriguez <mcgrof@...nel.org>
---
Documentation/power/freezing-of-tasks.txt | 9 ------
drivers/xen/manage.c | 6 ----
include/linux/freezer.h | 4 ---
kernel/power/hibernate.c | 10 ++-----
kernel/power/power.h | 20 +------------
kernel/power/process.c | 47 -------------------------------
kernel/power/user.c | 9 ------
tools/power/pm-graph/analyze_suspend.py | 1 -
8 files changed, 3 insertions(+), 103 deletions(-)
diff --git a/Documentation/power/freezing-of-tasks.txt b/Documentation/power/freezing-of-tasks.txt
index af005770e767..477559f57c95 100644
--- a/Documentation/power/freezing-of-tasks.txt
+++ b/Documentation/power/freezing-of-tasks.txt
@@ -71,15 +71,6 @@ Rationale behind the functions dealing with freezing and thawing of tasks:
freeze_processes():
- freezes only userspace tasks
-freeze_kernel_threads():
- - freezes all tasks (including kernel threads) because we can't freeze
- kernel threads without freezing userspace tasks
-
-thaw_kernel_threads():
- - thaws only kernel threads; this is particularly useful if we need to do
- anything special in between thawing of kernel threads and thawing of
- userspace tasks, or if we want to postpone the thawing of userspace tasks
-
thaw_processes():
- thaws all tasks (including kernel threads) because we can't thaw userspace
tasks without thawing kernel threads
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index c425d03d37d2..8ca0e0c9a7d5 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -109,12 +109,6 @@ static void do_suspend(void)
goto out;
}
- err = freeze_kernel_threads();
- if (err) {
- pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
- goto out_thaw;
- }
-
err = dpm_suspend_start(PMSG_FREEZE);
if (err) {
pr_err("%s: dpm_suspend_start %d\n", __func__, err);
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index dd03e837ebb7..037ef3f16173 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -43,9 +43,7 @@ extern void __thaw_task(struct task_struct *t);
extern bool __refrigerator(bool check_kthr_stop);
extern int freeze_processes(void);
-extern int freeze_kernel_threads(void);
extern void thaw_processes(void);
-extern void thaw_kernel_threads(void);
/*
* DO NOT ADD ANY NEW CALLERS OF THIS FUNCTION
@@ -263,9 +261,7 @@ static inline void __thaw_task(struct task_struct *t) {}
static inline bool __refrigerator(bool check_kthr_stop) { return false; }
static inline int freeze_processes(void) { return -ENOSYS; }
-static inline int freeze_kernel_threads(void) { return -ENOSYS; }
static inline void thaw_processes(void) {}
-static inline void thaw_kernel_threads(void) {}
static inline bool try_to_freeze_nowarn(void) { return false; }
static inline bool try_to_freeze(void) { return false; }
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index a5c36e9c56a6..7c3af084b10a 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -352,10 +352,6 @@ int hibernation_snapshot(int platform_mode)
if (error)
goto Close;
- error = freeze_kernel_threads();
- if (error)
- goto Cleanup;
-
if (hibernation_test(TEST_FREEZER)) {
/*
@@ -363,13 +359,13 @@ int hibernation_snapshot(int platform_mode)
* successful freezer test.
*/
freezer_test_done = true;
- goto Thaw;
+ goto Cleanup;
}
error = dpm_prepare(PMSG_FREEZE);
if (error) {
dpm_complete(PMSG_RECOVER);
- goto Thaw;
+ goto Cleanup;
}
suspend_console();
@@ -405,8 +401,6 @@ int hibernation_snapshot(int platform_mode)
platform_end(platform_mode);
return error;
- Thaw:
- thaw_kernel_threads();
Cleanup:
swsusp_free();
goto Close;
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 1d2d761e3c25..333bde062e42 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -253,25 +253,7 @@ extern int pm_test_level;
#ifdef CONFIG_SUSPEND_FREEZER
static inline int suspend_freeze_processes(void)
{
- int error;
-
- error = freeze_processes();
- /*
- * freeze_processes() automatically thaws every task if freezing
- * fails. So we need not do anything extra upon error.
- */
- if (error)
- return error;
-
- error = freeze_kernel_threads();
- /*
- * freeze_kernel_threads() thaws only kernel threads upon freezing
- * failure. So we have to thaw the userspace tasks ourselves.
- */
- if (error)
- thaw_processes();
-
- return error;
+ return freeze_processes();
}
static inline void suspend_thaw_processes(void)
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 9d1277768312..2e223555b764 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -169,33 +169,6 @@ int freeze_processes(void)
return error;
}
-/**
- * freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
- *
- * On success, returns 0. On failure, -errno and only the kernel threads are
- * thawed, so as to give a chance to the caller to do additional cleanups
- * (if any) before thawing the userspace tasks. So, it is the responsibility
- * of the caller to thaw the userspace tasks, when the time is right.
- */
-int freeze_kernel_threads(void)
-{
- int error;
-
- pr_info("Freezing remaining freezable tasks ... ");
-
- pm_nosig_freezing = true;
- error = try_to_freeze_tasks(false);
- if (!error)
- pr_cont("done.");
-
- pr_cont("\n");
- BUG_ON(in_atomic());
-
- if (error)
- thaw_kernel_threads();
- return error;
-}
-
void thaw_processes(void)
{
struct task_struct *g, *p;
@@ -234,23 +207,3 @@ void thaw_processes(void)
pr_cont("done.\n");
trace_suspend_resume(TPS("thaw_processes"), 0, false);
}
-
-void thaw_kernel_threads(void)
-{
- struct task_struct *g, *p;
-
- pm_nosig_freezing = false;
- pr_info("Restarting kernel threads ... ");
-
- thaw_workqueues();
-
- read_lock(&tasklist_lock);
- for_each_process_thread(g, p) {
- if (p->flags & (PF_KTHREAD | PF_WQ_WORKER))
- __thaw_task(p);
- }
- read_unlock(&tasklist_lock);
-
- schedule();
- pr_cont("done.\n");
-}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 22df9f7ff672..ebb2e6a8ddc8 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -277,15 +277,6 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
swsusp_free();
memset(&data->handle, 0, sizeof(struct snapshot_handle));
data->ready = false;
- /*
- * It is necessary to thaw kernel threads here, because
- * SNAPSHOT_CREATE_IMAGE may be invoked directly after
- * SNAPSHOT_FREE. In that case, if kernel threads were not
- * thawed, the preallocation of memory carried out by
- * hibernation_snapshot() might run into problems (i.e. it
- * might fail or even deadlock).
- */
- thaw_kernel_threads();
break;
case SNAPSHOT_PREF_IMAGE_SIZE:
diff --git a/tools/power/pm-graph/analyze_suspend.py b/tools/power/pm-graph/analyze_suspend.py
index 1b60fe203741..545a5e2eafbe 100755
--- a/tools/power/pm-graph/analyze_suspend.py
+++ b/tools/power/pm-graph/analyze_suspend.py
@@ -138,7 +138,6 @@ class SystemValues:
'pm_prepare_console': dict(),
'pm_notifier_call_chain': dict(),
'freeze_processes': dict(),
- 'freeze_kernel_threads': dict(),
'pm_restrict_gfp_mask': dict(),
'acpi_suspend_begin': dict(),
'suspend_console': dict(),
--
2.14.0
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