diff mbox series

[v2,2/2] PM: hibernate: add check of preallocate mem for image size pages

Message ID 20221104054119.1946073-3-tgsp002@gmail.com
State New
Headers
Series Fixes to the hibernate_preallocate_memory() |

Commit Message

TGSP Nov. 4, 2022, 5:41 a.m. UTC 
  From: xiongxin <xiongxin@kylinos.cn>

Added a check on the return value of preallocate_image_highmem(). If
memory preallocate is insufficient, S4 cannot be done;

I am playing 4K video on a machine with AMD or other graphics card and
only 8GiB memory, and the kernel is not configured with CONFIG_HIGHMEM.
When doing the S4 test, the analysis found that when the pages get from
minimum_image_size() is large enough, The preallocate_image_memory() and
preallocate_image_highmem() calls failed to obtain enough memory. Add
the judgment that memory preallocate is insufficient;

The detailed debugging data is as follows:

image_size: 3225923584, totalram_pages: 1968948 in
hibernate_reserved_size_init();

in hibernate_preallocate_memory():
code pages = minimum_image_size(saveable) = 717992, at this time(line):
count: 2030858
avail_normal: 2053753
highmem: 0
totalreserve_pages: 22895
max_size: 1013336
size: 787579
saveable: 1819905

When the code executes to:
pages = preallocate_image_memory(alloc, avail_normal), at that
time(line):
pages_highmem: 0
avail_normal: 1335761
alloc: 1017522
pages: 1017522

So enter the else branch judged by (pages < alloc), When executed to
size = preallocate_image_memory(alloc, avail_normal):
alloc = max_size - size = 225757;
size = preallocate_image_memory(alloc, avail_normal) = 168671, That is,
preallocate_image_memory() does not apply for all alloc memory pages,
because highmem is not enabled, and size_highmem will return 0 here, so
there is a memory page that has not been preallocated, so I think a
judgment needs to be added here.

But what I can't understand is that although pages are not preallocated
enough, "pages -= free_unnecessary_pages()" in the code below can also
discard some pages that have been preallocated, so I am not sure whether
it is appropriate to add a judgment here.

Cc: stable@vger.kernel.org
Signed-off-by: xiongxin <xiongxin@kylinos.cn>
Signed-off-by: huanglei <huanglei@kylinos.cn>
---
 kernel/power/snapshot.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Comments

Jiri Slaby Nov. 4, 2022, 6:25 a.m. UTC | #1 
On 04. 11. 22, 6:41, TGSP wrote:
> From: xiongxin <xiongxin@kylinos.cn>
> 
> Added a check on the return value of preallocate_image_highmem(). If
> memory preallocate is insufficient, S4 cannot be done;
> 
> I am playing 4K video on a machine with AMD or other graphics card and
> only 8GiB memory, and the kernel is not configured with CONFIG_HIGHMEM.
> When doing the S4 test, the analysis found that when the pages get from
> minimum_image_size() is large enough, The preallocate_image_memory() and
> preallocate_image_highmem() calls failed to obtain enough memory. Add
> the judgment that memory preallocate is insufficient;
> 
> The detailed debugging data is as follows:
> 
> image_size: 3225923584, totalram_pages: 1968948 in
> hibernate_reserved_size_init();
> 
> in hibernate_preallocate_memory():
> code pages = minimum_image_size(saveable) = 717992, at this time(line):
> count: 2030858
> avail_normal: 2053753
> highmem: 0
> totalreserve_pages: 22895
> max_size: 1013336
> size: 787579
> saveable: 1819905
> 
> When the code executes to:
> pages = preallocate_image_memory(alloc, avail_normal), at that
> time(line):
> pages_highmem: 0
> avail_normal: 1335761
> alloc: 1017522
> pages: 1017522
> 
> So enter the else branch judged by (pages < alloc), When executed to
> size = preallocate_image_memory(alloc, avail_normal):
> alloc = max_size - size = 225757;
> size = preallocate_image_memory(alloc, avail_normal) = 168671, That is,
> preallocate_image_memory() does not apply for all alloc memory pages,
> because highmem is not enabled, and size_highmem will return 0 here, so
> there is a memory page that has not been preallocated, so I think a
> judgment needs to be added here.
> 
> But what I can't understand is that although pages are not preallocated
> enough, "pages -= free_unnecessary_pages()" in the code below can also
> discard some pages that have been preallocated, so I am not sure whether
> it is appropriate to add a judgment here.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: xiongxin <xiongxin@kylinos.cn>
> Signed-off-by: huanglei <huanglei@kylinos.cn>
> ---
>   kernel/power/snapshot.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
> index c20ca5fb9adc..546d544cf7de 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -1854,6 +1854,8 @@ int hibernate_preallocate_memory(void)
>   		alloc = (count - pages) - size;
>   		pages += preallocate_image_highmem(alloc);
>   	} else {
> +		unsigned long size_highmem = 0;

This needs not be initialized, right?

