On Wed, Oct 13, 2021 at 04:45:35PM -0700, Shakeel Butt wrote: > On Wed, Oct 13, 2021 at 4:15 PM Roman Gushchin <guro@xxxxxx> wrote: > > > [...] > > > > > > > > Isn't it a bit too aggressive? > > > > > > > > How about > > > > if (WARN_ON_ONCE(gfp & __GFP_ACCOUNT)) > > > > > > We actually know that kvmalloc(__GFP_ACCOUNT) users exist and can > > > trigger bulk page allocator through vmalloc, so I don't think the > > > warning would be any helpful. > > > > > > > gfp &= ~__GFP_ACCOUNT; > > > > > > Bulk allocator is best effort, so callers have adequate fallbacks. > > > Transparently disabling accounting would be unexpected. > > > > I see... > > > > Shouldn't we then move this check to an upper level? > > > > E.g.: > > > > if (!(gfp & __GFP_ACCOUNT)) > > call_into_bulk_allocator(); > > else > > call_into_per_page_allocator(); > > > > If we add this check in the upper level (e.g. in vm_area_alloc_pages() > ) then I think we would need WARN_ON_ONCE(gfp & __GFP_ACCOUNT) in the > bulk allocator to detect future users. > > At the moment I am more inclined towards this patch's approach. Let's > say in future we find there is a __GFP_ACCOUNT allocation which can > benefit from bulk allocator and we decide to add such support in bulk > allocator then we would not need to change the bulk allocator callers > at that time just the bulk allocator. I agree with you. Let's apply the patch as-is.
