diff mbox

[OPW,kernel,v4] PM / Hibernate: Migrate to ktime_t

Message ID 20141029230813.GA45925@localhost
State New, archived
Headers show

Commit Message

Tina Ruchandani Oct. 29, 2014, 11:08 p.m. UTC
This patch migrates swsusp_show_speed and its callers to using ktime_t instead
of 'struct timeval' which suffers from the y2038 problem.

Changes to swsusp_show_speed:
        - use ktime_t for start and stop times
        - pass start and stop times by value
Calling functions affected:
        - load_image
        - load_image_lzo
        - save_image
        - save_image_lzo
        - hibernate_preallocate_memory
Design decisions:
        - use ktime_t to preserve same granularity of reporting as before
        - use centisecs logic as before to avoid 'div by zero' issues caused by
          using seconds and nanoseconds directly
        - use monotonic time (ktime_get()) since we only care about elapsed time.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>

--
Changes in v4:
 - Rebased patch off of 3.18-rc1
Changes in v3:
 - Use monotonic clock (ktime_get())
   instead of ktime_get_real()
 - Fix incorrect denominator in ktime_divns
Changes in v2:
 - Incorporate whitespace fixes suggested by
   Arnd Bergmann <arnd@arndb.de>
 - Use ktime_divns instead of ktime_to_ns and
   then do_div to get centisecs
 - Explain reason for changing elapsed_centisecs
   to u64.
---
 kernel/power/hibernate.c | 14 ++++++--------
 kernel/power/power.h     |  3 +--
 kernel/power/snapshot.c  |  9 +++++----
 kernel/power/swap.c      | 41 +++++++++++++++++++++--------------------
 4 files changed, 33 insertions(+), 34 deletions(-)

Comments

Arnd Bergmann Oct. 30, 2014, 10:21 a.m. UTC | #1
On Wednesday 29 October 2014 16:08:13 Tina Ruchandani wrote:
> This patch migrates swsusp_show_speed and its callers to using ktime_t instead
> of 'struct timeval' which suffers from the y2038 problem.
> 
> Changes to swsusp_show_speed:
>         - use ktime_t for start and stop times
>         - pass start and stop times by value
> Calling functions affected:
>         - load_image
>         - load_image_lzo
>         - save_image
>         - save_image_lzo
>         - hibernate_preallocate_memory
> Design decisions:
>         - use ktime_t to preserve same granularity of reporting as before
>         - use centisecs logic as before to avoid 'div by zero' issues caused by
>           using seconds and nanoseconds directly
>         - use monotonic time (ktime_get()) since we only care about elapsed time.
> 
> Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> 

Applied to my y2038 branch now. Please send this version to the
maintainers for this file. I'll drop it from my tree when they
pick it up for 3.19.

	Arnd
diff mbox

Patch

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index a9dfa79..6e6cb96 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -28,6 +28,7 @@ 
 #include <linux/syscore_ops.h>
 #include <linux/ctype.h>
 #include <linux/genhd.h>
+#include <linux/ktime.h>
 #include <trace/events/power.h>
 
 #include "power.h"
@@ -232,20 +233,17 @@  static void platform_recover(int platform_mode)
  * @nr_pages: Number of memory pages processed between @start and @stop.
  * @msg: Additional diagnostic message to print.
  */
-void swsusp_show_speed(struct timeval *start, struct timeval *stop,
-			unsigned nr_pages, char *msg)
+void swsusp_show_speed(ktime_t start, ktime_t stop,
+		      unsigned nr_pages, char *msg)
 {
+	ktime_t diff;
 	u64 elapsed_centisecs64;
 	unsigned int centisecs;
 	unsigned int k;
 	unsigned int kps;
 
-	elapsed_centisecs64 = timeval_to_ns(stop) - timeval_to_ns(start);
-	/*
-	 * If "(s64)elapsed_centisecs64 < 0", it will print long elapsed time,
-	 * it is obvious enough for what went wrong.
-	 */
-	do_div(elapsed_centisecs64, NSEC_PER_SEC / 100);
+	diff = ktime_sub(stop, start);
+	elapsed_centisecs64 = ktime_divns(diff, 10*NSEC_PER_MSEC);
 	centisecs = elapsed_centisecs64;
 	if (centisecs == 0)
 		centisecs = 1;	/* avoid div-by-zero */
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 2df883a..ce9b832 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -174,8 +174,7 @@  extern int hib_wait_on_bio_chain(struct bio **bio_chain);
 
 struct timeval;
 /* kernel/power/swsusp.c */
-extern void swsusp_show_speed(struct timeval *, struct timeval *,
-				unsigned int, char *);
+extern void swsusp_show_speed(ktime_t, ktime_t, unsigned int, char *);
 
 #ifdef CONFIG_SUSPEND
 /* kernel/power/suspend.c */
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 791a618..0c40c16 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -28,6 +28,7 @@ 
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/compiler.h>
+#include <linux/ktime.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -1576,11 +1577,11 @@  int hibernate_preallocate_memory(void)
 	struct zone *zone;
 	unsigned long saveable, size, max_size, count, highmem, pages = 0;
 	unsigned long alloc, save_highmem, pages_highmem, avail_normal;
-	struct timeval start, stop;
+	ktime_t start, stop;
 	int error;
 
 	printk(KERN_INFO "PM: Preallocating image memory... ");
-	do_gettimeofday(&start);
+	start = ktime_get();
 
