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From: Hannes Reinecke <hare@suse.de>
To: dm-devel@redhat.com
Subject: Re: [PATCH V3 1/3] multipath-tools: Increase MAX_REPLY_LEN.
Date: Fri, 1 Jul 2016 16:46:53 +0200	[thread overview]
Message-ID: <5776825D.8050202@suse.de> (raw)
In-Reply-To: <20160701124656.169890-2-fge@redhat.com>

On 07/01/2016 02:46 PM, Gris Ge wrote:
> Problem:
> 
>     mpath_recv_reply() return -EINVA with 2k paths.
> 
> Root cause:
> 
>     With 2k paths(1k mpaths) simulated by scsi_debug, the 'show maps json'
>     requires 1633217 bytes while MAX_REPLY_LEN is 65535 bytes.
> 
> Fix:
> 
>     Increase MAX_REPLY_LEN to 10485760(10MiB) which is enough for 10k
>     paths.
> 
> Signed-off-by: Gris Ge <fge@redhat.com>
> ---
>  libmpathcmd/mpath_cmd.h | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/libmpathcmd/mpath_cmd.h b/libmpathcmd/mpath_cmd.h
> index f33f000..d65c648 100644
> --- a/libmpathcmd/mpath_cmd.h
> +++ b/libmpathcmd/mpath_cmd.h
> @@ -28,7 +28,9 @@ extern "C" {
>  
>  #define DEFAULT_SOCKET		"/org/kernel/linux/storage/multipathd"
>  #define DEFAULT_REPLY_TIMEOUT	1000
> -#define MAX_REPLY_LEN		65536
> +#define MAX_REPLY_LEN		10485760
> +/* ^ 10 MiB, enough for 'show maps json' command with 10k paths which
> + *   requires about 8 MiB */
>  
>  
Huh.
Can't say I like it. The limit is pretty much self-imposed, so I'd
rather bite the bullet and make it size-independent.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare@suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)

  reply	other threads:[~2016-07-01 14:46 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-28  3:52 [PATCH] Introducing multipath C API <libdmmp/libdmmp.h> Gris Ge
2016-01-28  9:15 ` Hannes Reinecke
2016-01-28  9:40   ` Gris Ge
2016-02-01 13:13   ` Todd Gill
2016-02-01 13:36     ` Hannes Reinecke
2016-02-12  8:10       ` [PATCH V2] Introducing multipath C API Gris Ge
2016-02-12  8:10         ` [PATCH V2] Introducing multipath C API <libdmmp/libdmmp.h> Gris Ge
2016-03-04 16:06           ` Benjamin Marzinski
2016-03-05  9:46             ` Gris Ge
2016-07-01 12:46           ` [PATCH V3 0/3] Introducing multipath C API Gris Ge
2016-07-01 12:46             ` [PATCH V3 1/3] multipath-tools: Increase MAX_REPLY_LEN Gris Ge
2016-07-01 14:46               ` Hannes Reinecke [this message]
2016-07-02  0:25                 ` Gris Ge
2016-07-04  6:05                   ` Hannes Reinecke
2016-07-04  9:11                     ` Gris Ge
2016-07-04  9:17                       ` [PATCH V4 0/3] Introducing multipath C API Gris Ge
2016-07-04  9:17                         ` [PATCH V4 1/3] multipath-tools: New way to limit the IPC command length Gris Ge
2016-07-04  9:17                         ` [PATCH V4 2/3] multipath-tools: Set errno mpath_recv_reply() when failure Gris Ge
2016-07-04  9:17                         ` [PATCH V4 3/3] multipath-tools: Introducing multipath C API Gris Ge
2016-07-04  9:27                         ` [PATCH V4 0/3] " Gris Ge
2016-07-04  9:29                         ` Please ignore this patch set. ([PATCH V4 0/3] Introducing multipath C API) Gris Ge
2016-07-04  9:40                         ` [PATCH V5 0/3] Introducing multipath C API Gris Ge
2016-07-04  9:40                           ` [PATCH V5 1/3] multipath-tools: New way to limit the IPC command length Gris Ge
2016-07-04  9:40                           ` [PATCH V5 2/3] multipath-tools: Set errno mpath_recv_reply() when failure Gris Ge
2016-07-04  9:40                           ` [PATCH V5 3/3] multipath-tools: Introducing multipath C API Gris Ge
2016-07-01 12:46             ` [PATCH V3 2/3] multipath-tools: Set errno mpath_recv_reply() when failure Gris Ge
2016-07-01 12:46             ` [PATCH V3 3/3] multipath-tools: Introducing multipath C API <libdmmp/libdmmp.h> Gris Ge
2016-07-01 12:55             ` [PATCH " Gris Ge
2016-07-01 13:06             ` [PATCH V3 " Gris Ge
2016-07-12  6:50 ` [PATCH V6 0/3] Introducing multipath C API Gris Ge
2016-07-12  6:50   ` [PATCH V6 1/3] multipath-tools: New way to limit the IPC command length Gris Ge
2016-07-15 21:35     ` Benjamin Marzinski
2016-07-18 12:38       ` Gris Ge
2016-08-12 15:57       ` Bart Van Assche
2016-08-12 21:35         ` Benjamin Marzinski
2016-08-12 21:49           ` Bart Van Assche
2016-07-12  6:50   ` [PATCH V6 2/3] multipath-tools: Set errno mpath_recv_reply() when failure Gris Ge
2016-07-12  6:50   ` [PATCH V6 3/3] multipath-tools: Introducing multipath C API Gris Ge
2016-07-15 21:36   ` [PATCH V6 0/3] " Benjamin Marzinski
2016-08-12 12:12 ` [PATCH V7 0/4] multipath: " Gris Ge
2016-08-12 12:12   ` [PATCH V7 1/4] libmpathcmd: Block SIGPIPE when write() Gris Ge
2016-08-12 16:01     ` Bart Van Assche
2016-08-12 12:12   ` [PATCH V7 2/4] multipath-tools: New way to limit the IPC command length Gris Ge
2016-08-12 15:48     ` Bart Van Assche
2016-08-12 21:53     ` Benjamin Marzinski
2016-08-12 12:12   ` [PATCH V7 3/4] multipath-tools: Set errno mpath_recv_reply() when failure Gris Ge
2016-08-12 12:12   ` [PATCH V7 4/4] multipath-tools: Introducing multipath C API Gris Ge
2017-02-24 12:50     ` [PATCH V5] " Gris Ge
2017-02-27  5:56       ` Christophe Varoqui
2017-02-24 13:07     ` Gris Ge
2016-08-12 13:26   ` [PATCH V7 0/4] multipath: " Gris Ge

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