[PATCH 1/5] Add AIO event ring size tunable

[PATCH 1/5] Add AIO event ring size tunable

[Sébastien Dugué]

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aiomaxevents :

 This patch adds a posix_aio_default_maxevents sysctl variable for configuring the
default AIO context event ring size at runtime. This way, calling sys_io_setup with
nr_events=0, will result in the kernel using the default system value.

 This tunable is accessible via /proc/sys/fs/posix-aio-default-max-nr.

 Makefile               |    2 +-
 fs/Kconfig             |    8 ++++++++
 fs/aio.c               |    8 ++++++++
 include/linux/aio.h    |    3 +++
 include/linux/sysctl.h |    3 +++
 kernel/sysctl.c        |   10 ++++++++++
 6 files changed, 33 insertions(+), 1 deletion(-)

Signed-off-by: Sébastien Dugué <sebastien.dugue@bull.net>

Index: linux-2.6.12/fs/aio.c
===================================================================
--- linux-2.6.12.orig/fs/aio.c	2005-06-23 13:58:03.000000000 +0200
+++ linux-2.6.12/fs/aio.c	2005-06-23 13:59:08.000000000 +0200
@@ -43,6 +43,9 @@
 /*------ sysctl variables----*/
 atomic_t aio_nr = ATOMIC_INIT(0);	/* current system wide number of aio requests */
 unsigned aio_max_nr = 0x10000;	/* system wide maximum number of aio requests */
+#if defined(CONFIG_POSIX_AIO)
+unsigned posix_aio_default_maxevents = 1024; /* FIXME: default value for POSIX AIO */
+#endif /* CONFIG_POSIX_AIO */
 /*----end sysctl variables---*/
 
 static kmem_cache_t	*kiocb_cachep;
@@ -1244,6 +1247,11 @@
 	unsigned long ctx;
 	long ret;
 
+#if defined(CONFIG_POSIX_AIO)
+	if (nr_events == 0)
+		nr_events = posix_aio_default_maxevents;
+#endif
+
 	ret = get_user(ctx, ctxp);
 	if (unlikely(ret))
 		goto out;
Index: linux-2.6.12/fs/Kconfig
===================================================================
--- linux-2.6.12.orig/fs/Kconfig	2005-06-23 13:58:03.000000000 +0200
+++ linux-2.6.12/fs/Kconfig	2005-06-23 13:59:08.000000000 +0200
@@ -4,6 +4,14 @@
 
 menu "File systems"
 
+config POSIX_AIO
+	bool "POSIX AIO Support"
+	help
+	  Enable POSIX Asynchronous IO
+
+	  If unsure, say N.
+
+
 config EXT2_FS
 	tristate "Second extended fs support"
 	help
Index: linux-2.6.12/include/linux/aio.h
===================================================================
--- linux-2.6.12.orig/include/linux/aio.h	2005-06-23 13:58:03.000000000 +0200
+++ linux-2.6.12/include/linux/aio.h	2005-06-23 13:59:08.000000000 +0200
@@ -153,6 +153,9 @@
 
 /* prototypes */
 extern unsigned aio_max_size;
+#if defined(CONFIG_POSIX_AIO)
+extern unsigned posix_aio_default_maxevents;
+#endif /* CONFIG_POSIX_AIO */
 
 extern ssize_t FASTCALL(wait_on_sync_kiocb(struct kiocb *iocb));
 extern int FASTCALL(aio_put_req(struct kiocb *iocb));
Index: linux-2.6.12/include/linux/sysctl.h
===================================================================
--- linux-2.6.12.orig/include/linux/sysctl.h	2005-06-23 13:58:03.000000000 +0200
+++ linux-2.6.12/include/linux/sysctl.h	2005-06-23 13:59:08.000000000 +0200
@@ -680,6 +680,9 @@
 	FS_XFS=17,	/* struct: control xfs parameters */
 	FS_AIO_NR=18,	/* current system-wide number of aio requests */
 	FS_AIO_MAX_NR=19,	/* system-wide maximum number of aio requests */
+#if defined(CONFIG_POSIX_AIO)
+	FS_POSIX_AIO_MAX_NR=20,	/* default value for POSIX AIO max request */
+#endif /* CONFIG_POSIX_AIO */
 };
 
 /* /proc/sys/fs/quota/ */
Index: linux-2.6.12/kernel/sysctl.c
===================================================================
--- linux-2.6.12.orig/kernel/sysctl.c	2005-06-23 13:58:03.000000000 +0200
+++ linux-2.6.12/kernel/sysctl.c	2005-06-23 13:59:08.000000000 +0200
@@ -949,6 +949,16 @@
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec,
 	},
+#if defined(CONFIG_POSIX_AIO)
+	{
+		.ctl_name	= FS_POSIX_AIO_MAX_NR,
+		.procname	= "posix-aio-default-max-nr",
+		.data		= &posix_aio_default_maxevents,
+		.maxlen		= sizeof(posix_aio_default_maxevents),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
+#endif /* CONFIG_POSIX_AIO */
 #endif
 	{ .ctl_name = 0 }
 };
Index: linux-2.6.12/Makefile
===================================================================
--- linux-2.6.12.orig/Makefile	2005-06-23 13:58:03.000000000 +0200
+++ linux-2.6.12/Makefile	2005-06-23 13:59:08.000000000 +0200
@@ -1,7 +1,7 @@
 VERSION = 2
 PATCHLEVEL = 6
 SUBLEVEL = 12
-EXTRAVERSION =
+EXTRAVERSION = .PAIO-aiomaxevents
 NAME=Woozy Numbat
 
 # *DOCUMENTATION*

Re: [PATCH 1/5] Add AIO event ring size tunable

[Trond Myklebust]

to den 28.07.2005 Klokka 17:46 (+0200) skreiv Sébastien Dugué:
> 
> 
> 
> 
> 
> 
> 
> ukjent vedlegg
> (aiomaxevents)

Please don't post these patches as base-64 encoded anonymous
attachments. It makes them very annoying to review.

In you must use attachments, use inlined ascii. Better still, don't use
attachments at all, but just include the patch in the body of your
email.

Cheers,
  Trond

Re: [PATCH 1/5] Add AIO event ring size tunable

[Sébastien Dugué]

On Thu, 2005-07-28 at 12:52 -0400, Trond Myklebust wrote:
> to den 28.07.2005 Klokka 17:46 (+0200) skreiv Sébastien Dugué:
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > ukjent vedlegg
> > (aiomaxevents)
> 
> Please don't post these patches as base-64 encoded anonymous
> attachments. It makes them very annoying to review.
> 
> In you must use attachments, use inlined ascii. Better still, don't use
> attachments at all, but just include the patch in the body of your
> email.
> 
> Cheers,
>   Trond
> 

  Argh, I usually use sylpheed to post patches, but forgot this
time. If someone wants me to resend, just ask.

  Sébastien.

-- 
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  Sébastien Dugué                BULL/FREC:B1-247
  phone: (+33) 476 29 77 70      Bullcom: 229-7770

  mailto:sebastien.dugue@bull.net

  Linux POSIX AIO: http://www.bullopensource.org/posix
  
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