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Message-ID: <36bcdab2dae7429d9c2162879d0a3f9a@AcuMS.aculab.com>
Date: Sat, 25 Nov 2023 15:23:49 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Kent Overstreet' <kent.overstreet@...ux.dev>, "netdev@...r.kernel.org"
<netdev@...r.kernel.org>
CC: Thomas Graf <tgraf@...g.ch>, Herbert Xu <herbert@...dor.apana.org.au>
Subject: RE: [PATCH] rhashtable: Better error message on allocation failure
From: Kent Overstreet
> Sent: 24 November 2023 00:00
>
> Memory allocation failures print backtraces by default, but when we're
> running out of a rhashtable worker the backtrace is useless - it doesn't
> tell us which hashtable the allocation failure was for.
>
> This adds a dedicated warning that prints out functions from the
> rhashtable params, which will be a bit more useful.
>
> Signed-off-by: Kent Overstreet <kent.overstreet@...ux.dev>
> Cc: Thomas Graf <tgraf@...g.ch>
> Cc: Herbert Xu <herbert@...dor.apana.org.au>
> Acked-by: Herbert Xu <herbert@...dor.apana.org.au>
> ---
> lib/rhashtable.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/lib/rhashtable.c b/lib/rhashtable.c
> index 6ae2ba8e06a2..d3fce9c8989a 100644
> --- a/lib/rhashtable.c
> +++ b/lib/rhashtable.c
> @@ -360,9 +360,14 @@ static int rhashtable_rehash_alloc(struct rhashtable *ht,
>
> ASSERT_RHT_MUTEX(ht);
>
> - new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
> - if (new_tbl == NULL)
> + new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL|__GFP_NOWARN);
> + if (new_tbl == NULL) {
> + WARN("rhashtable bucket table allocation failure for %ps",
Won't WARN() be a panic on systems with PANICK_ON_WARN set?
> + (void *) ht->p.hashfn ?:
> + (void *) ht->p.obj_hashfn ?:
> + (void *) ht->p.obj_cmpfn);
That layout is horrid (and I bet checkpatch complains).
You only actually need one (void *) cast on the RH value:
ht->p.hashfn ?: ht->p.obj_hashfn ?: (void *)ht->p.obj_cmpfn
David
> return -ENOMEM;
> + }
>
> err = rhashtable_rehash_attach(ht, old_tbl, new_tbl);
> if (err)
> --
> 2.42.0
>
-
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