On Thu, Nov 25, 2021 at 10:30:28AM +0100, Michal Hocko wrote: > [Cc Sebastian and Vlastimil] > > On Thu 25-11-21 09:58:31, Michal Hocko wrote: > > On Thu 25-11-21 09:55:26, Dave Chinner wrote: > > [...] > > > Correct __GFP_NOLOCKDEP support is also needed. See: > > > > > > https://lore.kernel.org/linux-mm/20211119225435.GZ449541@xxxxxxxxxxxxxxxxxxx/ > > > > I will have a closer look. This will require changes on both vmalloc and > > sl?b sides. > > This should hopefully make the trick > --- > From 0082d29c771d831e5d1b9bb4c0a61d39bac017f0 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@xxxxxxxx> > Date: Thu, 25 Nov 2021 10:20:16 +0100 > Subject: [PATCH] mm: make slab and vmalloc allocators __GFP_NOLOCKDEP aware > > sl?b and vmalloc allocators reduce the given gfp mask for their internal > needs. For that they use GFP_RECLAIM_MASK to preserve the reclaim > behavior and constrains. > > __GFP_NOLOCKDEP is not a part of that mask because it doesn't really > control the reclaim behavior strictly speaking. On the other hand > it tells the underlying page allocator to disable reclaim recursion > detection so arguably it should be part of the mask. > > Having __GFP_NOLOCKDEP in the mask will not alter the behavior in any > form so this change is safe pretty much by definition. It also adds > a support for this flag to SL?B and vmalloc allocators which will in > turn allow its use to kvmalloc as well. A lack of the support has been > noticed recently in http://lkml.kernel.org/r/20211119225435.GZ449541@xxxxxxxxxxxxxxxxxxx > > Reported-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > --- > mm/internal.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/internal.h b/mm/internal.h > index 3b79a5c9427a..2ceea20b5b2a 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -21,7 +21,7 @@ > #define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\ > __GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NOFAIL|\ > __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\ > - __GFP_ATOMIC) > + __GFP_ATOMIC|__GFP_NOLOCKDEP) > > /* The GFP flags allowed during early boot */ > #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS)) Looks reasonable to me. Acked-by: Dave Chinner <dchinner@xxxxxxxxxx> Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
