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Message-ID: <20100105032715.GA1044@localhost>
Date: Tue, 5 Jan 2010 11:27:15 +0800
From: Wu Fengguang <fengguang.wu@...el.com>
To: Stephen Rothwell <sfr@...b.auug.org.au>
Cc: Christoph Hellwig <hch@...radead.org>,
Andi Kleen <andi@...stfloor.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Quentin Barnes <qbarnes+nfs@...oo-inc.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
Nick Piggin <npiggin@...e.de>,
Steven Whitehouse <swhiteho@...hat.com>,
David Howells <dhowells@...hat.com>,
Al Viro <viro@...iv.linux.org.uk>,
Jonathan Corbet <corbet@....net>,
Eric Paris <eparis@...hat.com>
Subject: Re: [RFC][PATCH v5] readahead: introduce O_RANDOM for
POSIX_FADV_RANDOM
On Tue, Jan 05, 2010 at 11:18:01AM +0800, Wu Fengguang wrote:
>
> +/*
> + * usage of open(O_RANDOM) is disabled: __dentry_open() will nuke this bit
> + */
> +#ifndef O_RANDOM
> +#define O_RANDOM 0200000000 /* random access pattern hint */
> +#endif
> +
Tested with this program, output is
flags=0x9001 O_SYNC=0x1000 O_RANDOM=0
My user space O_SYNC is still the old O_DSYNC. But should be OK to
test the sparc O_SYNC.
------------------------------------------------------------------------------
#include <fcntl.h>
#include <stdio.h>
#define O_RANDOM 040000000 /* random access pattern hint */
int main (void)
{
int fd, flags;
fd = open("/tmp/fcntl-test",
O_WRONLY | O_CREAT | O_SYNC | O_RANDOM, 0666);
flags = fcntl(fd, F_GETFL, 0);
printf("flags=%#lx O_SYNC=%#lx O_RANDOM=%#lx\n",
flags, flags & O_SYNC, flags & O_RANDOM);
}
------------------------------------------------------------------------------
Thanks,
Fengguang
--
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