| Message ID | 20181128085455.1164-1-mark.rutland@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PATCHv2] locking/atomics: build atomic headers as required | expand |
Hi Ingo,
Peter suggested you'd prefer a pull request for the atomic scripting rework, so
hopefully this is sufficient. :)
The rework means that the atomics are now rebuilt as-required. The headers are
built in parallel, along with other early build steps, so this isn't as
noticeable on a reasonably powerful machine. Once the headers are built,
they'll only be regenerated when their dependencies change, and can be cleaned
with a mrproper.
Thanks,
Mark.
The following changes since commit bdf37b4dd35d2517cadc10735cd33022da7df133:
locking/atomics: Fix out-of-tree build (2018-11-09 09:06:01 +0100)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git atomics/regenerate
for you to fetch changes up to 12eea59cbedcd46fe8b526a16a7f429c8548187d:
locking/atomics: build atomic headers as required (2018-11-27 13:25:09 +0000)
----------------------------------------------------------------
Mark Rutland (1):
locking/atomics: build atomic headers as required
Kbuild | 18 +-
Makefile | 8 +-
arch/arm64/include/asm/atomic.h | 2 +-
arch/x86/include/asm/atomic.h | 2 +-
include/asm-generic/atomic-instrumented.h | 1787 ----------------------
include/asm-generic/atomic-long.h | 1012 -------------
include/linux/atomic-fallback.h | 2294 -----------------------------
include/linux/atomic.h | 4 +-
scripts/Makefile.genheader | 26 +
scripts/atomic/check-atomics.sh | 19 -
10 files changed, 38 insertions(+), 5134 deletions(-)
delete mode 100644 include/asm-generic/atomic-instrumented.h
delete mode 100644 include/asm-generic/atomic-long.h
delete mode 100644 include/linux/atomic-fallback.h
create mode 100644 scripts/Makefile.genheader
delete mode 100755 scripts/atomic/check-atomics.sh
* Mark Rutland <mark.rutland@arm.com> wrote: > Andrew and Ingo report that the check-atomics.sh script is simply too > slow to run for every kernel build, and it's impractical to make it > faster without rewriting it in something other than shell. > > Rather than committing the generated headers, let's regenerate these > as-required, if we change the data or scripts used to generate the > atomic headers, or when building from a pristine tree. > > That ensures they're always up-to-date, allows them to be built in > parallel, and avoid redundant rebuilds, which is a 2-8s saving per > incremental build. Since the results are not committed, it's very > obvious that they should not be modified directly. If we need to > generate more headers in future, it's easy to extend Makefile.genheader > to permit this. > > I've verified that this works in the cases we previously had issues with > (out-of-tree builds and where scripts have no execute permissions), and > have tested these cases for both x86_64 and arm64. > > The diffstat looks nice, at least... > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Boqun Feng <boqun.feng@gmail.com> > Cc: Borislav Petkov <bp@suse.de> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Will Deacon <will.deacon@arm.com> > Cc: linux-kernel@vger.kernel.org > --- > Kbuild | 18 +- > Makefile | 8 +- > arch/arm64/include/asm/atomic.h | 2 +- > arch/x86/include/asm/atomic.h | 2 +- > include/asm-generic/atomic-instrumented.h | 1787 ---------------------- > include/asm-generic/atomic-long.h | 1012 ------------- > include/linux/atomic-fallback.h | 2294 ----------------------------- > include/linux/atomic.h | 4 +- > scripts/Makefile.genheader | 26 + > scripts/atomic/check-atomics.sh | 19 - > 10 files changed, 38 insertions(+), 5134 deletions(-) > delete mode 100644 include/asm-generic/atomic-instrumented.h > delete mode 100644 include/asm-generic/atomic-long.h > delete mode 100644 include/linux/atomic-fallback.h > create mode 100644 scripts/Makefile.genheader > delete mode 100755 scripts/atomic/check-atomics.sh So these 'automatically generated' headers are actual and important code, and I think it's bad practice to remove these from the git grep search space and history as well. Really, this whole notion of auto-generating the headers should be implemented correctly, instead of working around deficiencies in a short-term fashion that introduces other deficiencies. I never got any replies to my previous comments about this: <20181128083057.GA7879@gmail.com> Did I miss some mails of yours perhaps? Thanks, Ingo