 	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
 	if (error)
@@ -1709,9 +1710,9 @@  int hibernate_preallocate_memory(void)
 	free_unnecessary_pages();
 
  out:
-	do_gettimeofday(&stop);
+	stop = ktime_get();
 	printk(KERN_CONT "done (allocated %lu pages)\n", pages);
-	swsusp_show_speed(&start, &stop, pages, "Allocated");
+	swsusp_show_speed(start, stop, pages, "Allocated");
 
 	return 0;
 
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index aaa3261..2c9d6d5 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -30,6 +30,7 @@ 
 #include <linux/atomic.h>
 #include <linux/kthread.h>
 #include <linux/crc32.h>
+#include <linux/ktime.h>
 
 #include "power.h"
 
@@ -445,8 +446,8 @@  static int save_image(struct swap_map_handle *handle,
 	int nr_pages;
 	int err2;
 	struct bio *bio;
-	struct timeval start;
-	struct timeval stop;
+	ktime_t start;
+	ktime_t stop;
 
 	printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
 		nr_to_write);
@@ -455,7 +456,7 @@  static int save_image(struct swap_map_handle *handle,
 		m = 1;
 	nr_pages = 0;
 	bio = NULL;
-	do_gettimeofday(&start);
+	start = ktime_get();
 	while (1) {
 		ret = snapshot_read_next(snapshot);
 		if (ret <= 0)
@@ -469,12 +470,12 @@  static int save_image(struct swap_map_handle *handle,
 		nr_pages++;
 	}
 	err2 = hib_wait_on_bio_chain(&bio);
-	do_gettimeofday(&stop);
+	stop = ktime_get();
 	if (!ret)
 		ret = err2;
 	if (!ret)
 		printk(KERN_INFO "PM: Image saving done.\n");
-	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
+	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 	return ret;
 }
 
@@ -580,8 +581,8 @@  static int save_image_lzo(struct swap_map_handle *handle,
 	int nr_pages;
 	int err2;
 	struct bio *bio;
-	struct timeval start;
-	struct timeval stop;
+	ktime_t start;
+	ktime_t stop;
 	size_t off;
 	unsigned thr, run_threads, nr_threads;
 	unsigned char *page = NULL;
@@ -674,7 +675,7 @@  static int save_image_lzo(struct swap_map_handle *handle,
 		m = 1;
 	nr_pages = 0;
 	bio = NULL;
-	do_gettimeofday(&start);
+	start = ktime_get();
 	for (;;) {
 		for (thr = 0; thr < nr_threads; thr++) {
 			for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
@@ -759,12 +760,12 @@  static int save_image_lzo(struct swap_map_handle *handle,
 
 out_finish:
 	err2 = hib_wait_on_bio_chain(&bio);
-	do_gettimeofday(&stop);
+	stop = ktime_get();
 	if (!ret)
 		ret = err2;
 	if (!ret)
 		printk(KERN_INFO "PM: Image saving done.\n");
-	swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
+	swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 out_clean:
 	if (crc) {
 		if (crc->thr)
@@ -965,8 +966,8 @@  static int load_image(struct swap_map_handle *handle,
 {
 	unsigned int m;
 	int ret = 0;
-	struct timeval start;
-	struct timeval stop;
+	ktime_t start;
+	ktime_t stop;
 	struct bio *bio;
 	int err2;
 	unsigned nr_pages;
@@ -978,7 +979,7 @@  static int load_image(struct swap_map_handle *handle,
 		m = 1;
 	nr_pages = 0;
 	bio = NULL;
-	do_gettimeofday(&start);
+	start = ktime_get();
 	for ( ; ; ) {
 		ret = snapshot_write_next(snapshot);
 		if (ret <= 0)
@@ -996,7 +997,7 @@  static int load_image(struct swap_map_handle *handle,
 		nr_pages++;
 	}
 	err2 = hib_wait_on_bio_chain(&bio);
-	do_gettimeofday(&stop);
+	stop = ktime_get();
 	if (!ret)
 		ret = err2;
 	if (!ret) {
@@ -1005,7 +1006,7 @@  static int load_image(struct swap_map_handle *handle,
 		if (!snapshot_image_loaded(snapshot))
 			ret = -ENODATA;
 	}
-	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
+	swsusp_show_speed(start, stop, nr_to_read, "Read");
 	return ret;
 }
 
@@ -1067,8 +1068,8 @@  static int load_image_lzo(struct swap_map_handle *handle,
 	int ret = 0;
 	int eof = 0;
 	struct bio *bio;
-	struct timeval start;
-	struct timeval stop;
+	ktime_t start;
+	ktime_t stop;
 	unsigned nr_pages;
 	size_t off;
 	unsigned i, thr, run_threads, nr_threads;
@@ -1190,7 +1191,7 @@  static int load_image_lzo(struct swap_map_handle *handle,
 		m = 1;
 	nr_pages = 0;
 	bio = NULL;
-	do_gettimeofday(&start);
+	start = ktime_get();
 
 	ret = snapshot_write_next(snapshot);
 	if (ret <= 0)
@@ -1343,7 +1344,7 @@  out_finish:
 		wait_event(crc->done, atomic_read(&crc->stop));
 		atomic_set(&crc->stop, 0);
 	}
-	do_gettimeofday(&stop);
+	stop = ktime_get();
 	if (!ret) {
 		printk(KERN_INFO "PM: Image loading done.\n");
 		snapshot_write_finalize(snapshot);
@@ -1359,7 +1360,7 @@  out_finish:
 			}
 		}
 	}
-	swsusp_show_speed(&start, &stop, nr_to_read, "Read");
+	swsusp_show_speed(start, stop, nr_to_read, "Read");
 out_clean:
 	for (i = 0; i < ring_size; i++)
 		free_page((unsigned long)page[i]);