2.6.4-rc1-mm1: queue-congestion-dm-implementation patch

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* 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch
@ 2004-03-01 20:00 ` Kevin Corry
  2004-03-02 13:01   ` Miquel van Smoorenburg
  0 siblings, 1 reply; 5+ messages in thread
From: Kevin Corry @ 2004-03-01 20:00 UTC (permalink / raw)
  To: DevMapper, LKML

The queue-congestion-dm-implementation patch in 2.6.4-rc1-mm1 (included below) 
allows a DM device to query the lower-level device(s) during the 
queue-congestion APIs. However, it must wait on an internal semaphore 
(md->lock) before passing the call down to the lower-level devices. The 
problem is that the higher-level caller is holding a spinlock at the same 
time. Here is one such stack-trace I have been seeing:

Debug: sleeping function called from invalid context at include/linux/
rwsem.h:43
in_atomic():1, irqs_disabled():0
Call Trace:
 [<c012456b>] __might_sleep+0xab/0xd0
 [<c03a0771>] dm_any_congested+0x21/0x60
 [<c0192a82>] sync_sb_inodes+0x2d2/0x2f0
 [<c0192b4c>] writeback_inodes+0xac/0x1d0
 [<c014c68b>] wb_kupdate+0xdb/0x170
 [<c014cf49>] __pdflush+0x1b9/0x380
 [<c014d121>] pdflush+0x11/0x20
 [<c014c5b0>] wb_kupdate+0x0/0x170
 [<c013f6b6>] kthread+0xb6/0xc0
 [<c014d110>] pdflush+0x0/0x20
 [<c013f600>] kthread+0x0/0xc0
 [<c01070cd>] kernel_thread_helper+0x5/0x18

I'm not sure how to fix this (or how serious a problem it is)...I'm just 
throwing this out there for discussion.

-- 
Kevin Corry
kevcorry@us.ibm.com
http://evms.sourceforge.net/




--- diff/drivers/md/dm-table.c	2004-03-01 14:36:06.000000000 +0000
+++ source/drivers/md/dm-table.c	2004-03-01 15:42:16.000000000 +0000
@@ -862,6 +862,20 @@ void dm_table_resume_targets(struct dm_t
 	}
 }
 
+int dm_table_any_congested(struct dm_table *t, int bdi_bits)
+{
+	struct list_head *d, *devices;
+	int r = 0;
+
+	devices = dm_table_get_devices(t);
+	for (d = devices->next; d != devices; d = d->next) {
+		struct dm_dev *dd = list_entry(d, struct dm_dev, list);
+		request_queue_t *q = bdev_get_queue(dd->bdev);
+		r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+	}
+
+	return r;
+}
 
 EXPORT_SYMBOL(dm_vcalloc);
 EXPORT_SYMBOL(dm_get_device);
--- diff/drivers/md/dm.c	2004-03-01 14:36:06.000000000 +0000
+++ source/drivers/md/dm.c	2004-03-01 15:42:16.000000000 +0000
@@ -489,6 +489,18 @@ static int dm_request(request_queue_t *q
 	return 0;
 }
 
+static int dm_any_congested(void *congested_data, int bdi_bits)
+{
+	int r;
+	struct mapped_device *md = congested_data;
+
+	down_read(&md->lock);
+	r = dm_table_any_congested(md->map, bdi_bits);
+	up_read(&md->lock);
+
+	return r;
+}
+
 /*-----------------------------------------------------------------
  * A bitset is used to keep track of allocated minor numbers.
  *---------------------------------------------------------------*/
@@ -567,6 +579,8 @@ static struct mapped_device *alloc_dev(u
 		goto bad1;
 
 	md->queue->queuedata = md;
+	md->queue->backing_dev_info.congested_fn = dm_any_congested;
+	md->queue->backing_dev_info.congested_data = md;
 	blk_queue_make_request(md->queue, dm_request);
 
 	md->io_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
--- diff/drivers/md/dm.h	2004-03-01 14:36:06.000000000 +0000
+++ source/drivers/md/dm.h	2004-03-01 15:42:16.000000000 +0000
@@ -115,6 +115,7 @@ struct list_head *dm_table_get_devices(s
 int dm_table_get_mode(struct dm_table *t);
 void dm_table_suspend_targets(struct dm_table *t);
 void dm_table_resume_targets(struct dm_table *t);
+int dm_table_any_congested(struct dm_table *t, int bdi_bits);
 
