[PATCH RFC 0/7] mm: PG_reserved cleanups and documentation

David Hildenbrand
2018-12-05T12:28:44Z

I was recently going over all users of PG_reserved. Short story: it is
difficult and sometimes not really clear if setting/checking for
PG_reserved is only a relict from the past. Easy to break things.

I had way more cleanups in this series inititally,
but some architectures take PG_reserved as a way to apply a different
caching strategy (for MMIO pages). So I decided to only include the most
obvious changes (that are less likely to break something).

So let's see if the documentation update for PG_reserved I crafted
actually covers most cases or if there is plenty more.

Most notably, for device memory we can hopefully soon stop setting
it PG_reserved

I only briefly tested this on s390x.

David Hildenbrand (7):
agp: efficeon: no need to set PG_reserved on GATT tables
s390/vdso: don't clear PG_reserved
powerpc/vdso: don't clear PG_reserved
riscv/vdso: don't clear PG_reserved
m68k/mm: use __ClearPageReserved()
arm64: kexec: no need to ClearPageReserved()
mm: better document PG_reserved

arch/arm64/kernel/machine_kexec.c | 1 -
arch/m68k/mm/memory.c | 2 +-
arch/powerpc/kernel/vdso.c | 2 --
arch/riscv/kernel/vdso.c | 1 -
arch/s390/kernel/vdso.c | 2 --
drivers/char/agp/efficeon-agp.c | 2 --
include/linux/page-flags.h | 18 ++++++++++++++++--
7 files changed, 17 insertions(+), 11 deletions(-)

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2.17.2