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author | Gavin Shan <shangw@linux.vnet.ibm.com> | 2012-08-01 01:46:06 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-08-01 03:42:49 +0200 |
commit | c1c9518331969f97ea403bac66f0fd4a85d204d5 (patch) | |
tree | 9a3122ec4600b94784e86a99aec61a1e93a27da5 /mm/cleancache.c | |
parent | mm/sparse: more checks on mem_section number (diff) | |
download | linux-c1c9518331969f97ea403bac66f0fd4a85d204d5.tar.xz linux-c1c9518331969f97ea403bac66f0fd4a85d204d5.zip |
mm/sparse: remove index_init_lock
sparse_index_init() uses the index_init_lock spinlock to protect root
mem_section assignment. The lock is not necessary anymore because the
function is called only during boot (during paging init which is executed
only from a single CPU) and from the hotplug code (by add_memory() via
arch_add_memory()) which uses mem_hotplug_mutex.
The lock was introduced by 28ae55c9 ("sparsemem extreme: hotplug
preparation") and sparse_index_init() was used only during boot at that
time.
Later when the hotplug code (and add_memory()) was introduced there was no
synchronization so it was possible to online more sections from the same
root probably (though I am not 100% sure about that). The first
synchronization has been added by 6ad696d2 ("mm: allow memory hotplug and
hibernation in the same kernel") which was later replaced by the
mem_hotplug_mutex - 20d6c96b ("mem-hotplug: introduce
{un}lock_memory_hotplug()").
Let's remove the lock as it is not needed and it makes the code more
confusing.
[mhocko@suse.cz: changelog]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/cleancache.c')
0 files changed, 0 insertions, 0 deletions