On Mon, 5 Jun 2023, Liam R. Howlett wrote: > > You mean "mm: update validate_mm() to use vma iterator" here I guess. I > have it as a different commit id in my branch. > > I 'restored' some of the checking because I was able to work around not > having the mt_dump() definition with the vma iterator. I'm now > wondering how wide spread CONFIG_DEBUG_VM is used and if I should not > have added these extra checks. Most CONFIG_DEBUG_VM checks are quite cheap, mostly VM_BUG_ONs for easily checked conditions. If validate_mm() is still the kind of thing it used to be, checking through every vma on every mmap operation, please don't bring that into CONFIG_DEBUG_VM - it distorts performance too much, so always used to be under a separate CONFIG_DEBUG_VM_RB instead. Hugh