 /*-----------------------------------------------------------------
  * A registry of target types.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch
  2004-03-01 20:00 ` 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch Kevin Corry
@ 2004-03-02 13:01   ` Miquel van Smoorenburg
  2004-03-02 14:26     ` Kevin Corry
  0 siblings, 1 reply; 5+ messages in thread
From: Miquel van Smoorenburg @ 2004-03-02 13:01 UTC (permalink / raw)
  To: Kevin Corry; +Cc: linux-kernel

According to Kevin Corry:
> Article: 452202 of lists.linux.kernel
> From: Kevin Corry <kevcorry@us.ibm.com>
> Date:	Mon, 1 Mar 2004 14:00:50 -0600
> Newsgroups: lists.linux.kernel
> Approved: news@news.cistron.nl
> 
> The queue-congestion-dm-implementation patch in 2.6.4-rc1-mm1 (included below) 
> allows a DM device to query the lower-level device(s) during the 
> queue-congestion APIs. However, it must wait on an internal semaphore 
> (md->lock) before passing the call down to the lower-level devices. The 
> problem is that the higher-level caller is holding a spinlock at the same 
> time. Here is one such stack-trace I have been seeing:
> 
> Debug: sleeping function called from invalid context at include/linux/
> rwsem.h:43
> in_atomic():1, irqs_disabled():0
> Call Trace:
>  [<c012456b>] __might_sleep+0xab/0xd0
>  [<c03a0771>] dm_any_congested+0x21/0x60

Is there any way to reproduce this? I turned on spinlock and
sleep-spinlock debugging and did lots of I/O but I don't see it.

> I'm not sure how to fix this (or how serious a problem it is)...I'm just 
> throwing this out there for discussion.

Well bdi_write_congested() is racy, ofcourse, so in theory a call
to make_request() could be made which can block (and for dm, locks
the same semaphore) - so this can happen anyway. Only the chance of
it is much lower. I'm not sure how bad it is.

Changing down_read() in dm_any_congested to down_read_trylock() would
probably fix it for bdi_*_congested(). If you can tell me how to
reproduce it I can try a few things..

Mike.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch
  2004-03-02 13:01   ` Miquel van Smoorenburg
@ 2004-03-02 14:26     ` Kevin Corry
  2004-03-02 22:21       ` Andrew Morton
  0 siblings, 1 reply; 5+ messages in thread
From: Kevin Corry @ 2004-03-02 14:26 UTC (permalink / raw)
  To: linux-kernel; +Cc: Miquel van Smoorenburg

On Tuesday 02 March 2004 7:01 am, Miquel van Smoorenburg wrote:
> According to Kevin Corry:
> > The queue-congestion-dm-implementation patch in 2.6.4-rc1-mm1 (included
> > below) allows a DM device to query the lower-level device(s) during the
> > queue-congestion APIs. However, it must wait on an internal semaphore
> > (md->lock) before passing the call down to the lower-level devices. The
> > problem is that the higher-level caller is holding a spinlock at the same
> > time. Here is one such stack-trace I have been seeing:
> >
> > Debug: sleeping function called from invalid context at include/linux/
> > rwsem.h:43
> > in_atomic():1, irqs_disabled():0
> > Call Trace:
> >  [<c012456b>] __might_sleep+0xab/0xd0
> >  [<c03a0771>] dm_any_congested+0x21/0x60
>
> Is there any way to reproduce this? I turned on spinlock and
> sleep-spinlock debugging and did lots of I/O but I don't see it.

