On Thu, Mar 03, 2022 at 01:35:56PM -0800, Nadav Amit wrote: > > > > On Mar 3, 2022, at 1:29 PM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > > > MADV_DONTNEED historically rejects mlocked ranges, but with > > MLOCK_ONFAULT and MCL_ONFAULT allowing to mlock without populating, > > there are valid use cases for depopulating locked ranges as well. > > ... > > > @@ -850,7 +858,7 @@ static long madvise_dontneed_free(struct vm_area_struct *vma, > > VM_WARN_ON(start >= end); > > } > > > > - if (behavior == MADV_DONTNEED) > > + if (behavior == MADV_DONTNEED || behavior == MADV_DONTNEED_LOCKED) > > return madvise_dontneed_single_vma(vma, start, end); > > else if (behavior == MADV_FREE) > > return madvise_free_single_vma(vma, start, end); > > @@ -988,6 +996,7 @@ static int madvise_vma_behavior(struct vm_area_struct *vma, > > return madvise_pageout(vma, prev, start, end); > > case MADV_FREE: > > case MADV_DONTNEED: > > + case MADV_DONTNEED_LOCKED: > > return madvise_dontneed_free(vma, prev, start, end, behavior); > > case MADV_POPULATE_READ: > > case MADV_POPULATE_WRITE: > > @@ -1113,6 +1122,7 @@ madvise_behavior_valid(int behavior) > > case MADV_REMOVE: > > case MADV_WILLNEED: > > case MADV_DONTNEED: > > + case MADV_DONTNEED_LOCKED: > > case MADV_FREE: > > case MADV_COLD: > > case MADV_PAGEOUT: > > Don’t you want to change madvise_need_mmap_write() as well and add > MADV_DONTNEED_LOCKED there too? You're absolutely right, thanks Nadav! It'd be fine, but more expensive than necessary. Here is the fixlet: diff --git a/mm/madvise.c b/mm/madvise.c index 12dfa14bc985..7dbfcd6c955a 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -52,6 +52,7 @@ static int madvise_need_mmap_write(int behavior) case MADV_REMOVE: case MADV_WILLNEED: case MADV_DONTNEED: + case MADV_DONTNEED_LOCKED: case MADV_COLD: case MADV_PAGEOUT: case MADV_FREE:
