On Thu 14-10-21 08:01:16, Shakeel Butt wrote: > On Thu, Oct 14, 2021 at 12:16 AM Michal Hocko <mhocko@xxxxxxxx> wrote: > > > > On Wed 13-10-21 12:43:38, Shakeel Butt wrote: > > [...] > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > > index 668edb16446a..b3acad4615d3 100644 > > > --- a/mm/page_alloc.c > > > +++ b/mm/page_alloc.c > > > @@ -5215,6 +5215,10 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, > > > unsigned int alloc_flags = ALLOC_WMARK_LOW; > > > int nr_populated = 0, nr_account = 0; > > > > > > + /* Bulk allocator does not support memcg accounting. */ > > > + if (unlikely(gfp & __GFP_ACCOUNT)) > > > + goto out; > > > > Did you mean goto failed here? This would break some which do not > > have any fallback. E.g. xfs_buf_alloc_pages but likely more. > > > > Sorry I could have been more specific when talking about bypassing the > > bulk allocator. It is quite confusing because the bulk allocator > > interface consists of the bulk allocator and the fallback to the normal > > page allocator. > > > > I did consider 'goto failed' here but for that I have to move > __GFP_ACCOUNT check after the "Already populated array" check in the > function. Basically what's the point of doing other operations > (incrementing nr_populated) if we are gonna skip bulk anyways. I have to say I do not follow why that is a problem. > Regarding xfs_buf_alloc_pages(), it is not using __GFP_ACCOUNT and > vmalloc() is the only __GFP_ACCOUNT user at this point. So, not an > issue for now but I suppose it is better to be future-proof and do the > 'goto failed'. Why do we want to have that silent trap? -- Michal Hocko SUSE Labs
