Fix ACE_Shared_Memory_Pool #2077
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* ACE/ace/SV_Shared_Memory.h:
* ACE/ace/MMAP_Memory_Pool.cpp:
* ACE/ace/Malloc_T.cpp:
* ACE/ace/Malloc_T.inl:
* ACE/ace/Mem_Map.cpp:
* ACE/ace/Shared_Memory.h:
* ACE/ace/Shared_Memory_MM.h:
* ACE/ace/Shared_Memory_Pool.cpp:
* ACE/ace/Shared_Memory_Pool.h:
…m shared memory segments when we don't use them anymore. At the moment the memory pool is destroyed also let the OS release all resources
* ACE/ace/Shared_Memory_Pool.cpp:
* ACE/ace/Shared_Memory_Pool.h:
* ACE/ace/Shared_Memory_Pool.cpp:
* ACE/examples/System_V_IPC/SV_Semaphores/Semaphores_2.cpp:
* ACE/tests/SV_Shared_Memory_Test.cpp:
…ith older ACE versions
* ACE/ace/Shared_Memory_Pool.cpp:
* ACE/ace/Shared_Memory_Pool.h:
mitza-oci
reviewed
Jun 19, 2023
* ACE/ace/Malloc_T.h:
* ACE/ace/Malloc_T.cpp:
* ACE/ace/Shared_Memory_Pool.cpp:
* ACE/ace/Shared_Memory_Pool.h:
* ACE/ace/Malloc_T.cpp:
* ACE/ace/Malloc_T.h:
mitza-oci
requested changes
Jun 20, 2023
Co-authored-by: Adam Mitz <mitza@objectcomputing.com>
* ACE/NEWS:
mitza-oci
approved these changes
Jun 20, 2023
mitza-oci
added a commit
to mitza-oci/ACE_TAO
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this pull request
Jun 22, 2023
Fix ACE_Shared_Memory_Pool (cherry picked from commit 7ee0839) # Conflicts: # ACE/NEWS # ACE/ace/SV_Shared_Memory.h # ACE/ace/Shared_Memory_Pool.cpp # ACE/examples/System_V_IPC/SV_Semaphores/Semaphores_2.cpp # ACE/tests/SV_Shared_Memory_Test.cpp
This was referenced Jun 23, 2023
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The ACE_Shared_Memory_Pool doesn't release the shared memory as it should on release. This leads to an increase of used shared memory on a system where part of the processes are restarted. This can be reproduced by using an OpenDDS test using shared memory where the subscriber keeps running and the publishers are each time restarted. After each restart of the publisher run
sudo pmap -p $(pidof subscriber) | grep shmidand notice that the number of shmid mappings only increases.In high level overview the following operations should be used by ACE:
shmget()allocates as much physical memory as you request for the segment.shmat()programs the MMU and sets things up in the kernel so that some address range in your process maps to the segment.shmdt()does the reverse operation and removes the mapping.shmctl()with IPC_RMID deallocates the physical memory of the segment (marks it as free).Before this PR ACE didn't use
shmdtat all, onlyshmctlwas used on release. In order to useshmdtwe need to store the addresses returned byshmatand we also need to keep the shmid of the first segment in a member variable as we can't read it from the shared memory segment itself because after callingshmdtwe can't read that memory anymore