# git rev-parse -q --verify 3a7e02c040b130b5545e4b115aada7bacd80a2b6^{commit}
3a7e02c040b130b5545e4b115aada7bacd80a2b6
already have revision, skipping fetch
# git checkout -q -f -B kisskb 3a7e02c040b130b5545e4b115aada7bacd80a2b6
# git clean -qxdf
# < git log -1
# commit 3a7e02c040b130b5545e4b115aada7bacd80a2b6
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Fri Jul 26 15:32:27 2024 -0700
# 
#     minmax: avoid overly complicated constant expressions in VM code
#     
#     The minmax infrastructure is overkill for simple constants, and can
#     cause huge expansions because those simple constants are then used by
#     other things.
#     
#     For example, 'pageblock_order' is a core VM constant, but because it was
#     implemented using 'min_t()' and all the type-checking that involves, it
#     actually expanded to something like 2.5kB of preprocessor noise.
#     
#     And when that simple constant was then used inside other expansions:
#     
#       #define pageblock_nr_pages      (1UL << pageblock_order)
#       #define pageblock_start_pfn(pfn)  ALIGN_DOWN((pfn), pageblock_nr_pages)
#     
#     and we then use that inside a 'max()' macro:
#     
#             case ISOLATE_SUCCESS:
#                     update_cached = false;
#                     last_migrated_pfn = max(cc->zone->zone_start_pfn,
#                             pageblock_start_pfn(cc->migrate_pfn - 1));
#     
#     the end result was that one statement expanding to 253kB in size.
#     
#     There are probably other cases of this, but this one case certainly
#     stood out.
#     
#     I've added 'MIN_T()' and 'MAX_T()' macros for this kind of "core simple
#     constant with specific type" use.  These macros skip the type checking,
#     and as such need to be very sparingly used only for obvious cases that
#     have active issues like this.
#     
#     Reported-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
#     Link: https://lore.kernel.org/all/36aa2cad-1db1-4abf-8dd2-fb20484aabc3@lucifer.local/
#     Cc: David Laight <David.Laight@aculab.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/s390-linux/bin/s390-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-13.1.0-nolibc/s390-linux/bin/s390-linux-ld --version
# < git log --format=%s --max-count=1 3a7e02c040b130b5545e4b115aada7bacd80a2b6
# make -s -j 24 ARCH=s390 O=/kisskb/build/linus_allmodconfig_s390x-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/s390-linux/bin/s390-linux-  allmodconfig
# Added to kconfig CONFIG_BUILD_DOCSRC=n
# Added to kconfig CONFIG_MODULE_SIG=n
# Added to kconfig CONFIG_SAMPLES=n
# Added to kconfig CONFIG_GCC_PLUGINS=n
# Added to kconfig 
# < make -s -j 24 ARCH=s390 O=/kisskb/build/linus_allmodconfig_s390x-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/s390-linux/bin/s390-linux-  help
# make -s -j 24 ARCH=s390 O=/kisskb/build/linus_allmodconfig_s390x-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/s390-linux/bin/s390-linux-  olddefconfig
# make -s -j 24 ARCH=s390 O=/kisskb/build/linus_allmodconfig_s390x-gcc13 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-13.1.0-nolibc/s390-linux/bin/s390-linux-  
Completed OK
# rm -rf /kisskb/build/linus_allmodconfig_s390x-gcc13
# Build took: 0:54:25.660912