From: xueqin Luo <[email protected]>
As computers have more and more memory, they can store larger and
larger images. This poses a problem. Let's take a 16GB computer as
an example. When the number of pre-allocated pages is greater than
900,000 and smaller than image_size, the duration of S4 increases
with the number of saved pages. When the number of pre-allocated
pages reaches 1.2 million, the duration of S4 increases by 8-10s.
We found that the image size is generally more than 900,000 pages,
so we set the default size of image_size for 16GB and above
computers to 1 million pages, which can reduce the running time
of S4 under certain conditions.
This is the test data for 5 hours after the computer is turned on:
Original kernel begin:
[2023-02-24 19:16:56] [ 46.105423][ 2] [ T3075] PM: hibernation entry
[2023-02-24 19:16:59] [ 47.632000][ 1] [ T3075] done (allocated
959239 pages)
[2023-02-24 19:18:05] [ 56.987043][ 2] [ T3075] PM: hibernation exit
Five hours later:
[2023-02-25 00:22:48] [18069.651640][ 4] [ T7590] PM: hibernation entry
[2023-02-25 01:23:59] [21671.194049][ 0] [ T8563] done (allocated
1228878 pages)
[2023-02-25 00:24:06] [18080.639889][ 2] [ T7590] PM: hibernation exit
After 5h, you can see that the S4 takes 8s more time.
Five hours later, the modified kernel test data:
[2023-02-24 15:52:08] [18190.171183][ 7] [T11151] PM: hibernation entry
[2023-02-24 15:52:11] [18191.677021][ 7] [T11151] done (allocated
792597 pages)
[2023-02-24 15:53:15] [18201.028488][ 2] [T11151] PM: hibernation exit
You can see that after five hours, the time has changed little compared
to the initial test data.
Signed-off-by: xueqin Luo <[email protected]>
---
v3: modify some comments
v2: add test data
kernel/power/snapshot.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index cd8b7b35f1e8..fa3950b19849 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -136,7 +136,14 @@ unsigned long image_size;
void __init hibernate_image_size_init(void)
{
- image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
+ /* The totalram pages() for a computer of 16 memory size is
+ * equal to 4032990 pages. And according to our observation,
+ * the average image size is less than 1 million pages.
+ */
+ if (totalram_pages() < 4032990)
+ image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
+ else
+ image_size = 1000000 * PAGE_SIZE;
}
/*
--
2.25.1
On Fri, Mar 3, 2023 at 6:51 AM Xueqin Luo <[email protected]> wrote:
>
> From: xueqin Luo <[email protected]>
>
> As computers have more and more memory, they can store larger and
> larger images. This poses a problem. Let's take a 16GB computer as
> an example. When the number of pre-allocated pages is greater than
> 900,000 and smaller than image_size, the duration of S4 increases
> with the number of saved pages. When the number of pre-allocated
> pages reaches 1.2 million, the duration of S4 increases by 8-10s.
Well, I'm not quite sure what the problem is from the description
above. Can you please explain?
> We found that the image size is generally more than 900,000 pages,
> so we set the default size of image_size for 16GB and above
> computers to 1 million pages, which can reduce the running time
> of S4 under certain conditions.
>
> This is the test data for 5 hours after the computer is turned on:
>
> Original kernel begin:
>
> [2023-02-24 19:16:56] [ 46.105423][ 2] [ T3075] PM: hibernation entry
> [2023-02-24 19:16:59] [ 47.632000][ 1] [ T3075] done (allocated
> 959239 pages)
> [2023-02-24 19:18:05] [ 56.987043][ 2] [ T3075] PM: hibernation exit
>
> Five hours later:
>
> [2023-02-25 00:22:48] [18069.651640][ 4] [ T7590] PM: hibernation entry
> [2023-02-25 01:23:59] [21671.194049][ 0] [ T8563] done (allocated
> 1228878 pages)
> [2023-02-25 00:24:06] [18080.639889][ 2] [ T7590] PM: hibernation exit
>
> After 5h, you can see that the S4 takes 8s more time.
>
> Five hours later, the modified kernel test data:
>
> [2023-02-24 15:52:08] [18190.171183][ 7] [T11151] PM: hibernation entry
> [2023-02-24 15:52:11] [18191.677021][ 7] [T11151] done (allocated
> 792597 pages)
> [2023-02-24 15:53:15] [18201.028488][ 2] [T11151] PM: hibernation exit
>
> You can see that after five hours, the time has changed little compared
> to the initial test data.
>
> Signed-off-by: xueqin Luo <[email protected]>
> ---
>
> v3: modify some comments
>
> v2: add test data
>
> kernel/power/snapshot.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index cd8b7b35f1e8..fa3950b19849 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -136,7 +136,14 @@ unsigned long image_size;
>
> void __init hibernate_image_size_init(void)
> {
> - image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
> + /* The totalram pages() for a computer of 16 memory size is
> + * equal to 4032990 pages. And according to our observation,
> + * the average image size is less than 1 million pages.
> + */
> + if (totalram_pages() < 4032990)
> + image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
> + else
> + image_size = 1000000 * PAGE_SIZE;
> }
>
> /*
> --
> 2.25.1
>