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From: NeilBrown <neilb@suse.com>
To: Davidlohr Bueso <dave@stgolabs.net>,
	akpm@linux-foundation.org, torvalds@linux-foundation.org
Cc: tgraf@suug.ch, herbert@gondor.apana.org.au,
	manfred@colorfullife.com, mhocko@kernel.org,
	guillaume.knispel@supersonicimagine.com,
	linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
	dave@stgolabs.net, Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH 1/4] lib/rhashtable: simplify bucket_table_alloc()
Date: Fri, 22 Jun 2018 16:04:29 +1000	[thread overview]
Message-ID: <87sh5fbbma.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <20180621212825.3059-2-dave@stgolabs.net>

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On Thu, Jun 21 2018, Davidlohr Bueso wrote:

> As of ce91f6ee5 (mm: kvmalloc does not fallback to vmalloc for incompatible gfp flag),
> we can simplify the caller and trust kvzalloc() to just do the right thing.

Hi,
 it isn't clear to me that this is true.
 With this change we lose __GFP_NOWARN and __GFP_NORETRY.
 I doubt the NORETRY is particularly important as this is if it
 isn't GFP_KERNEL, then it is GFP_ATOMIC which doesn't retry anyway.
 However I cannot see why this patch won't result in warnings when the
 kzalloc() fails.
 What am I missing?

Thanks,
NeilBrown


>
> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> ---
>  lib/rhashtable.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/lib/rhashtable.c b/lib/rhashtable.c
> index 9427b5766134..26c9cd8a985a 100644
> --- a/lib/rhashtable.c
> +++ b/lib/rhashtable.c
> @@ -175,10 +175,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
>  	int i;
>  
>  	size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
> -	if (gfp != GFP_KERNEL)
> -		tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY);
> -	else
> -		tbl = kvzalloc(size, gfp);
> +	tbl = kvzalloc(size, gfp);
>  
>  	size = nbuckets;
>  
> -- 
> 2.16.4

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WARNING: multiple messages have this Message-ID (diff)
From: NeilBrown <neilb@suse.com>
To: akpm@linux-foundation.org, torvalds@linux-foundation.org
Cc: tgraf@suug.ch, herbert@gondor.apana.org.au,
	manfred@colorfullife.com, mhocko@kernel.org,
	guillaume.knispel@supersonicimagine.com,
	linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
	dave@stgolabs.net, Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH 1/4] lib/rhashtable: simplify bucket_table_alloc()
Date: Fri, 22 Jun 2018 16:04:29 +1000	[thread overview]
Message-ID: <87sh5fbbma.fsf@notabene.neil.brown.name> (raw)
In-Reply-To: <20180621212825.3059-2-dave@stgolabs.net>

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On Thu, Jun 21 2018, Davidlohr Bueso wrote:

> As of ce91f6ee5 (mm: kvmalloc does not fallback to vmalloc for incompatible gfp flag),
> we can simplify the caller and trust kvzalloc() to just do the right thing.

Hi,
 it isn't clear to me that this is true.
 With this change we lose __GFP_NOWARN and __GFP_NORETRY.
 I doubt the NORETRY is particularly important as this is if it
 isn't GFP_KERNEL, then it is GFP_ATOMIC which doesn't retry anyway.
 However I cannot see why this patch won't result in warnings when the
 kzalloc() fails.
 What am I missing?

Thanks,
NeilBrown


>
> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> ---
>  lib/rhashtable.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/lib/rhashtable.c b/lib/rhashtable.c
> index 9427b5766134..26c9cd8a985a 100644
> --- a/lib/rhashtable.c
> +++ b/lib/rhashtable.c
> @@ -175,10 +175,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
>  	int i;
>  
>  	size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]);
> -	if (gfp != GFP_KERNEL)
> -		tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY);
> -	else
> -		tbl = kvzalloc(size, gfp);
> +	tbl = kvzalloc(size, gfp);
>  
>  	size = nbuckets;
>  
> -- 
> 2.16.4

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  parent reply	other threads:[~2018-06-22  6:04 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-21 21:28 [PATCH -next v3 0/4] rhashtable: guarantee initial allocation Davidlohr Bueso
2018-06-21 21:28 ` [PATCH 1/4] lib/rhashtable: simplify bucket_table_alloc() Davidlohr Bueso
2018-06-21 21:33   ` Randy Dunlap
2018-06-22  6:04   ` NeilBrown [this message]
2018-06-22  6:04     ` NeilBrown
2018-06-22  6:36     ` Davidlohr Bueso
2018-06-22 18:15   ` [PATCH v2 " Davidlohr Bueso
2018-06-22 18:16     ` Davidlohr Bueso
2018-06-22 18:35     ` Davidlohr Bueso
2018-06-25  9:13     ` Michal Hocko
2018-06-21 21:28 ` [PATCH 2/4] lib/rhashtable: guarantee initial hashtable allocation Davidlohr Bueso
2018-06-22  6:54   ` Herbert Xu
2018-06-21 21:28 ` [PATCH 3/4] ipc: get rid of ids->tables_initialized hack Davidlohr Bueso
2018-06-21 21:28 ` [PATCH 4/4] ipc: simplify ipc initialization Davidlohr Bueso

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