On 12/19/22 13:06, Michal Hocko wrote: > On Fri 16-12-22 11:20:12, Mike Kravetz wrote: > > zap_page_range was originally designed to unmap pages within an address > > range that could span multiple vmas. While working on [1], it was > > discovered that all callers of zap_page_range pass a range entirely within > > a single vma. In addition, the mmu notification call within zap_page > > range does not correctly handle ranges that span multiple vmas as calls > > should be vma specific. > > Could you spend a sentence or two explaining what is wrong here? Hmmmm? My assumption was that the range passed to mmu_notifier_range_init() was supposed to be within the specified vma. When looking into the notifier routines, I could not find any documentation about the usage of the vma within the mmu_notifier_range structure. It was introduced with commit bf198b2b34bf "mm/mmu_notifier: pass down vma and reasons why mmu notifier is happening". However, I do not see this being used today. Of course, I could be missing something, so adding Jérôme. > > > Instead of fixing zap_page_range, change all callers to use the new > > routine zap_vma_page_range. zap_vma_page_range is just a wrapper around > > zap_page_range_single passing in NULL zap details. The name is also > > more in line with other exported routines that operate within a vma. > > We can then remove zap_page_range. > > I would stick with zap_page_range_single rather than adding a new > wrapper but nothing really critical. I am fine with doing that as well. My only reason for the wrapper is that all callers outside mm/memory.c would pass in NULL zap details. > > > Also, change madvise_dontneed_single_vma to use this new routine. > > > > [1] https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.kravetz@xxxxxxxxxx/ > > Suggested-by: Peter Xu <peterx@xxxxxxxxxx> > > Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > > Other than that LGTM > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > > Thanks! Thanks for taking a look. -- Mike Kravetz
