[077/146] mm: make slab and vmalloc allocators __GFP_NOLOCKDEP aware

Commit Message

Andrew Morton Jan. 14, 2022, 10:07 p.m. UTC

From: Michal Hocko <[e-mail]>
Subject: 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/[e-mail]

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Michal Hocko <[e-mail]>
Reported-by: Sebastian Andrzej Siewior <[e-mail]>
Acked-by: Dave Chinner <[e-mail]>
Acked-by: Vlastimil Babka <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Dave Chinner <[e-mail]>
Cc: Ilya Dryomov <[e-mail]>
Cc: Jeff Layton <[e-mail]>
Cc: Neil Brown <[e-mail]>
Cc: Uladzislau Rezki (Sony) <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/internal.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

--- a/mm/internal.h~mm-make-slab-and-vmalloc-allocators-__gfp_nolockdep-aware
+++ a/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))