Re: [PATCH] Make I/O schedulers optional (Was: Re: Kernel 2.6 size increase)

From: Bernardo Innocenti <bernie@develer.com>
To: Andrew Morton <akpm@osdl.org>
Cc: hch@infradead.org, willy@w.ods.org, hch@lst.de,
	uclinux-dev@uclinux.org, linux-kernel@vger.kernel.org,
	alan@lxorguk.ukuu.org.uk, axboe@suse.de
Subject: Re: [PATCH] Make I/O schedulers optional (Was: Re: Kernel 2.6 size increase)
Date: Sat, 26 Jul 2003 14:40:51 +0200	[thread overview]
Message-ID: <200307261440.52002.bernie@develer.com> (raw)
In-Reply-To: <20030726011708.6aa29641.akpm@osdl.org>

On Saturday 26 July 2003 10:17, Andrew Morton wrote:

> >   Here it is, attached below. I've tested it on both i386 and m68knommu.
>
> Is nice, but I wonder if it should be appearing under the
>
> 	General Setup  ->  Remove kernel features
>
> menu?  ie: CONFIG_EMBEDDED.

Right. Here is an updated patch. I think I've now tested it properly even
with the noop scheduler on i386. Please apply.

--------------------------------------------------------------------------

Add kconfig options to allow excluding either or both the I/O schedulers.
Mostly useful for embedded systems (save ~13KB):

With my desktop PC (i386) kernel:

   text    data     bss     dec     hex filename
   2210707  475856  150444 2837007  2b4a0f vmlinux_with_ioscheds
   2197763  473446  150380 2821589  2b0dd5 vmlinux_without_ioscheds

With my uClinux (m68knommu) kernel:

   text    data     bss     dec     hex filename
   807760   47384   78884  934028   e408c linux_without_ioscheds
   819276   52460   78896  950632   e8168 linux_with_ioscheds


diff -Nru linux-2.6.0-test1.orig/drivers/block/Kconfig.iosched linux-2.6.0-test1-with_elevator_patch/drivers/block/Kconfig.iosched

--- linux-2.6.0-test1.orig/drivers/block/Kconfig.iosched	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.0-test1-with_elevator_patch/drivers/block/Kconfig.iosched	2003-07-26 14:25:44.000000000 +0200
@@ -0,0 +1,8 @@
+config IOSCHED_AS
+	bool "Anticipatory I/O scheduler" if EMBEDDED
+	default y
+
+config IOSCHED_DEADLINE
+	bool "Deadline I/O scheduler" if EMBEDDED
+	default y
+
diff -Nru linux-2.6.0-test1.orig/drivers/block/Makefile linux-2.6.0-test1-with_elevator_patch/drivers/block/Makefile
--- linux-2.6.0-test1.orig/drivers/block/Makefile	2003-07-14 05:37:16.000000000 +0200
+++ linux-2.6.0-test1-with_elevator_patch/drivers/block/Makefile	2003-07-25 20:21:50.000000000 +0200
@@ -13,9 +13,10 @@
 # kblockd threads
 #
 
-obj-y	:= elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o \
-	deadline-iosched.o as-iosched.o
+obj-y	:= elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o
 
+obj-$(CONFIG_IOSCHED_AS)	+= as-iosched.o
+obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
 obj-$(CONFIG_MAC_FLOPPY)	+= swim3.o
 obj-$(CONFIG_BLK_DEV_FD)	+= floppy.o
 obj-$(CONFIG_BLK_DEV_FD98)	+= floppy98.o
diff -Nru linux-2.6.0-test1.orig/drivers/block/as-iosched.c linux-2.6.0-test1-with_elevator_patch/drivers/block/as-iosched.c
--- linux-2.6.0-test1.orig/drivers/block/as-iosched.c	2003-07-14 05:28:54.000000000 +0200
+++ linux-2.6.0-test1-with_elevator_patch/drivers/block/as-iosched.c	2003-07-25 20:19:44.000000000 +0200
@@ -1,7 +1,7 @@
 /*
  *  linux/drivers/block/as-iosched.c
  *
- *  Anticipatory & deadline i/o scheduler.
+ *  Anticipatory i/o scheduler.
  *
  *  Copyright (C) 2002 Jens Axboe <axboe@suse.de>
  *                     Nick Piggin <piggin@cyberone.com.au>
@@ -1832,6 +1832,7 @@
 	.elevator_exit_fn =		as_exit,
 
 	.elevator_ktype =		&as_ktype,
+	.elevator_name =		"anticipatory scheduling",
 };
 
