On Thu 26-01-17 11:08:02, Michal Hocko wrote: > On Thu 26-01-17 10:36:49, Daniel Borkmann wrote: > > On 01/26/2017 08:43 AM, Michal Hocko wrote: > > > On Wed 25-01-17 21:16:42, Daniel Borkmann wrote: > [...] > > > > I assume that kvzalloc() is still the same from [1], right? If so, then > > > > it would unfortunately (partially) reintroduce the issue that was fixed. > > > > If you look above at flags, they're also passed to __vmalloc() to not > > > > trigger OOM in these situations I've experienced. > > > > > > Pushing __GFP_NORETRY to __vmalloc doesn't have the effect you might > > > think it would. It can still trigger the OOM killer becauset the flags > > > are no propagated all the way down to all allocations requests (e.g. > > > page tables). This is the same reason why GFP_NOFS is not supported in > > > vmalloc. > > > > Ok, good to know, is that somewhere clearly documented (like for the > > case with kmalloc())? > > I am afraid that we really suck on this front. I will add something. So I have folded the following to the patch 1. It is in line with kvmalloc and hopefully at least tell more than the current code. --- diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d89034a393f2..6c1aa2c68887 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1741,6 +1741,13 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, * Allocate enough pages to cover @size from the page level * allocator with @gfp_mask flags. Map them into contiguous * kernel virtual space, using a pagetable protection of @prot. + * + * Reclaim modifiers in @gfp_mask - __GFP_NORETRY, __GFP_REPEAT + * and __GFP_NOFAIL are not supported + * + * Any use of gfp flags outside of GFP_KERNEL should be consulted + * with mm people. + * */ static void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, pgprot_t prot, -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