I didn't really do anything special to hit this. I had a linear device-mapper 
device (created with EVMS, but LVM2 can do the same thing) with Reiserfs. Any 
I/O to the device produced a constant stream of these warnings in syslog. 
I've retried with ext3, xfs, and jfs and have the same problem. My kernel 
config is included below. Perhaps worth noting that I'm running with SMP and 
PREEMPT enabled, even though I'm on a UP box.

> > I'm not sure how to fix this (or how serious a problem it is)...I'm just
> > throwing this out there for discussion.
>
> Well bdi_write_congested() is racy, ofcourse, so in theory a call
> to make_request() could be made which can block (and for dm, locks
> the same semaphore) - so this can happen anyway. Only the chance of
> it is much lower. I'm not sure how bad it is.

The DM lock is only a read-lock in both dm_any_congested() and dm_request(). 
This lock only exists to make sure someone doesn't modify the device (e.g. 
suspend the device, load a new table) while the device is being accessed 
(e.g. for I/O).

But...I'm not entirely sure I understand you're reasoning here, so there might 
be something I'm missing. After all, I don't yet fully understand the purpose 
behind the bdi_*_congested() code....I'm simply reporting a potential 
problem.

> Changing down_read() in dm_any_congested to down_read_trylock() would
> probably fix it for bdi_*_congested(). If you can tell me how to
> reproduce it I can try a few things..

Switching to down_read_trylock() would certainly eliminate this problem, as 
long as you don't *need* to check the congestion of the underlying devices 
each time dm_any_congested() is called.

Sorry I can't tell you how exactly to reproduce this. :(  I'm not doing 
anything at all out-of-the-ordinary.

-- 
Kevin Corry
kevcorry@us.ibm.com
http://evms.sourceforge.net/


#
# Automatically generated make config: don't edit
#
CONFIG_X86=y
CONFIG_MMU=y
CONFIG_UID16=y
CONFIG_GENERIC_ISA_DMA=y

#
# Code maturity level options
#
CONFIG_EXPERIMENTAL=y
CONFIG_CLEAN_COMPILE=y
CONFIG_STANDALONE=y

#
# General setup
#
CONFIG_SWAP=y
CONFIG_SYSVIPC=y
# CONFIG_POSIX_MQUEUE is not set
# CONFIG_BSD_PROCESS_ACCT is not set
CONFIG_SYSCTL=y
CONFIG_LOG_BUF_SHIFT=16
CONFIG_HOTPLUG=y
# CONFIG_IKCONFIG is not set
# CONFIG_EMBEDDED is not set
CONFIG_KALLSYMS=y
CONFIG_FUTEX=y
CONFIG_EPOLL=y
CONFIG_IOSCHED_NOOP=y
CONFIG_IOSCHED_AS=y
CONFIG_IOSCHED_DEADLINE=y
CONFIG_IOSCHED_CFQ=y
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set

#
# Loadable module support
#
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_FORCE_UNLOAD=y
CONFIG_OBSOLETE_MODPARM=y
# CONFIG_MODVERSIONS is not set
CONFIG_KMOD=y
CONFIG_STOP_MACHINE=y

