Messages in this thread Patch in this message | | | From | Muchun Song <> | Date | Sat, 19 Mar 2022 11:56:18 +0800 | Subject | Re: [PATCH v4 1/4] mm: hugetlb_vmemmap: introduce STRUCT_PAGE_SIZE_IS_POWER_OF_2 |
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On Sat, Mar 19, 2022 at 12:40 AM Luis Chamberlain <mcgrof@kernel.org> wrote: > > On Fri, Mar 18, 2022 at 06:07:17PM +0800, Muchun Song wrote: > > You can add Suggested-by tag here.
Will do. Sorry for forgetting it.
> > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > > --- > > Kbuild | 12 ++++++++++++ > > fs/Kconfig | 2 +- > > include/linux/mm_types.h | 2 ++ > > mm/Kconfig | 3 +++ > > mm/hugetlb_vmemmap.c | 6 ------ > > mm/struct_page_size.c | 19 +++++++++++++++++++ > > scripts/check_struct_page_po2.sh | 11 +++++++++++ > > 7 files changed, 48 insertions(+), 7 deletions(-) > > create mode 100644 mm/struct_page_size.c > > create mode 100755 scripts/check_struct_page_po2.sh > > > > diff --git a/Kbuild b/Kbuild > > index fa441b98c9f6..6bb97d348d62 100644 > > --- a/Kbuild > > +++ b/Kbuild > > @@ -14,6 +14,18 @@ $(bounds-file): kernel/bounds.s FORCE > > $(call filechk,offsets,__LINUX_BOUNDS_H__) > > > > ##### > > +# Generate struct_page_size.h. Must follows bounds.h. > > + > > +struct_page_size-file := include/generated/struct_page_size.h > > + > > +always-y := $(struct_page_size-file) > > +targets := mm/struct_page_size.s > > + > > +$(struct_page_size-file): mm/struct_page_size.s FORCE > > + $(call filechk,offsets,__LINUX_STRUCT_PAGE_SIZE_H__) > > + $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig > > + > > +##### > > Shouldn't this go into mm/Makefile instead? >
We should guarantee that the include/generated/struct_page_size.h which Kconfig depends on is created before processing Makefile since processing Kconfig is before Makefile. Right?
> > diff --git a/mm/Kconfig b/mm/Kconfig > > index 034d87953600..9314bd34f49e 100644 > > --- a/mm/Kconfig > > +++ b/mm/Kconfig > > @@ -2,6 +2,9 @@ > > > > menu "Memory Management options" > > > > +config STRUCT_PAGE_SIZE_IS_POWER_OF_2 > > + def_bool $(success,test "$(shell, $(srctree)/scripts/check_struct_page_po2.sh)" = 1) > > + > > config SELECT_MEMORY_MODEL > > def_bool y > > depends on ARCH_SELECT_MEMORY_MODEL > > new file mode 100755 > > index 000000000000..9547ad3aca05 > > --- /dev/null > > +++ b/scripts/check_struct_page_po2.sh > > @@ -0,0 +1,11 @@ > > +#!/bin/sh > > +# SPDX-License-Identifier: GPL-2.0 > > +# > > +# Check if the size of "struct page" is power of 2 > > + > > +file="include/generated/struct_page_size.h" > > +if [ ! -f "$file" ]; then > > Does this really work if one is workig off of a very clean build > like make mrproper and then make menuconfig or or mrproper followed > by a defconfig file ? Have you tried it for both cases po2 and npo2? > > Because isn't include/generated/struct_page_size.h generated? At > which point does it get generated and why would the condition hole > true that the file exists at a new 'make menuconfig' time? >
You are right. include/generated/struct_page_size.h does not exist in this case, CONFIG_STRUCT_PAGE_SIZE_IS_POWER_OF_2 will be default off in .config. Then it will be switched on/off accordingly when you build the kernel, for instance make bzImage, which is done via "make syncconfig" which follows the generation of struct_page_size.h.
While testing this case, I found some bugs. The following patch could fix this. Thanks.
--- a/Kbuild +++ b/Kbuild @@ -21,6 +21,8 @@ struct_page_size-file := include/generated/struct_page_size.h always-y := $(struct_page_size-file) targets := mm/struct_page_size.s
+mm/struct_page_size.s: $(timeconst-file) $(bounds-file) + $(struct_page_size-file): mm/struct_page_size.s FORCE $(call filechk,offsets,__LINUX_STRUCT_PAGE_SIZE_H__) $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig diff --git a/scripts/check_struct_page_po2.sh b/scripts/check_struct_page_po2.sh index 9547ad3aca05..1764ef9a4f1d 100755 --- a/scripts/check_struct_page_po2.sh +++ b/scripts/check_struct_page_po2.sh @@ -4,8 +4,6 @@ # Check if the size of "struct page" is power of 2
file="include/generated/struct_page_size.h" -if [ ! -f "$file" ]; then - exit 1 +if [ -f "$file" ]; then + grep STRUCT_PAGE_SIZE_IS_POWER_OF_2 "$file" | cut -d' ' -f3 fi - -grep STRUCT_PAGE_SIZE_IS_POWER_OF_2 "$file" | cut -d' ' -f3
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