diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-06 21:14:42 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-06 21:14:42 -0700 |
commit | 33caee39925b887a99a2400dc5c980097c3573f9 (patch) | |
tree | 8e68ad97e1fee88c4a3f31453041f8d139f2027e /init/Kconfig | |
parent | 6456a0438b984186a0c9c8ecc9fe3d97b7ac3613 (diff) | |
parent | f84223087402c45179be5e7060c5736c17a7b271 (diff) |
Merge branch 'akpm' (patchbomb from Andrew Morton)
Merge incoming from Andrew Morton:
- Various misc things.
- arch/sh updates.
- Part of ocfs2. Review is slow.
- Slab updates.
- Most of -mm.
- printk updates.
- lib/ updates.
- checkpatch updates.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (226 commits)
checkpatch: update $declaration_macros, add uninitialized_var
checkpatch: warn on missing spaces in broken up quoted
checkpatch: fix false positives for --strict "space after cast" test
checkpatch: fix false positive MISSING_BREAK warnings with --file
checkpatch: add test for native c90 types in unusual order
checkpatch: add signed generic types
checkpatch: add short int to c variable types
checkpatch: add for_each tests to indentation and brace tests
checkpatch: fix brace style misuses of else and while
checkpatch: add --fix option for a couple OPEN_BRACE misuses
checkpatch: use the correct indentation for which()
checkpatch: add fix_insert_line and fix_delete_line helpers
checkpatch: add ability to insert and delete lines to patch/file
checkpatch: add an index variable for fixed lines
checkpatch: warn on break after goto or return with same tab indentation
checkpatch: emit a warning on file add/move/delete
checkpatch: add test for commit id formatting style in commit log
checkpatch: emit fewer kmalloc_array/kcalloc conversion warnings
checkpatch: improve "no space after cast" test
checkpatch: allow multiple const * types
...
Diffstat (limited to 'init/Kconfig')
-rw-r--r-- | init/Kconfig | 46 |
1 files changed, 42 insertions, 4 deletions
diff --git a/init/Kconfig b/init/Kconfig index 41066e49e880..a291b7ef4738 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -807,15 +807,53 @@ config LOG_BUF_SHIFT range 12 21 default 17 help - Select kernel log buffer size as a power of 2. + Select the minimal kernel log buffer size as a power of 2. + The final size is affected by LOG_CPU_MAX_BUF_SHIFT config + parameter, see below. Any higher size also might be forced + by "log_buf_len" boot parameter. + Examples: - 17 => 128 KB + 17 => 128 KB 16 => 64 KB - 15 => 32 KB - 14 => 16 KB + 15 => 32 KB + 14 => 16 KB 13 => 8 KB 12 => 4 KB +config LOG_CPU_MAX_BUF_SHIFT + int "CPU kernel log buffer size contribution (13 => 8 KB, 17 => 128KB)" + range 0 21 + default 12 if !BASE_SMALL + default 0 if BASE_SMALL + help + This option allows to increase the default ring buffer size + according to the number of CPUs. The value defines the contribution + of each CPU as a power of 2. The used space is typically only few + lines however it might be much more when problems are reported, + e.g. backtraces. + + The increased size means that a new buffer has to be allocated and + the original static one is unused. It makes sense only on systems + with more CPUs. Therefore this value is used only when the sum of + contributions is greater than the half of the default kernel ring + buffer as defined by LOG_BUF_SHIFT. The default values are set + so that more than 64 CPUs are needed to trigger the allocation. + + Also this option is ignored when "log_buf_len" kernel parameter is + used as it forces an exact (power of two) size of the ring buffer. + + The number of possible CPUs is used for this computation ignoring + hotplugging making the compuation optimal for the the worst case + scenerio while allowing a simple algorithm to be used from bootup. + + Examples shift values and their meaning: + 17 => 128 KB for each CPU + 16 => 64 KB for each CPU + 15 => 32 KB for each CPU + 14 => 16 KB for each CPU + 13 => 8 KB for each CPU + 12 => 4 KB for each CPU + # # Architectures with an unreliable sched_clock() should select this: # |