#
# Processor type and features
#
CONFIG_X86_PC=y
# CONFIG_X86_ELAN is not set
# CONFIG_X86_VOYAGER is not set
# CONFIG_X86_NUMAQ is not set
# CONFIG_X86_SUMMIT is not set
# CONFIG_X86_BIGSMP is not set
# CONFIG_X86_VISWS is not set
# CONFIG_X86_GENERICARCH is not set
# CONFIG_X86_ES7000 is not set
# CONFIG_M386 is not set
# CONFIG_M486 is not set
# CONFIG_M586 is not set
# CONFIG_M586TSC is not set
# CONFIG_M586MMX is not set
# CONFIG_M686 is not set
CONFIG_MPENTIUMII=y
# CONFIG_MPENTIUMIII is not set
# CONFIG_MPENTIUMM is not set
# CONFIG_MPENTIUM4 is not set
# CONFIG_MK6 is not set
# CONFIG_MK7 is not set
# CONFIG_MK8 is not set
# CONFIG_MELAN is not set
# CONFIG_MCRUSOE is not set
# CONFIG_MWINCHIPC6 is not set
# CONFIG_MWINCHIP2 is not set
# CONFIG_MWINCHIP3D is not set
# CONFIG_MCYRIXIII is not set
# CONFIG_MVIAC3_2 is not set
# CONFIG_X86_GENERIC is not set
CONFIG_X86_CMPXCHG=y
CONFIG_X86_XADD=y
CONFIG_X86_L1_CACHE_SHIFT=5
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_X86_WP_WORKS_OK=y
CONFIG_X86_INVLPG=y
CONFIG_X86_BSWAP=y
CONFIG_X86_POPAD_OK=y
CONFIG_X86_GOOD_APIC=y
CONFIG_X86_INTEL_USERCOPY=y
CONFIG_X86_USE_PPRO_CHECKSUM=y
# CONFIG_X86_4G is not set
# CONFIG_X86_SWITCH_PAGETABLES is not set
# CONFIG_X86_4G_VM_LAYOUT is not set
# CONFIG_X86_UACCESS_INDIRECT is not set
# CONFIG_X86_HIGH_ENTRY is not set
# CONFIG_HPET_TIMER is not set
# CONFIG_HPET_EMULATE_RTC is not set
CONFIG_SMP=y
CONFIG_NR_CPUS=4
# CONFIG_SCHED_SMT is not set
CONFIG_PREEMPT=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_IO_APIC=y
CONFIG_X86_TSC=y
CONFIG_X86_MCE=y
# CONFIG_X86_MCE_NONFATAL is not set
# CONFIG_X86_MCE_P4THERMAL is not set
# CONFIG_TOSHIBA is not set
# CONFIG_I8K is not set
# CONFIG_MICROCODE is not set
# CONFIG_X86_MSR is not set
# CONFIG_X86_CPUID is not set
# CONFIG_EDD is not set
CONFIG_NOHIGHMEM=y
# CONFIG_HIGHMEM4G is not set
# CONFIG_HIGHMEM64G is not set
# CONFIG_MATH_EMULATION is not set
CONFIG_MTRR=y
CONFIG_IRQBALANCE=y
CONFIG_HAVE_DEC_LOCK=y
# CONFIG_REGPARM is not set

#
# Power management options (ACPI, APM)
#
# CONFIG_PM is not set

#
# ACPI (Advanced Configuration and Power Interface) Support
#
# CONFIG_ACPI is not set
CONFIG_ACPI_BOOT=y

#
# CPU Frequency scaling
#
# CONFIG_CPU_FREQ is not set

#
# Bus options (PCI, PCMCIA, EISA, MCA, ISA)
#
CONFIG_PCI=y
# CONFIG_PCI_GOBIOS is not set
# CONFIG_PCI_GOMMCONFIG is not set
# CONFIG_PCI_GODIRECT is not set
CONFIG_PCI_GOANY=y
CONFIG_PCI_BIOS=y
CONFIG_PCI_DIRECT=y
CONFIG_PCI_MMCONFIG=y
# CONFIG_PCI_USE_VECTOR is not set
CONFIG_PCI_LEGACY_PROC=y
CONFIG_PCI_NAMES=y
CONFIG_ISA=y
# CONFIG_EISA is not set
# CONFIG_MCA is not set
# CONFIG_SCx200 is not set

#
# PCMCIA/CardBus support
#
# CONFIG_PCMCIA is not set
CONFIG_PCMCIA_PROBE=y

#
# PCI Hotplug Support
#
CONFIG_HOTPLUG_PCI=y
# CONFIG_HOTPLUG_PCI_FAKE is not set
# CONFIG_HOTPLUG_PCI_COMPAQ is not set
# CONFIG_HOTPLUG_PCI_IBM is not set
# CONFIG_HOTPLUG_PCI_CPCI is not set
# CONFIG_HOTPLUG_PCI_PCIE is not set
# CONFIG_HOTPLUG_PCI_SHPC is not set

