v2: https://lore.kernel.org/linux-media/20211007095129.22037-1-andriy.shevchenko...
The kernel.h is a set of something which is not related to each other and often used in non-crossed compilation units, especially when drivers need only one or two macro definitions from it.
Here is the split of container_of(). The goals are the following: - untwist the dependency hell a bit - drop kernel.h inclusion where it's only used for container_of() - speed up C preprocessing.
In v3: - split patch 2 to more patches (Greg) - exclude C changes (Herbert, Greg) - measure with kcbench, see below (Greg)
Cc: Thorsten Leemhuis regressions@leemhuis.info
People, like Greg KH and Miguel Ojeda, were asking about the latter. My methodology an testing has been provided in cover letter for v2 (see above) and here is what Greg KH insisted to have which is speedup of the kernel build.
$ kcbench -i 3 -j 64 -o $O -s $PWD --no-download -m Processor: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz [88 CPUs] Cpufreq; Memory: powersave [intel_pstate]; 128823 MiB Linux running: 5.6.0-2-amd64 [x86_64] Compiler: gcc (Debian 10.3.0-11) 10.3.0 Linux compiled: 5.15.0-rc4 Config; Environment: allmodconfig; CCACHE_DISABLE="1" Build command: make vmlinux modules Filling caches: This might take a while... Done Run 1 (-j 64): 464.07 seconds / 7.76 kernels/hour [P:6001%] Run 2 (-j 64): 464.64 seconds / 7.75 kernels/hour [P:6000%] Run 3 (-j 64): 486.41 seconds / 7.40 kernels/hour [P:5727%]
$ kcbench -i 3 -j 64 -o $O -s $PWD --no-download -m Processor: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz [88 CPUs] Cpufreq; Memory: powersave [intel_pstate]; 128823 MiB Linux running: 5.6.0-2-amd64 [x86_64] Compiler: gcc (Debian 10.3.0-11) 10.3.0 Linux compiled: 5.15.0-rc4 Config; Environment: allmodconfig; CCACHE_DISABLE="1" Build command: make vmlinux modules Filling caches: This might take a while... Done Run 1 (-j 64): 462.32 seconds / 7.79 kernels/hour [P:6009%] Run 2 (-j 64): 462.33 seconds / 7.79 kernels/hour [P:6006%] Run 3 (-j 64): 465.45 seconds / 7.73 kernels/hour [P:5999%]
Median values 464.64 before 462.33 after
Speedup: +0.5%
This supports and in align with my own approach, but shows lower numbers due to additional big take in the measurements (compilation without ccache).
Andy Shevchenko (7): kernel.h: Drop unneeded <linux/kernel.h> inclusion from other headers kernel.h: Split out container_of() and typeof_member() macros kunit: Replace kernel.h with the necessary inclusions list.h: Replace kernel.h with the necessary inclusions llist: Replace kernel.h with the necessary inclusions plist: Replace kernel.h with the necessary inclusions media: entity: Replace kernel.h with the necessary inclusions
include/kunit/test.h | 14 ++++++++++++-- include/linux/container_of.h | 37 ++++++++++++++++++++++++++++++++++++ include/linux/kernel.h | 31 +----------------------------- include/linux/kobject.h | 1 + include/linux/list.h | 6 ++++-- include/linux/llist.h | 4 +++- include/linux/plist.h | 5 ++++- include/linux/rwsem.h | 1 - include/linux/spinlock.h | 1 - include/media/media-entity.h | 3 ++- 10 files changed, 64 insertions(+), 39 deletions(-) create mode 100644 include/linux/container_of.h