On Thu, Dec 06, 2018 at 05:13:44PM +0100, Ingo Molnar wrote: > > * Mark Rutland <mark.rutland@arm.com> wrote: > > > Andrew and Ingo report that the check-atomics.sh script is simply too > > slow to run for every kernel build, and it's impractical to make it > > faster without rewriting it in something other than shell. > > > > Rather than committing the generated headers, let's regenerate these > > as-required, if we change the data or scripts used to generate the > > atomic headers, or when building from a pristine tree. > > > > That ensures they're always up-to-date, allows them to be built in > > parallel, and avoid redundant rebuilds, which is a 2-8s saving per > > incremental build. Since the results are not committed, it's very > > obvious that they should not be modified directly. If we need to > > generate more headers in future, it's easy to extend Makefile.genheader > > to permit this. > > > > I've verified that this works in the cases we previously had issues with > > (out-of-tree builds and where scripts have no execute permissions), and > > have tested these cases for both x86_64 and arm64. > > > > The diffstat looks nice, at least... > > > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Boqun Feng <boqun.feng@gmail.com> > > Cc: Borislav Petkov <bp@suse.de> > > Cc: Ingo Molnar <mingo@kernel.org> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Cc: Will Deacon <will.deacon@arm.com> > > Cc: linux-kernel@vger.kernel.org > > --- > > Kbuild | 18 +- > > Makefile | 8 +- > > arch/arm64/include/asm/atomic.h | 2 +- > > arch/x86/include/asm/atomic.h | 2 +- > > include/asm-generic/atomic-instrumented.h | 1787 ---------------------- > > include/asm-generic/atomic-long.h | 1012 ------------- > > include/linux/atomic-fallback.h | 2294 ----------------------------- > > include/linux/atomic.h | 4 +- > > scripts/Makefile.genheader | 26 + > > scripts/atomic/check-atomics.sh | 19 - > > 10 files changed, 38 insertions(+), 5134 deletions(-) > > delete mode 100644 include/asm-generic/atomic-instrumented.h > > delete mode 100644 include/asm-generic/atomic-long.h > > delete mode 100644 include/linux/atomic-fallback.h > > create mode 100644 scripts/Makefile.genheader > > delete mode 100755 scripts/atomic/check-atomics.sh > > So these 'automatically generated' headers are actual and important code, > and I think it's bad practice to remove these from the git grep search > space and history as well. Ok. Let's aim for that, then. :) > Really, this whole notion of auto-generating the headers should be > implemented correctly, instead of working around deficiencies in a > short-term fashion that introduces other deficiencies. I certainly agree. > I never got any replies to my previous comments about this: > > <20181128083057.GA7879@gmail.com> > > Did I miss some mails of yours perhaps? It appears my mailserver dropped that on the floor, as I can't find it in any of my mailboxes. :( Sorry about that; I'll try to figure out what happened there. This patch covers your suggestion of parallelizing things. On my box with -j64, that saves ~1.5s for a pristine allnoconfig build which otherwise takes ~15s. Practically, optimizing the scripts requires moving away from shell. The cost is all down to sub-shells resulting in fork+exec, but the scripts would be illegible without this. One option is to generate a checksum when the headers are generated and checked in, and check that at build time. I'll look into this tomorrow. Thanks, Mark.