#
# Executable file formats
#
CONFIG_BINFMT_ELF=y
CONFIG_BINFMT_AOUT=y
CONFIG_BINFMT_MISC=y

#
# Device Drivers
#

#
# Generic Driver Options
#
# CONFIG_FW_LOADER is not set

#
# Memory Technology Devices (MTD)
#
# CONFIG_MTD is not set

#
# Parallel port support
#
# CONFIG_PARPORT is not set

#
# Plug and Play support
#
CONFIG_PNP=y
# CONFIG_PNP_DEBUG is not set

#
# Protocols
#
# CONFIG_ISAPNP is not set
# CONFIG_PNPBIOS is not set

#
# Block devices
#
CONFIG_BLK_DEV_FD=y
# CONFIG_BLK_DEV_XD is not set
# CONFIG_BLK_CPQ_DA is not set
# CONFIG_BLK_CPQ_CISS_DA is not set
# CONFIG_BLK_DEV_DAC960 is not set
# CONFIG_BLK_DEV_UMEM is not set
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_CRYPTOLOOP=m
CONFIG_BLK_DEV_NBD=m
CONFIG_BLK_DEV_RAM=y
CONFIG_BLK_DEV_RAM_SIZE=16384
CONFIG_BLK_DEV_INITRD=y
CONFIG_LBD=y

#
# ATA/ATAPI/MFM/RLL support
#
CONFIG_IDE=y
CONFIG_BLK_DEV_IDE=y

#
# Please see Documentation/ide.txt for help/info on IDE drives
#
# CONFIG_BLK_DEV_HD_IDE is not set
CONFIG_BLK_DEV_IDEDISK=y
# CONFIG_IDEDISK_MULTI_MODE is not set
# CONFIG_IDEDISK_STROKE is not set
CONFIG_BLK_DEV_IDECD=y
# CONFIG_BLK_DEV_IDETAPE is not set
# CONFIG_BLK_DEV_IDEFLOPPY is not set
# CONFIG_BLK_DEV_IDESCSI is not set
# CONFIG_IDE_TASK_IOCTL is not set
CONFIG_IDE_TASKFILE_IO=y

#
# IDE chipset support/bugfixes
#
CONFIG_IDE_GENERIC=y
CONFIG_BLK_DEV_CMD640=y
# CONFIG_BLK_DEV_CMD640_ENHANCED is not set
# CONFIG_BLK_DEV_IDEPNP is not set
CONFIG_BLK_DEV_IDEPCI=y
CONFIG_IDEPCI_SHARE_IRQ=y
# CONFIG_BLK_DEV_OFFBOARD is not set
CONFIG_BLK_DEV_GENERIC=y
# CONFIG_BLK_DEV_OPTI621 is not set
CONFIG_BLK_DEV_RZ1000=y
CONFIG_BLK_DEV_IDEDMA_PCI=y
# CONFIG_BLK_DEV_IDEDMA_FORCED is not set
CONFIG_IDEDMA_PCI_AUTO=y
# CONFIG_IDEDMA_ONLYDISK is not set
CONFIG_BLK_DEV_ADMA=y
# CONFIG_BLK_DEV_AEC62XX is not set
# CONFIG_BLK_DEV_ALI15X3 is not set
# CONFIG_BLK_DEV_AMD74XX is not set
# CONFIG_BLK_DEV_CMD64X is not set
# CONFIG_BLK_DEV_TRIFLEX is not set
# CONFIG_BLK_DEV_CY82C693 is not set
# CONFIG_BLK_DEV_CS5520 is not set
# CONFIG_BLK_DEV_CS5530 is not set
# CONFIG_BLK_DEV_HPT34X is not set
# CONFIG_BLK_DEV_HPT366 is not set
# CONFIG_BLK_DEV_SC1200 is not set
CONFIG_BLK_DEV_PIIX=y
# CONFIG_BLK_DEV_NS87415 is not set
# CONFIG_BLK_DEV_PDC202XX_OLD is not set
# CONFIG_BLK_DEV_PDC202XX_NEW is not set
# CONFIG_BLK_DEV_SVWKS is not set
# CONFIG_BLK_DEV_SIIMAGE is not set
# CONFIG_BLK_DEV_SIS5513 is not set
# CONFIG_BLK_DEV_SLC90E66 is not set
# CONFIG_BLK_DEV_TRM290 is not set
# CONFIG_BLK_DEV_VIA82CXXX is not set
# CONFIG_IDE_CHIPSETS is not set
CONFIG_BLK_DEV_IDEDMA=y
# CONFIG_IDEDMA_IVB is not set
CONFIG_IDEDMA_AUTO=y
# CONFIG_DMA_NONPCI is not set
# CONFIG_BLK_DEV_HD is not set

