| Message ID | 20221030214151.402274-1-peterx@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm: Use pte marker for swapin errors | expand |
Peter Xu <peterx@redhat.com> writes: > 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. Per my understanding, "swap entry" describes one swap page (4KB on x86) in one swap device. So, the original swapin error implementation uses one swap file (or swap device) instead of one swap entry. So your patch saves one swap file (or swap device). Best Regards, Huang, Ying > 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(-)
On Mon, Oct 31, 2022 at 09:40:15AM +0800, Huang, Ying wrote: > Peter Xu <peterx@redhat.com> writes: > > > 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. > > Per my understanding, "swap entry" describes one swap page (4KB on x86) > in one swap device. So, the original swapin error implementation uses > one swap file (or swap device) instead of one swap entry. So your patch > saves one swap file (or swap device). Yeah I was definitely not accurate enough, I wanted to use "slot" to mean "type" here but obviously I didn't make it, sorry. Hopefully the whole patchset is still clear enough anyway so no reader will get confused by it.
Peter Xu <peterx@redhat.com> writes: > On Mon, Oct 31, 2022 at 09:40:15AM +0800, Huang, Ying wrote: >> Peter Xu <peterx@redhat.com> writes: >> >> > 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. >> >> Per my understanding, "swap entry" describes one swap page (4KB on x86) >> in one swap device. So, the original swapin error implementation uses >> one swap file (or swap device) instead of one swap entry. So your patch >> saves one swap file (or swap device). > > Yeah I was definitely not accurate enough, I wanted to use "slot" to mean > "type" here but obviously I didn't make it, sorry. Hopefully the whole > patchset is still clear enough anyway so no reader will get confused by it. The terminology used in swap code is a little complex. The swap slot is used to describe swap entry (swap page) too in swap slots cache (swap_slots.c/h). Best Regards, Huang, Ying