lib/rhashtable.c: simplify a strange allocation pattern

alloc_bucket_locks allocation pattern is quite unusual.  We are
preferring vmalloc when CONFIG_NUMA is enabled.  The rationale is that
vmalloc will respect the memory policy of the current process and so the
backing memory will get distributed over multiple nodes if the requester
is configured properly.  At least that is the intention, in reality
rhastable is shrunk and expanded from a kernel worker so no mempolicy
can be assumed.

Let's just simplify the code and use kvmalloc helper, which is a
transparent way to use kmalloc with vmalloc fallback, if the caller is
allowed to block and use the flag otherwise.

Link: http://lkml.kernel.org/r/20170306103032.2540-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index a930e436db5d8ff6b3e4959ae60761607bcd47cc..d9e7274a04cd98d14456b1bba9ad2e241eae8895 100644 (file)
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -86,16 +86,9 @@ static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl,
                size = min(size, 1U << tbl->nest);
 
        if (sizeof(spinlock_t) != 0) {
-               tbl->locks = NULL;
-#ifdef CONFIG_NUMA
-               if (size * sizeof(spinlock_t) > PAGE_SIZE &&
-                   gfp == GFP_KERNEL)
-                       tbl->locks = vmalloc(size * sizeof(spinlock_t));
-#endif
-               if (gfp != GFP_KERNEL)
-                       gfp |= __GFP_NOWARN | __GFP_NORETRY;
-
-               if (!tbl->locks)
+               if (gfpflags_allow_blocking(gfp))
+                       tbl->locks = kvmalloc(size * sizeof(spinlock_t), gfp);
+               else
                        tbl->locks = kmalloc_array(size, sizeof(spinlock_t),
                                                   gfp);
                if (!tbl->locks)