Hi Ingo, On Thu, Dec 06, 2018 at 05:13:44PM +0100, Ingo Molnar wrote: > > * Mark Rutland <mark.rutland@arm.com> wrote: > > > Andrew and Ingo report that the check-atomics.sh script is simply too > > slow to run for every kernel build, and it's impractical to make it > > faster without rewriting it in something other than shell. > > > > Rather than committing the generated headers, let's regenerate these > > as-required, if we change the data or scripts used to generate the > > atomic headers, or when building from a pristine tree. > > > > That ensures they're always up-to-date, allows them to be built in > > parallel, and avoid redundant rebuilds, which is a 2-8s saving per > > incremental build. Since the results are not committed, it's very > > obvious that they should not be modified directly. If we need to > > generate more headers in future, it's easy to extend Makefile.genheader > > to permit this. > So these 'automatically generated' headers are actual and important code, > and I think it's bad practice to remove these from the git grep search > space and history as well. > > Really, this whole notion of auto-generating the headers should be > implemented correctly, instead of working around deficiencies in a > short-term fashion that introduces other deficiencies. > > I never got any replies to my previous comments about this: > > <20181128083057.GA7879@gmail.com> As I've just mentioned in another thread, I've sent out a couple of patches attempting to address this while leaving the headers checked-in: https://lkml.kernel.org/r/20181210175035.45096-1-mark.rutland@arm.com Thanks, Mark.
diff --git a/Kbuild b/Kbuild index 780048056ac5..005304205482 100644 --- a/Kbuild +++ b/Kbuild @@ -6,8 +6,7 @@ # 2) Generate timeconst.h # 3) Generate asm-offsets.h (may need bounds.h and timeconst.h) # 4) Check for missing system calls -# 5) check atomics headers are up-to-date -# 6) Generate constants.py (may need bounds.h) +# 5) Generate constants.py (may need bounds.h) ##### # 1) Generate bounds.h @@ -73,20 +72,7 @@ missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE $(call cmd,syscalls) ##### -# 5) Check atomic headers are up-to-date -# - -always += old-atomics -targets += old-atomics - -quiet_cmd_atomics = CALL $< - cmd_atomics = $(CONFIG_SHELL) $< - -old-atomics: scripts/atomic/check-atomics.sh FORCE - $(call cmd,atomics) - -##### -# 6) Generate constants for Python GDB integration +# 5) Generate constants for Python GDB integration # extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py diff --git a/Makefile b/Makefile index 6c40d547513c..fd871d2c2f54 100644 --- a/Makefile +++ b/Makefile @@ -224,7 +224,7 @@ clean-targets := %clean mrproper cleandocs no-dot-config-targets := $(clean-targets) \ cscope gtags TAGS tags help% %docs check% coccicheck \ $(version_h) headers_% archheaders archscripts \ - %asm-generic kernelversion %src-pkg + %asm-generic genheader kernelversion %src-pkg no-sync-config-targets := $(no-dot-config-targets) install %install \ kernelrelease @@ -1089,7 +1089,7 @@ endif # prepare2 creates a makefile if using a separate output directory. # From this point forward, .config has been reprocessed, so any rules # that need to depend on updated CONFIG_* values can be checked here. -prepare2: prepare3 outputmakefile asm-generic +prepare2: prepare3 outputmakefile asm-generic genheader prepare1: prepare2 $(version_h) $(autoksyms_h) include/generated/utsrelease.h $(cmd_crmodverdir) @@ -1113,6 +1113,10 @@ uapi-asm-generic: $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic \ src=uapi/asm obj=arch/$(SRCARCH)/include/generated/uapi/asm +PHONY += genheader +genheader: + $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.genheader obj=include/generated + PHONY += prepare-objtool prepare-objtool: $(objtool_target) diff --git a/arch/arm64/include/asm/atomic.h b/arch/arm64/include/asm/atomic.h index 1f4e9ee641c9..57c73cde3a51 100644 --- a/arch/arm64/include/asm/atomic.h +++ b/arch/arm64/include/asm/atomic.h @@ -166,7 +166,7 @@ #define arch_atomic64_dec_if_positive arch_atomic64_dec_if_positive -#include <asm-generic/atomic-instrumented.h> +#include <generated/atomic-instrumented.h> #endif #endif diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index ea3d95275b43..d1e3aca236e2 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -262,6 +262,6 @@ static inline int arch_atomic_fetch_xor(int i, atomic_t *v) # include <asm/atomic64_64.h> #endif -#include <asm-generic/atomic-instrumented.h> +#include <generated/atomic-instrumented.h> #endif /* _ASM_X86_ATOMIC_H */ diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h deleted file mode 100644 index b8f5b35216e1..000000000000 diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h deleted file mode 100644 index a833d385a70b..000000000000 diff --git a/include/linux/atomic-fallback.h b/include/linux/atomic-fallback.h deleted file mode 100644 index 1c02c0112fbb..000000000000 diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 4c0d009a46f0..bea7ceec44af 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -71,8 +71,8 @@ __ret; \ }) -#include <linux/atomic-fallback.h> +#include <generated/atomic-fallback.h> -#include <asm-generic/atomic-long.h> +#include <generated/atomic-long.h> #endif /* _LINUX_ATOMIC_H */ diff --git a/scripts/Makefile.genheader b/scripts/Makefile.genheader new file mode 100644 index 000000000000..03aac5628f69 --- /dev/null +++ b/scripts/Makefile.genheader @@ -0,0 +1,26 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Generate common headers under include/generated/ + +include scripts/Kbuild.include + +.PHONY: all + +targets += atomic-fallback.h +targets += atomic-instrumented.h +targets += atomic-long.h + +all: $(addprefix $(obj)/,$(targets)) + +atomic-dir := $(srctree)/scripts/atomic +atomic-tbl := $(atomic-dir)/atomics.tbl + +atomic-deps := $(atomic-tbl) $(atomic-dir)/atomic-tbl.sh \ + $(atomic-dir)/fallbacks/* + +quiet_cmd_genatomic = GENHDR $@ +cmd_genatomic = $(CONFIG_SHELL) $< $(atomic-tbl) > $@ + +$(obj)/atomic-%.h: $(atomic-dir)/gen-atomic-%.sh $(atomic-deps) + $(call if_changed,genatomic) +
Andrew and Ingo report that the check-atomics.sh script is simply too slow to run for every kernel build, and it's impractical to make it faster without rewriting it in something other than shell. Rather than committing the generated headers, let's regenerate these as-required, if we change the data or scripts used to generate the atomic headers, or when building from a pristine tree. That ensures they're always up-to-date, allows them to be built in parallel, and avoid redundant rebuilds, which is a 2-8s saving per incremental build. Since the results are not committed, it's very obvious that they should not be modified directly. If we need to generate more headers in future, it's easy to extend Makefile.genheader to permit this. I've verified that this works in the cases we previously had issues with (out-of-tree builds and where scripts have no execute permissions), and have tested these cases for both x86_64 and arm64. The diffstat looks nice, at least... Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Borislav Petkov <bp@suse.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-kernel@vger.kernel.org --- Kbuild | 18 +- Makefile | 8 +- arch/arm64/include/asm/atomic.h | 2 +- arch/x86/include/asm/atomic.h | 2 +- include/asm-generic/atomic-instrumented.h | 1787 ---------------------- include/asm-generic/atomic-long.h | 1012 ------------- include/linux/atomic-fallback.h | 2294 ----------------------------- include/linux/atomic.h | 4 +- scripts/Makefile.genheader | 26 + scripts/atomic/check-atomics.sh | 19 - 10 files changed, 38 insertions(+), 5134 deletions(-) delete mode 100644 include/asm-generic/atomic-instrumented.h delete mode 100644 include/asm-generic/atomic-long.h delete mode 100644 include/linux/atomic-fallback.h create mode 100644 scripts/Makefile.genheader delete mode 100755 scripts/atomic/check-atomics.sh Hi Ingo, Would you be happy to pick this up? Andrew and Peter seemed happy with v1 [1]. To save on ~5100 lines of preimage for the deleted files, I generated this patch with `git format-patch -D`, which git am will complain about. I've pushed this to my atomics/regenerate branch [2], based on the tip locking/core branch, in the hope you're happy to pick it from there. If you can let me know your preference I can resend this however you prefer. Thanks, Mark. Since v1 [1]: * Clarify commit message w.r.t. when headers get regenerated * Add missing dependencies to Makefile.genheader * Minor cleanups for Makefile.genheader [1] https://lkml.kernel.org/r/20181123153321.8561-1-mark.rutland@arm.com [2] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git atomics/regenerate diff --git a/scripts/atomic/check-atomics.sh b/scripts/atomic/check-atomics.sh deleted file mode 100755 index c30101cddf2d..000000000000 -- 2.11.0