kernel.git/arch/powerpc/kernel/cacheinfo.c, branch linux-2.6.32.y

powerpc: Fix missing L2 cache size in /sys/devices/system/cpu

2015-09-18T11:51:58Z

commit f7e9e358362557c3aa2c1ec47490f29fe880a09e upstream. This problem appears to have been introduced in 2.6.29 by commit 93197a36a9c1 "Rewrite sysfs processor cache info code". This caused lscpu to error out on at least e500v2 devices, eg: error: cannot open /sys/devices/system/cpu/cpu0/cache/index2/size: No such file or directory Some embedded powerpc systems use cache-size in DTS for the unified L2 cache size, not d-cache-size, so we need to allow for both DTS names. Added a new CACHE_TYPE_UNIFIED_D cache_type_info structure to handle this. Fixes: 93197a36a9c1 ("powerpc: Rewrite sysfs processor cache info code") Signed-off-by: Dave Olson Signed-off-by: Michael Ellerman [bwh: Backported to 3.2: - Adjust context - Preserve __cpuinit attribute on cache_do_one_devnode_unified()] Signed-off-by: Ben Hutchings (cherry picked from commit d6de5ca93fd6425dcdb21cc341365991c0c444cc) Signed-off-by: Willy Tarreau

powerpc/cacheinfo: Rename cache_dir per-cpu variable

2009-01-13T03:48:02Z

The per_cpu__ prefix on DECLARE_PER_CPU'd variables is going away; rename cache_dir to cache_dir_pcpu. Signed-off-by: Nathan Lynch Signed-off-by: Benjamin Herrenschmidt

powerpc: Rewrite sysfs processor cache info code

2009-01-08T05:25:10Z

The current code for providing processor cache information in sysfs has the following deficiencies: - several complex functions that are hard to understand - implicit recursion (cache_desc_release -> kobject_put -> cache_desc_release) - explicit recursion (create_cache_index_info) - use of two per-cpu arrays when one would suffice - duplication of work on systems where CPUs share cache Also, when I looked at implementing support for a shared_cpu_map attribute, it was pretty much impossible to handle hotplug without checking every single online CPU's cache_desc list and fixing things up... not that this is a hot path, but it would have introduced O(n^2)-ish behavior during boot. Addressing this involved rethinking the core data structures used, which didn't lend itself to an incremental approach. This implementation maintains a "forest" (potentially more than one tree) of cache objects which reflects the system's cache topology. Cache objects are instantiated as needed as CPUs come online. A per-cpu array is used mainly for sysfs-related bookkeeping; the objects in the array just point to the appropriate points in the forest. This maintains compatibility with the existing code and includes some enhancements: - Implement the shared_cpu_map attribute, which is essential for enabling userspace to discover the system's overall cache topology. - Use cache-block-size properties if cache-line-size is not available. I chose to place this implementation in a new file since it would have roughly doubled the size of sysfs.c, which is already kind of messy. Signed-off-by: Nathan Lynch Signed-off-by: Benjamin Herrenschmidt