Re: [PATCH RFC 0/7] mm: PG_reserved cleanups and documentation
On 05.12.18 13:56, Michal Hocko wrote: > On Wed 05-12-18 13:28:44, David Hildenbrand wrote: > [...] >> Most notably, for device memory we can hopefully soon stop setting >> it PG_reserved > > I am busy as hell so I am not likely to look at specific patche this > week. But could you be more specific why we need to get rid of other > PG_reserved users before we can do so for device memory? > No worries, this has time. For device memory, nothing should really be needed. I am only collecting and docuumenting users and this is one user soon to go (eventually) :) > I am all for removing relicts because they just confuse people but I > fail to see any relation here. > It's really only "why is this patch set not bigger", nothing related to device memory actually :) -- Thanks, David / dhildenb
Re: [PATCH RFC 0/7] mm: PG_reserved cleanups and documentation
On Wed 05-12-18 13:28:44, David Hildenbrand wrote: [...] > Most notably, for device memory we can hopefully soon stop setting > it PG_reserved I am busy as hell so I am not likely to look at specific patche this week. But could you be more specific why we need to get rid of other PG_reserved users before we can do so for device memory? I am all for removing relicts because they just confuse people but I fail to see any relation here. -- Michal Hocko SUSE Labs
[PATCH RFC 0/7] mm: PG_reserved cleanups and documentation
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(-) -- 2.17.2