> @@ -1863,8 +1865,13 @@ int hibernate_preallocate_memory(void)
>   		pages_highmem += size;
>   		alloc -= size;
>   		size = preallocate_image_memory(alloc, avail_normal);
> -		pages_highmem += preallocate_image_highmem(alloc - size);
> -		pages += pages_highmem + size;
> +		size_highmem = preallocate_image_highmem(alloc - size);
> +		if (size_highmem < (alloc - size)) {
> +			pr_err("Image allocation is %lu pages short, exit\n",
> +				alloc - size - pages_highmem);
> +			goto err_out;
> +		}
> +		pages += pages_highmem + size_highmem + size;
>   	}
>   
>   	/*
TGSP Nov. 4, 2022, 7:27 a.m. UTC | #2 
在 2022/11/4 14:25, Jiri Slaby 写道:
> On 04. 11. 22, 6:41, TGSP wrote:
>> From: xiongxin <xiongxin@kylinos.cn>
>>
>> Added a check on the return value of preallocate_image_highmem(). If
>> memory preallocate is insufficient, S4 cannot be done;
>>
>> I am playing 4K video on a machine with AMD or other graphics card and
>> only 8GiB memory, and the kernel is not configured with CONFIG_HIGHMEM.
>> When doing the S4 test, the analysis found that when the pages get from
>> minimum_image_size() is large enough, The preallocate_image_memory() and
>> preallocate_image_highmem() calls failed to obtain enough memory. Add
>> the judgment that memory preallocate is insufficient;
>>
>> The detailed debugging data is as follows:
>>
>> image_size: 3225923584, totalram_pages: 1968948 in
>> hibernate_reserved_size_init();
>>
>> in hibernate_preallocate_memory():
>> code pages = minimum_image_size(saveable) = 717992, at this time(line):
>> count: 2030858
>> avail_normal: 2053753
>> highmem: 0
>> totalreserve_pages: 22895
>> max_size: 1013336
>> size: 787579
>> saveable: 1819905
>>
>> When the code executes to:
>> pages = preallocate_image_memory(alloc, avail_normal), at that
>> time(line):
>> pages_highmem: 0
>> avail_normal: 1335761
>> alloc: 1017522
>> pages: 1017522
>>
>> So enter the else branch judged by (pages < alloc), When executed to
>> size = preallocate_image_memory(alloc, avail_normal):
>> alloc = max_size - size = 225757;
>> size = preallocate_image_memory(alloc, avail_normal) = 168671, That is,
>> preallocate_image_memory() does not apply for all alloc memory pages,
>> because highmem is not enabled, and size_highmem will return 0 here, so
>> there is a memory page that has not been preallocated, so I think a
>> judgment needs to be added here.
>>
>> But what I can't understand is that although pages are not preallocated
>> enough, "pages -= free_unnecessary_pages()" in the code below can also
>> discard some pages that have been preallocated, so I am not sure whether
>> it is appropriate to add a judgment here.
>>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: xiongxin <xiongxin@kylinos.cn>
>> Signed-off-by: huanglei <huanglei@kylinos.cn>
>> ---
>>   kernel/power/snapshot.c | 11 +++++++++--
>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
>> index c20ca5fb9adc..546d544cf7de 100644
>> --- a/kernel/power/snapshot.c
>> +++ b/kernel/power/snapshot.c
>> @@ -1854,6 +1854,8 @@ int hibernate_preallocate_memory(void)
>>           alloc = (count - pages) - size;
>>           pages += preallocate_image_highmem(alloc);
>>       } else {
>> +        unsigned long size_highmem = 0;
> 
> This needs not be initialized, right?

If there is no need to make judgments here, then in the (pages < alloc) 
branch, it is necessary to make judgments on (pages_highmem < alloc)? 
should be the same;

> 
>> @@ -1863,8 +1865,13 @@ int hibernate_preallocate_memory(void)
>>           pages_highmem += size;
>>           alloc -= size;
>>           size = preallocate_image_memory(alloc, avail_normal);
>> -        pages_highmem += preallocate_image_highmem(alloc - size);
>> -        pages += pages_highmem + size;
>> +        size_highmem = preallocate_image_highmem(alloc - size);
>> +        if (size_highmem < (alloc - size)) {
>> +            pr_err("Image allocation is %lu pages short, exit\n",
>> +                alloc - size - pages_highmem);
>> +            goto err_out;
>> +        }
>> +        pages += pages_highmem + size_highmem + size;
>>       }
>>       /*
>
diff mbox series

Patch

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index c20ca5fb9adc..546d544cf7de 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1854,6 +1854,8 @@  int hibernate_preallocate_memory(void)
 		alloc = (count - pages) - size;
 		pages += preallocate_image_highmem(alloc);
 	} else {
+		unsigned long size_highmem = 0;
+
 		/*
 		 * There are approximately max_size saveable pages at this point
 		 * and we want to reduce this number down to size.
@@ -1863,8 +1865,13 @@  int hibernate_preallocate_memory(void)
 		pages_highmem += size;
 		alloc -= size;
 		size = preallocate_image_memory(alloc, avail_normal);
-		pages_highmem += preallocate_image_highmem(alloc - size);
-		pages += pages_highmem + size;
+		size_highmem = preallocate_image_highmem(alloc - size);
+		if (size_highmem < (alloc - size)) {
+			pr_err("Image allocation is %lu pages short, exit\n",
+				alloc - size - pages_highmem);
+			goto err_out;
+		}
+		pages += pages_highmem + size_highmem + size;
 	}
 
 	/*