SCC: Page size support in container environments #19968
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@hangshao0 Feel free to correct anything that you feel is inaccurate. Also, feel free to change the option names. I think there should be a way to enable/disable the new behaviour for debugging purposes. |
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FYI @pshipton |
hangshao0
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Aug 7, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
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Aug 7, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
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Aug 7, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
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Actually we can do better. #19972 removes the requirement of consistent page size in SCC. The page level operations in SCC are msync and mprotec. msync is only used on z/OS, I won't worry about it. There is no need to do mprotect if the SCC is readonly. If the data is not page aligned, we cannot do mprotect anymore, and it should be turned off. |
hangshao0
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Aug 7, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Aug 7, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
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Aug 21, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
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Sep 4, 2024
The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
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to hangshao0/openj9
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Sep 5, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats 4. Add page size info into javacore Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 5, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats 4. Add page size info into javacore Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 5, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats 4. Add page size info into javacore Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 5, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS, we can always do msync if we can have valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats 4. Add page size info into javacore Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 5, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 5, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
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this issue
Sep 10, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
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this issue
Sep 11, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 11, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 11, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
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@hangshao0 For 0.48, this issue will need to be resolved by the end of this week. What's the current state of this issue? Based on this issue's impact, do we need it to be fixed in 0.48 or can it be pushed to 0.49? |
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This issue can be fixed by #19972, which is ready to be reviewed. |
hangshao0
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Sep 17, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
that referenced
this issue
Sep 17, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
hangshao0
added a commit
to hangshao0/openj9
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this issue
Sep 18, 2024
1. The page level operation in SCC are msync and mprotect. msync is only used on z/OS for persistent cache, we can always do msync if we have a valid _osPageSize. For mprotect, it is turned off if the SCC is readonly. If the data is not paged aligned anymore, mprotect should be also be turned off. There is no need to force consistent memory page size between cold and warn runs anymore. 2. Add new test flags and command line test cases. 3. Add top layer page size infomation in cache stats. 4. Add page size info into javacore. Fixes eclipse-openj9#19968 Signed-off-by: Hang Shao <[email protected]>
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Currently in container environments J9 creates a read only SCC. Each SCC records the page size of the environment that it was originally built in. On JVM startup during SCC initialization the recorded page size in the SCC is checked to see if it matches the current executing environment, if it does not then an SCC failure is emitted. In container environments if the JVM is started with
-Xshareclasses:nonfatalthen the JVM will startup without the SCC, otherwise the JVM fails to start. This issue limits the portability of container images as the page sizes much match.In some cases a change in page size can be allowed. For example if the SCC is build in an environment with a higher page size, it should be allowed to be run in an environment with a smaller page size (so long as its a multiple).
Goal:
Introduce a new options
:strictPageSizeand:nonStrictPageSizethat allows for flexibility in page sizes. In container environments:nonStrictPageSizeshould be default.The text was updated successfully, but these errors were encountered: