On Fri, May 01, 2020 at 03:48:53PM -0700, Andrew Morton wrote: >On Fri, 1 May 2020 01:52:59 +0000 Wei Yang <richard.weiy...@gmail.com> wrote: > >> When the condition is true, there are two possibilities: > >I'm struggling with this one. > >> 1. count == SWAP_MAP_BAD >> 2. count == (SWAP_MAP_MAX & COUNT_CONTINUED) == SWAP_MAP_SHMEM > >I'm not sure what 2. is trying to say. For a start, (SWAP_MAP_MAX & >COUNT_CONTINUED) is zero. I guess it meant "|"?
Oops, you are right. It should be (SWAP_MAP_MAX | COUNT_CONTINUED). Sorry for the confusion. > >Also, the return value documentation says we return EINVAL for migration >entries. Where's that happening, or is the comment out of date? > Not paid attention to this. Take look into the code, I don't find a relationship between the swap count and migration. Seems we just make a migration entry but not duplicate it. If my understanding is correct. >> The first case would be filtered by the first if in __swap_duplicate(). >> >> And the second case means this swap entry is for shmem. Since we never >> do another duplication for shmem swap entry. This won't happen neither. > -- Wei Yang Help you, Help me
