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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cirrus.h
/*
* cirrus.h 1.4 1999/10/25 20:03:34
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License
* at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
* the License for the specific language governing rights and
* limitations under the License.
*
* The initial developer of the original code is David A. Hinds
* <dahinds@users.sourceforge.net>. Portions created by David A. Hinds
* are Copyright (C) 1999 David A. Hinds. All Rights Reserved.
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License version 2 (the "GPL"), in which
* case the provisions of the GPL are applicable instead of the
* above. If you wish to allow the use of your version of this file
* only under the terms of the GPL and not to allow others to use
* your version of this file under the MPL, indicate your decision by
* deleting the provisions above and replace them with the notice and
* other provisions required by the GPL. If you do not delete the
* provisions above, a recipient may use your version of this file
* under either the MPL or the GPL.
*/
#ifndef _LINUX_CIRRUS_H
#define _LINUX_CIRRUS_H
#ifndef PCI_VENDOR_ID_CIRRUS
#define PCI_VENDOR_ID_CIRRUS 0x1013
#endif
#ifndef PCI_DEVICE_ID_CIRRUS_6729
#define PCI_DEVICE_ID_CIRRUS_6729 0x1100
#endif
#ifndef PCI_DEVICE_ID_CIRRUS_6832
#define PCI_DEVICE_ID_CIRRUS_6832 0x1110
#endif
#define PD67_MISC_CTL_1 0x16 /* Misc control 1 */
#define PD67_FIFO_CTL 0x17 /* FIFO control */
#define PD67_MISC_CTL_2 0x1E /* Misc control 2 */
#define PD67_CHIP_INFO 0x1f /* Chip information */
#define PD67_ATA_CTL 0x026 /* 6730: ATA control */
#define PD67_EXT_INDEX 0x2e /* Extension index */
#define PD67_EXT_DATA 0x2f /* Extension data */
/* PD6722 extension registers -- indexed in PD67_EXT_INDEX */
#define PD67_DATA_MASK0 0x01 /* Data mask 0 */
#define PD67_DATA_MASK1 0x02 /* Data mask 1 */
#define PD67_DMA_CTL 0x03 /* DMA control */
/* PD6730 extension registers -- indexed in PD67_EXT_INDEX */
#define PD67_EXT_CTL_1 0x03 /* Extension control 1 */
#define PD67_MEM_PAGE(n) ((n)+5) /* PCI window bits 31:24 */
#define PD67_EXTERN_DATA 0x0a
#define PD67_MISC_CTL_3 0x25
#define PD67_SMB_PWR_CTL 0x26
/* I/O window address offset */
#define PD67_IO_OFF(w) (0x36+((w)<<1))
/* Timing register sets */
#define PD67_TIME_SETUP(n) (0x3a + 3*(n))
#define PD67_TIME_CMD(n) (0x3b + 3*(n))
#define PD67_TIME_RECOV(n) (0x3c + 3*(n))
/* Flags for PD67_MISC_CTL_1 */
#define PD67_MC1_5V_DET 0x01 /* 5v detect */
#define PD67_MC1_MEDIA_ENA 0x01 /* 6730: Multimedia enable */
#define PD67_MC1_VCC_3V 0x02 /* 3.3v Vcc */
#define PD67_MC1_PULSE_MGMT 0x04
#define PD67_MC1_PULSE_IRQ 0x08
#define PD67_MC1_SPKR_ENA 0x10
#define PD67_MC1_INPACK_ENA 0x80
/* Flags for PD67_FIFO_CTL */
#define PD67_FIFO_EMPTY 0x80
/* Flags for PD67_MISC_CTL_2 */
#define PD67_MC2_FREQ_BYPASS 0x01
#define PD67_MC2_DYNAMIC_MODE 0x02
#define PD67_MC2_SUSPEND 0x04
#define PD67_MC2_5V_CORE 0x08
#define PD67_MC2_LED_ENA 0x10 /* IRQ 12 is LED enable */
#define PD67_MC2_FAST_PCI 0x10 /* 6729: PCI bus > 25 MHz */
#define PD67_MC2_3STATE_BIT7 0x20 /* Floppy change bit */
#define PD67_MC2_DMA_MODE 0x40
#define PD67_MC2_IRQ15_RI 0x80 /* IRQ 15 is ring enable */
/* Flags for PD67_CHIP_INFO */
#define PD67_INFO_SLOTS 0x20 /* 0 = 1 slot, 1 = 2 slots */
#define PD67_INFO_CHIP_ID 0xc0
#define PD67_INFO_REV 0x1c
/* Fields in PD67_TIME_* registers */
#define PD67_TIME_SCALE 0xc0
#define PD67_TIME_SCALE_1 0x00
#define PD67_TIME_SCALE_16 0x40
#define PD67_TIME_SCALE_256 0x80
#define PD67_TIME_SCALE_4096 0xc0
#define PD67_TIME_MULT 0x3f
/* Fields in PD67_DMA_CTL */
#define PD67_DMA_MODE 0xc0
#define PD67_DMA_OFF 0x00
#define PD67_DMA_DREQ_INPACK 0x40
#define PD67_DMA_DREQ_WP 0x80
#define PD67_DMA_DREQ_BVD2 0xc0
#define PD67_DMA_PULLUP 0x20 /* Disable socket pullups? */
/* Fields in PD67_EXT_CTL_1 */
#define PD67_EC1_VCC_PWR_LOCK 0x01
#define PD67_EC1_AUTO_PWR_CLEAR 0x02
#define PD67_EC1_LED_ENA 0x04
#define PD67_EC1_INV_CARD_IRQ 0x08
#define PD67_EC1_INV_MGMT_IRQ 0x10
#define PD67_EC1_PULLUP_CTL 0x20
/* Fields in PD67_MISC_CTL_3 */
#define PD67_MC3_IRQ_MASK 0x03
#define PD67_MC3_IRQ_PCPCI 0x00
#define PD67_MC3_IRQ_EXTERN 0x01
#define PD67_MC3_IRQ_PCIWAY 0x02
#define PD67_MC3_IRQ_PCI 0x03
#define PD67_MC3_PWR_MASK 0x0c
#define PD67_MC3_PWR_SERIAL 0x00
#define PD67_MC3_PWR_TI2202 0x08
#define PD67_MC3_PWR_SMB 0x0c
/* Register definitions for Cirrus PD6832 PCI-to-CardBus bridge */
/* PD6832 extension registers -- indexed in PD67_EXT_INDEX */
#define PD68_EXT_CTL_2 0x0b
#define PD68_PCI_SPACE 0x22
#define PD68_PCCARD_SPACE 0x23
#define PD68_WINDOW_TYPE 0x24
#define PD68_EXT_CSC 0x2e
#define PD68_MISC_CTL_4 0x2f
#define PD68_MISC_CTL_5 0x30
#define PD68_MISC_CTL_6 0x31
/* Extra flags in PD67_MISC_CTL_3 */
#define PD68_MC3_HW_SUSP 0x10
#define PD68_MC3_MM_EXPAND 0x40
#define PD68_MC3_MM_ARM 0x80
/* Bridge Control Register */
#define PD6832_BCR_MGMT_IRQ_ENA 0x0800
/* Socket Number Register */
#define PD6832_SOCKET_NUMBER 0x004c /* 8 bit */
#endif /* _LINUX_CIRRUS_H */
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