[PATCH] __GENERIC_PER_CPU changes
Now CONFIG_DEBUG_INITDATA is in, initial percpu data [__per_cpu_start,__per_cpu_end] can be declared as a redzone, and invalid accesses after boot can be detected, at least for i386. We can let non possible cpus percpu data point to this 'redzone' instead of NULL . NULL was not a good choice because part of [0..32768] memory may be readable and invalid accesses may happen unnoticed. If CONFIG_DEBUG_INITDATA is not defined, each non possible cpu points to the initial percpu data (__per_cpu_offset[cpu] == 0), thus invalid accesses wont be detected/crash. This patch also moves __per_cpu_offset[] to read_mostly area to avoid false sharing. Signed-off-by: NEric Dumazet <dada1@cosmosbay.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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