Info
As part of the fix to SERVER-10516, the code tries to find the next available free slot of virtual memory to allocate a memory mapped file. If the base address of the memory region or the allocation size returned by Virtual Query are not aligned to the memory mapped file granularity boundary, MongoDB will then try to map a file to an address not aligned with the correct granularity.
https://github.com/mongodb/mongo/commit/0205239ecb579e20b05cee3a0df394eb11ba14ce
Top User Comments
xgen-internal-githook commented on Mon, 10 Aug 2015 16:33:45 +0000:
Author:
{u'username': u'markbenvenuto', u'name': u'Mark Benvenuto', u'email': u'mark.benvenuto@mongodb.com'}
Message: SERVER-19805: MMap memory mapped file address allocation code cannot handle
addresses non-aligned to OS allocation granularity
Branch: v3.0
https://github.com/mongodb/mongo/commit/05cd4c789e8b1da3df6cf0fcc8f98f85e6ecc84d
xgen-internal-githook commented on Mon, 10 Aug 2015 16:29:27 +0000:
Author:
{u'username': u'markbenvenuto', u'name': u'Mark Benvenuto', u'email': u'mark.benvenuto@mongodb.com'}
Message: SERVER-19805: MMap memory mapped file address allocation code cannot handle
addresses non-aligned to OS allocation granularity
Branch: master
https://github.com/mongodb/mongo/commit/99a512ee7029d5ce20a8d3135a0f27364452255d
mark.benvenuto commented on Thu, 6 Aug 2015 22:32:36 +0000:
When we scan for free virtual memory, not all allocations are allocated to the right granularity. The allocations are aligned to OS page granularity (4kb), but need to be aligned to system allocation granularity (64kb).
