Revision d7831a0bdf06b9f722b947bb0c205ff7d77cebd8 authored by Richard Kennedy on 30 June 2009, 18:41:35 UTC, committed by Linus Torvalds on 01 July 2009, 01:56:01 UTC
balance_dirty_pages can overreact and move all of the dirty pages to writeback unnecessarily. balance_dirty_pages makes its decision to throttle based on the number of dirty plus writeback pages that are over the calculated limit,so it will continue to move pages even when there are plenty of pages in writeback and less than the threshold still dirty. This allows it to overshoot its limits and move all the dirty pages to writeback while waiting for the drives to catch up and empty the writeback list. A simple fio test easily demonstrates this problem. fio --name=f1 --directory=/disk1 --size=2G -rw=write --name=f2 --directory=/disk2 --size=1G --rw=write --startdelay=10 This is the simplest fix I could find, but I'm not entirely sure that it alone will be enough for all cases. But it certainly is an improvement on my desktop machine writing to 2 disks. Do we need something more for machines with large arrays where bdi_threshold * number_of_drives is greater than the dirty_ratio ? Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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au1000_generic.h
/*
* Alchemy Semi Au1000 pcmcia driver include file
*
* Copyright 2001 MontaVista Software Inc.
* Author: MontaVista Software, Inc.
* ppopov@mvista.com or source@mvista.com
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
*/
#ifndef __ASM_AU1000_PCMCIA_H
#define __ASM_AU1000_PCMCIA_H
/* include the world */
#include <pcmcia/cs_types.h>
#include <pcmcia/cs.h>
#include <pcmcia/ss.h>
#include <pcmcia/cistpl.h>
#include "cs_internal.h"
#define AU1000_PCMCIA_POLL_PERIOD (2*HZ)
#define AU1000_PCMCIA_IO_SPEED (255)
#define AU1000_PCMCIA_MEM_SPEED (300)
#define AU1X_SOCK0_IO 0xF00000000ULL
#define AU1X_SOCK0_PHYS_ATTR 0xF40000000ULL
#define AU1X_SOCK0_PHYS_MEM 0xF80000000ULL
/* pseudo 32 bit phys addresses, which get fixed up to the
* real 36 bit address in fixup_bigphys_addr() */
#define AU1X_SOCK0_PSEUDO_PHYS_ATTR 0xF4000000
#define AU1X_SOCK0_PSEUDO_PHYS_MEM 0xF8000000
/* pcmcia socket 1 needs external glue logic so the memory map
* differs from board to board.
*/
#if defined(CONFIG_MIPS_PB1000) || defined(CONFIG_MIPS_PB1100) || \
defined(CONFIG_MIPS_PB1500) || defined(CONFIG_MIPS_PB1550) || \
defined(CONFIG_MIPS_PB1200)
#define AU1X_SOCK1_IO 0xF08000000ULL
#define AU1X_SOCK1_PHYS_ATTR 0xF48000000ULL
#define AU1X_SOCK1_PHYS_MEM 0xF88000000ULL
#define AU1X_SOCK1_PSEUDO_PHYS_ATTR 0xF4800000
#define AU1X_SOCK1_PSEUDO_PHYS_MEM 0xF8800000
#elif defined(CONFIG_MIPS_DB1000) || defined(CONFIG_MIPS_DB1100) || \
defined(CONFIG_MIPS_DB1500) || defined(CONFIG_MIPS_DB1550) || \
defined(CONFIG_MIPS_DB1200)
#define AU1X_SOCK1_IO 0xF04000000ULL
#define AU1X_SOCK1_PHYS_ATTR 0xF44000000ULL
#define AU1X_SOCK1_PHYS_MEM 0xF84000000ULL
#define AU1X_SOCK1_PSEUDO_PHYS_ATTR 0xF4400000
#define AU1X_SOCK1_PSEUDO_PHYS_MEM 0xF8400000
#endif
struct pcmcia_state {
unsigned detect: 1,
ready: 1,
wrprot: 1,
bvd1: 1,
bvd2: 1,
vs_3v: 1,
vs_Xv: 1;
};
struct pcmcia_configure {
unsigned sock: 8,
vcc: 8,
vpp: 8,
output: 1,
speaker: 1,
reset: 1;
};
struct pcmcia_irqs {
int sock;
int irq;
const char *str;
};
struct au1000_pcmcia_socket {
struct pcmcia_socket socket;
/*
* Info from low level handler
*/
struct device *dev;
unsigned int nr;
unsigned int irq;
/*
* Core PCMCIA state
*/
struct pcmcia_low_level *ops;
unsigned int status;
socket_state_t cs_state;
unsigned short spd_io[MAX_IO_WIN];
unsigned short spd_mem[MAX_WIN];
unsigned short spd_attr[MAX_WIN];
struct resource res_skt;
struct resource res_io;
struct resource res_mem;
struct resource res_attr;
void * virt_io;
unsigned int phys_io;
unsigned int phys_attr;
unsigned int phys_mem;
unsigned short speed_io, speed_attr, speed_mem;
unsigned int irq_state;
struct timer_list poll_timer;
};
struct pcmcia_low_level {
struct module *owner;
int (*hw_init)(struct au1000_pcmcia_socket *);
void (*hw_shutdown)(struct au1000_pcmcia_socket *);
void (*socket_state)(struct au1000_pcmcia_socket *, struct pcmcia_state *);
int (*configure_socket)(struct au1000_pcmcia_socket *, struct socket_state_t *);
/*
* Enable card status IRQs on (re-)initialisation. This can
* be called at initialisation, power management event, or
* pcmcia event.
*/
void (*socket_init)(struct au1000_pcmcia_socket *);
/*
* Disable card status IRQs and PCMCIA bus on suspend.
*/
void (*socket_suspend)(struct au1000_pcmcia_socket *);
};
extern int au1x_board_init(struct device *dev);
#endif /* __ASM_AU1000_PCMCIA_H */
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