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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yenta_socket.h
#ifndef __YENTA_H
#define __YENTA_H
#include <asm/io.h>
#define CB_SOCKET_EVENT 0x00
#define CB_CSTSEVENT 0x00000001 /* Card status event */
#define CB_CD1EVENT 0x00000002 /* Card detect 1 change event */
#define CB_CD2EVENT 0x00000004 /* Card detect 2 change event */
#define CB_PWREVENT 0x00000008 /* PWRCYCLE change event */
#define CB_SOCKET_MASK 0x04
#define CB_CSTSMASK 0x00000001 /* Card status mask */
#define CB_CDMASK 0x00000006 /* Card detect 1&2 mask */
#define CB_PWRMASK 0x00000008 /* PWRCYCLE change mask */
#define CB_SOCKET_STATE 0x08
#define CB_CARDSTS 0x00000001 /* CSTSCHG status */
#define CB_CDETECT1 0x00000002 /* Card detect status 1 */
#define CB_CDETECT2 0x00000004 /* Card detect status 2 */
#define CB_PWRCYCLE 0x00000008 /* Socket powered */
#define CB_16BITCARD 0x00000010 /* 16-bit card detected */
#define CB_CBCARD 0x00000020 /* CardBus card detected */
#define CB_IREQCINT 0x00000040 /* READY(xIRQ)/xCINT high */
#define CB_NOTACARD 0x00000080 /* Unrecognizable PC card detected */
#define CB_DATALOST 0x00000100 /* Potential data loss due to card removal */
#define CB_BADVCCREQ 0x00000200 /* Invalid Vcc request by host software */
#define CB_5VCARD 0x00000400 /* Card Vcc at 5.0 volts? */
#define CB_3VCARD 0x00000800 /* Card Vcc at 3.3 volts? */
#define CB_XVCARD 0x00001000 /* Card Vcc at X.X volts? */
#define CB_YVCARD 0x00002000 /* Card Vcc at Y.Y volts? */
#define CB_5VSOCKET 0x10000000 /* Socket Vcc at 5.0 volts? */
#define CB_3VSOCKET 0x20000000 /* Socket Vcc at 3.3 volts? */
#define CB_XVSOCKET 0x40000000 /* Socket Vcc at X.X volts? */
#define CB_YVSOCKET 0x80000000 /* Socket Vcc at Y.Y volts? */
#define CB_SOCKET_FORCE 0x0C
#define CB_FCARDSTS 0x00000001 /* Force CSTSCHG */
#define CB_FCDETECT1 0x00000002 /* Force CD1EVENT */
#define CB_FCDETECT2 0x00000004 /* Force CD2EVENT */
#define CB_FPWRCYCLE 0x00000008 /* Force PWREVENT */
#define CB_F16BITCARD 0x00000010 /* Force 16-bit PCMCIA card */
#define CB_FCBCARD 0x00000020 /* Force CardBus line */
#define CB_FNOTACARD 0x00000080 /* Force NOTACARD */
#define CB_FDATALOST 0x00000100 /* Force data lost */
#define CB_FBADVCCREQ 0x00000200 /* Force bad Vcc request */
#define CB_F5VCARD 0x00000400 /* Force 5.0 volt card */
#define CB_F3VCARD 0x00000800 /* Force 3.3 volt card */
#define CB_FXVCARD 0x00001000 /* Force X.X volt card */
#define CB_FYVCARD 0x00002000 /* Force Y.Y volt card */
#define CB_CVSTEST 0x00004000 /* Card VS test */
#define CB_SOCKET_CONTROL 0x10
#define CB_SC_VPP_MASK 0x00000007
#define CB_SC_VPP_OFF 0x00000000
#define CB_SC_VPP_12V 0x00000001
#define CB_SC_VPP_5V 0x00000002
#define CB_SC_VPP_3V 0x00000003
#define CB_SC_VPP_XV 0x00000004
#define CB_SC_VPP_YV 0x00000005
#define CB_SC_VCC_MASK 0x00000070
#define CB_SC_VCC_OFF 0x00000000
#define CB_SC_VCC_5V 0x00000020
#define CB_SC_VCC_3V 0x00000030
#define CB_SC_VCC_XV 0x00000040
#define CB_SC_VCC_YV 0x00000050
#define CB_SC_CCLK_STOP 0x00000080
#define CB_SOCKET_POWER 0x20
#define CB_SKTACCES 0x02000000 /* A PC card access has occurred (clear on read) */
#define CB_SKTMODE 0x01000000 /* Clock frequency has changed (clear on read) */
#define CB_CLKCTRLEN 0x00010000 /* Clock control enabled (RW) */
#define CB_CLKCTRL 0x00000001 /* Stop(0) or slow(1) CB clock (RW) */
/*
* Cardbus configuration space
*/
#define CB_BRIDGE_BASE(m) (0x1c + 8*(m))
#define CB_BRIDGE_LIMIT(m) (0x20 + 8*(m))
#define CB_BRIDGE_CONTROL 0x3e
#define CB_BRIDGE_CPERREN 0x00000001
#define CB_BRIDGE_CSERREN 0x00000002
#define CB_BRIDGE_ISAEN 0x00000004
#define CB_BRIDGE_VGAEN 0x00000008
#define CB_BRIDGE_MABTMODE 0x00000020
#define CB_BRIDGE_CRST 0x00000040
#define CB_BRIDGE_INTR 0x00000080
#define CB_BRIDGE_PREFETCH0 0x00000100
#define CB_BRIDGE_PREFETCH1 0x00000200
#define CB_BRIDGE_POSTEN 0x00000400
#define CB_LEGACY_MODE_BASE 0x44
/*
* ExCA area extensions in Yenta
*/
#define CB_MEM_PAGE(map) (0x40 + (map))
/* control how 16bit cards are powered */
#define YENTA_16BIT_POWER_EXCA 0x00000001
#define YENTA_16BIT_POWER_DF 0x00000002
struct yenta_socket;
struct cardbus_type {
int (*override)(struct yenta_socket *);
void (*save_state)(struct yenta_socket *);
void (*restore_state)(struct yenta_socket *);
int (*sock_init)(struct yenta_socket *);
};
struct yenta_socket {
struct pci_dev *dev;
int cb_irq, io_irq;
void __iomem *base;
struct timer_list poll_timer;
struct pcmcia_socket socket;
struct cardbus_type *type;
u32 flags;
/* for PCI interrupt probing */
unsigned int probe_status;
/* A few words of private data for special stuff of overrides... */
unsigned int private[8];
/* PCI saved state */
u32 saved_state[2];
};
#endif
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