[PATCH 0/2] mm: Use pte marker for swapin errors

[Peter Xu]

rfc->v1:
- Rename SWAP_ERROR -> SWAPIN_ERROR [David, Miaohe]
- Added r-bs for Ying and Miaohe

Hi,

This series uses the pte marker to replace the swapin error swap entry,
then we save one more swap entry slot for swap devices.  A new pte marker
bit is defined.

One thing worth mentioning: we need the pte marker to be always built to
make sure it works like before, so I made an attempt in patch 1 to drop
CONFIG_PTE_MARKER and always compile pte marker in.  Since pte markers are
enabled in many distributions by default already, meanwhile the codeset is
really small I assume it's fine.  But still I'm tagging with RFC for this
initial version.

Smoke tested on anonymous mem on a fake swap failure.  Please have a look,
thanks.

Peter Xu (2):
  mm: Always compile in pte markers
  mm: Use pte markers for swap errors

 include/linux/swap.h    | 16 ++++----------
 include/linux/swapops.h | 49 +++++++++--------------------------------
 mm/Kconfig              |  7 ------
 mm/memory.c             | 13 ++++++-----
 mm/shmem.c              |  2 +-
 mm/swapfile.c           |  2 +-
 6 files changed, 23 insertions(+), 66 deletions(-)

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2.37.3