Messages in this thread | | | Date | Tue, 5 Mar 2013 11:40:39 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: [PATCH 2/2] tmpfs: fix mempolicy object leaks |
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On Mon, 4 Mar 2013, Will Huck wrote: > > Could you explain me why shmem has more relationship with mempolicy? It seems > that there are many codes in shmem handle mempolicy, but other components in > mm subsystem just have little.
NUMA mempolicy is mostly handled in mm/mempolicy.c, which services the mbind, migrate_pages, set_mempolicy, get_mempolicy system calls: which govern how process memory is distributed across NUMA nodes.
mm/shmem.c is affected because it was also found useful to specify mempolicy on the shared memory objects which may back process memory: that includes SysV SHM and POSIX shared memory and tmpfs. mm/hugetlb.c contains some mempolicy handling for hugetlbfs; fs/ramfs is kept minimal, so nothing in there.
Those are the memory-based filesystems, where NUMA mempolicy is most natural. The regular filesystems could support shared mempolicy too, but that would raise more awkward design questions.
Hugh
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