# git rev-parse -q --verify 892db32b07b340b60492e8e543aedc039639eef1^{commit}
892db32b07b340b60492e8e543aedc039639eef1
already have revision, skipping fetch
# git checkout -q -f -B kisskb 892db32b07b340b60492e8e543aedc039639eef1
# git clean -qxdf
# < git log -1
# commit 892db32b07b340b60492e8e543aedc039639eef1
# Author: David Hildenbrand <david@redhat.com>
# Date:   Mon Dec 16 11:30:58 2019 +0100
# 
#     powerpc/pseries/cmm: fix managed page counts when migrating pages between zones
#     
#     Commit 63341ab03706 (virtio-balloon: fix managed page counts when migrating
#     pages between zones) fixed a long existing BUG in the virtio-balloon
#     driver when pages would get migrated between zones.  I did not try to
#     reproduce on powerpc, but looking at the code, the same should apply to
#     powerpc/cmm ever since it started using the balloon compaction
#     infrastructure (luckily just recently).
#     
#     In case we have to migrate a ballon page to a newpage of another zone, the
#     managed page count of both zones is wrong. Paired with memory offlining
#     (which will adjust the managed page count), we can trigger kernel crashes
#     and all kinds of different symptoms.
#     
#     Fix it by properly adjusting the managed page count when migrating if
#     the zone changed.
#     
#     We'll temporarily modify the totalram page count. If this ever becomes a
#     problem, we can fine tune by providing helpers that don't touch
#     the totalram pages (e.g., adjust_zone_managed_page_count()).
#     
#     Fixes: fe030c9b85e6 ("powerpc/pseries/cmm: Implement balloon compaction")
#     Signed-off-by: David Hildenbrand <david@redhat.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20191216103058.4958-1-david@redhat.com
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version
# < git log --format=%s --max-count=1 892db32b07b340b60492e8e543aedc039639eef1
# < make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_tqm8xx_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  tqm8xx_defconfig
# make -s -j 32 ARCH=powerpc O=/kisskb/build/powerpc-fixes_tqm8xx_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_tqm8xx_defconfig_powerpc-gcc5
# Build took: 0:00:45.852380