 EXPORT_SYMBOL(iosched_as);
diff -Nru linux-2.6.0-test1.orig/drivers/block/deadline-iosched.c linux-2.6.0-test1-with_elevator_patch/drivers/block/deadline-iosched.c
--- linux-2.6.0-test1.orig/drivers/block/deadline-iosched.c	2003-07-14 05:37:15.000000000 +0200
+++ linux-2.6.0-test1-with_elevator_patch/drivers/block/deadline-iosched.c	2003-07-25 20:20:53.000000000 +0200
@@ -941,6 +941,7 @@
 	.elevator_exit_fn =		deadline_exit,
 
 	.elevator_ktype =		&deadline_ktype,
+	.elevator_name =		"deadline",
 };
 
 EXPORT_SYMBOL(iosched_deadline);
diff -Nru linux-2.6.0-test1.orig/drivers/block/elevator.c linux-2.6.0-test1-with_elevator_patch/drivers/block/elevator.c
--- linux-2.6.0-test1.orig/drivers/block/elevator.cator_name =	2003-07-14 05:36:48.000000000 +0200
+++ linux-2.6.0-test1-with_elevator_patch/drivers/block/elevator.c	2003-07-25 19:27:41.000000000 +0200
@@ -409,6 +409,7 @@
 	.elevator_merge_req_fn		= elevator_noop_merge_requests,
 	.elevator_next_req_fn		= elevator_noop_next_request,
 	.elevator_add_req_fn		= elevator_noop_add_request,
+	.elevator_name			= "noop",
 };
 
 module_init(elevator_global_init);
diff -Nru linux-2.6.0-test1.orig/drivers/block/ll_rw_blk.c linux-2.6.0-test1-with_elevator_patch/drivers/block/ll_rw_blk.c
--- linux-2.6.0-test1.orig/drivers/block/ll_rw_blk.c	2003-07-14 05:30:40.000000000 +0200
+++ linux-2.6.0-test1-with_elevator_patch/drivers/block/ll_rw_blk.c	2003-07-25 19:27:02.000000000 +0200
@@ -1205,17 +1205,31 @@
 
 static int __make_request(request_queue_t *, struct bio *);
 
-static elevator_t *chosen_elevator = &iosched_as;
+static elevator_t *chosen_elevator =
+#if defined(CONFIG_IOSCHED_AS)
+	&iosched_as;
+#elif defined(CONFIG_IOSCHED_DEADLINE)
+	&iosched_deadline;
+#else
+	&elevator_noop;
+#endif
 
+#if defined(CONFIG_IOSCHED_AS) || defined(CONFIG_IOSCHED_DEADLINE)
 static int __init elevator_setup(char *str)
 {
+#ifdef CONFIG_IOSCHED_DEADLINE
 	if (!strcmp(str, "deadline"))
 		chosen_elevator = &iosched_deadline;
+#endif
+#ifdef CONFIG_IOSCHED_AS
 	if (!strcmp(str, "as"))
 		chosen_elevator = &iosched_as;
+#endif
 	return 1;
 }
+
 __setup("elevator=", elevator_setup);
+#endif /* CONFIG_IOSCHED_AS || CONFIG_IOSCHED_DEADLINE */
 ator_name =
 /**
  * blk_init_queue  - prepare a request queue for use with a block device
@@ -1255,10 +1269,7 @@
 
 	if (!printed) {
 		printed = 1;
-		if (chosen_elevator == &iosched_deadline)
-			printk("deadline elevator\n");
-		else if (chosen_elevator == &iosched_as)
-			printk("anticipatory scheduling elevator\n");
+		printk("Using %s elevator\n", chosen_elevator->elevator_name);
 	}
 
 	if ((ret = elevator_init(q, chosen_elevator))) {
diff -Nru linux-2.6.0-test1.orig/init/Kconfig linux-2.6.0-test1-with_elevator_patch/init/Kconfig
--- linux-2.6.0-test1.orig/init/Kconfig	2003-07-14 05:37:16.000000000 +0200
+++ linux-2.6.0-test1-with_elevator_patch/init/Kconfig	2003-07-26 14:25:48.000000000 +0200
@@ -141,6 +141,8 @@
 	  Disabling this option will cause the kernel to be built without
 	  support for epoll family of system calls.
 
+source "drivers/block/Kconfig.iosched"
+
 endmenu		# General setup
 
 
diff -Nru linux-2.6.0-test1.orig/include/linux/elevator.h linux-2.6.0-test1/include/linux/elevator.h
--- linux-2.6.0-test1.orig/include/linux/elevator.h	2003-07-14 05:29:27.000000000 +0200
+++ linux-2.6.0-test1/include/linux/elevator.h	2003-07-25 19:18:39.000000000 +0200
@@ -52,6 +52,7 @@
 
 	struct kobject kobj;
 	struct kobj_type *elevator_ktype;
+	const char *elevator_name;
 };
 
 /*

-- 
  // Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/  http://www.develer.com/

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