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From: Andrew Morton <akpm@linux-foundation.org>
To: Nadia.Derbey@bull.net
Cc: linux-kernel@vger.kernel.org, y-goto@jp.fujitsu.com,
	linux-mm@kvack.org, containers@lists.linux-foundation.org,
	matthltc@us.ibm.com, cmm@us.ibm.com, Nadia.Derbey@bull.net
Subject: Re: [PATCH 8/8] Re-enable msgmni automatic recomputing msgmni if set to negative
Date: Mon, 11 Feb 2008 12:27:48 -0800	[thread overview]
Message-ID: <20080211122748.64e7bc36.akpm@linux-foundation.org> (raw)
In-Reply-To: <20080211141816.520049000@bull.net>

On Mon, 11 Feb 2008 15:16:54 +0100
Nadia.Derbey@bull.net wrote:

> [PATCH 08/08]
> 
> This patch is the enhancement as asked for by Yasunori: if msgmni is set to
> a negative value, register it back into the ipcns notifier chain.
> 
> A new interface has been added to the notification mechanism:
> notifier_chain_cond_register() registers a notifier block only if not already
> registered. With that new interface we avoid taking care of the states changes
> in procfs.
> 
> ...
>
>  static int proc_ipc_callback_dointvec(ctl_table *table, int write,
>  	struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
>  {
> +	struct ctl_table ipc_table;
>  	size_t lenp_bef = *lenp;
>  	int rc;
>  
> -	rc = proc_ipc_dointvec(table, write, filp, buffer, lenp, ppos);
> +	memcpy(&ipc_table, table, sizeof(ipc_table));
> +	ipc_table.data = get_ipc(table);
> +
> +	rc = proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
>  
>  	if (write && !rc && lenp_bef == *lenp)
> -		/*
> -		 * Tunable has successfully been changed from userland:
> -		 * disable its automatic recomputing.
> -		 */
> -		unregister_ipcns_notifier(current->nsproxy->ipc_ns);
> +		tunable_set_callback(*((int *)(ipc_table.data)));
>  
>  	return rc;
>  }
> @@ -119,12 +142,14 @@ static int sysctl_ipc_registered_data(ct
>  	rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval,
>  		newlen);
>  
> -	if (newval && newlen && rc > 0)
> +	if (newval && newlen && rc > 0) {
>  		/*
> -		 * Tunable has successfully been changed from userland:
> -		 * disable its automatic recomputing.
> +		 * Tunable has successfully been changed from userland
>  		 */
> -		unregister_ipcns_notifier(current->nsproxy->ipc_ns);
> +		int *data = get_ipc(table);
> +
> +		tunable_set_callback(*data);
> +	}
>  
>  	return rc;
>  }

hm, what's happening here?  We take a local copy of the caller's ctl_table
and then pass that into proc_dointvec().  Is that as hacky as it seems??



  reply	other threads:[~2008-02-11 20:44 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-11 14:16 [PATCH 0/8] Change default MSGMNI tunable to scale with lowmem (v3) Nadia.Derbey
2008-02-11 14:16 ` [PATCH 1/8] Scaling msgmni to the amount of lowmem Nadia.Derbey
2008-02-16  5:59   ` Andrew Morton
2008-02-18  9:19     ` Nadia Derbey
2008-02-18 13:08       ` Nadia Derbey
2008-02-19  8:50         ` [LTP] " Subrata Modak
2008-02-19 17:16           ` Nadia Derbey
2008-02-19 22:16             ` Matt Helsley
2008-02-21  8:39               ` Nadia Derbey
2008-02-21 12:36               ` Nadia Derbey
2008-02-21 13:02                 ` Nadia Derbey
2008-02-21 13:39                   ` Subrata Modak
2008-02-22  6:25                     ` Nadia Derbey
2008-02-22  8:41                       ` Subrata Modak
2008-02-20  9:44             ` Subrata Modak
2008-04-29 20:28   ` Tony Luck
2008-05-05  8:45     ` Nadia Derbey
2008-05-06 16:42       ` Luck, Tony
2008-05-06 18:05         ` Serge E. Hallyn
2008-05-07  5:37           ` Nadia Derbey
2008-05-07 13:17             ` Serge E. Hallyn
2008-05-07 18:12               ` Matt Helsley
2008-05-07  5:13         ` Nadia Derbey
2008-02-11 14:16 ` [PATCH 2/8] Scaling msgmni to the number of ipc namespaces Nadia.Derbey
2008-02-11 14:16 ` [PATCH 3/8] Defining the slab_memory_callback priority as a constant Nadia.Derbey
2008-02-11 14:16 ` [PATCH 4/8] Recomputing msgmni on memory add / remove Nadia.Derbey
2008-02-11 14:16 ` [PATCH 5/8] Invoke the ipcns notifier chain as a work item Nadia.Derbey
2008-02-11 14:16 ` [PATCH 6/8] Recomputing msgmni on ipc namespace creation/removal Nadia.Derbey
2008-02-11 14:16 ` [PATCH 7/8] Do not recompute msgmni anymore if explicitely set by user Nadia.Derbey
2008-02-11 20:24   ` Andrew Morton
2008-02-12  9:32     ` Nadia Derbey
2008-02-12  9:44       ` Andrew Morton
2008-02-12 15:15         ` Nadia Derbey
2008-02-12 19:44           ` Andrew Morton
2008-02-14 11:47             ` Nadia Derbey
2008-02-12  9:45       ` Nadia Derbey
2008-02-11 14:16 ` [PATCH 8/8] Re-enable msgmni automatic recomputing msgmni if set to negative Nadia.Derbey
2008-02-11 20:27   ` Andrew Morton [this message]
2008-02-12 11:38     ` Nadia Derbey

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