netdev - Re: iproute uses too small of a receive buffer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20091028.005559.92092291.davem@davemloft.net>
Date:	Wed, 28 Oct 2009 00:55:59 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	shemminger@...tta.com, greearb@...delatech.com,
	netdev@...r.kernel.org
Subject: Re: iproute uses too small of a receive buffer

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Wed, 28 Oct 2009 08:52:57 +0100

> Stephen Hemminger a écrit :
>> 
>> Just having larger buffer isn't guarantee of success. Allocating
>> a huge buffer is not going to work on embedded.
>> 
> 
> Please note we do not allocate a big buffer, only allow more small skbs
> to be queued on socket receive queue.
> 
> If memory is not available, skb allocation will eventually fail
> and be reported as well, embedded or not.
> 
> I vote for allowing 1024*1024 bytes instead of 32768,
> and eventually user should be warned that it is capped by 
> /proc/sys/net/core/rmem_max

This discussion constantly reminds me of:

/*
 *	skb should fit one page. This choice is good for headerless malloc.
 *	But we should limit to 8K so that userspace does not have to
 *	use enormous buffer sizes on recvmsg() calls just to avoid
 *	MSG_TRUNC when PAGE_SIZE is very large.
 */
#if PAGE_SIZE < 8192UL
#define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(PAGE_SIZE)
#else
#define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(8192UL)
#endif

#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html