#
# SCSI device support
#
CONFIG_SCSI=y
CONFIG_SCSI_PROC_FS=y

#
# SCSI support type (disk, tape, CD-ROM)
#
CONFIG_BLK_DEV_SD=y
CONFIG_MAX_SD_DISKS=256
# CONFIG_CHR_DEV_ST is not set
# CONFIG_CHR_DEV_OSST is not set
# CONFIG_BLK_DEV_SR is not set
# CONFIG_CHR_DEV_SG is not set

#
# Some SCSI devices (e.g. CD jukebox) support multiple LUNs
#
# CONFIG_SCSI_MULTI_LUN is not set
# CONFIG_SCSI_REPORT_LUNS is not set
CONFIG_SCSI_CONSTANTS=y
# CONFIG_SCSI_LOGGING is not set

#
# SCSI low-level drivers
#
# CONFIG_BLK_DEV_3W_XXXX_RAID is not set
# CONFIG_SCSI_7000FASST is not set
# CONFIG_SCSI_ACARD is not set
# CONFIG_SCSI_AHA152X is not set
# CONFIG_SCSI_AHA1542 is not set
# CONFIG_SCSI_AACRAID is not set
CONFIG_SCSI_AIC7XXX=y
CONFIG_AIC7XXX_CMDS_PER_DEVICE=32
CONFIG_AIC7XXX_RESET_DELAY_MS=15000
# CONFIG_AIC7XXX_BUILD_FIRMWARE is not set
CONFIG_AIC7XXX_DEBUG_ENABLE=y
CONFIG_AIC7XXX_DEBUG_MASK=0
CONFIG_AIC7XXX_REG_PRETTY_PRINT=y
# CONFIG_SCSI_AIC7XXX_OLD is not set
# CONFIG_SCSI_AIC79XX is not set
# CONFIG_SCSI_ADVANSYS is not set
# CONFIG_SCSI_IN2000 is not set
# CONFIG_SCSI_MEGARAID is not set
# CONFIG_SCSI_SATA is not set
# CONFIG_SCSI_BUSLOGIC is not set
# CONFIG_SCSI_CPQFCTS is not set
# CONFIG_SCSI_DMX3191D is not set
# CONFIG_SCSI_DTC3280 is not set
# CONFIG_SCSI_EATA is not set
# CONFIG_SCSI_EATA_PIO is not set
# CONFIG_SCSI_FUTURE_DOMAIN is not set
# CONFIG_SCSI_GDTH is not set
# CONFIG_SCSI_GENERIC_NCR5380 is not set
# CONFIG_SCSI_GENERIC_NCR5380_MMIO is not set
# CONFIG_SCSI_IPS is not set
# CONFIG_SCSI_INIA100 is not set
# CONFIG_SCSI_NCR53C406A is not set
# CONFIG_SCSI_SYM53C8XX_2 is not set
# CONFIG_SCSI_PAS16 is not set
# CONFIG_SCSI_PSI240I is not set
# CONFIG_SCSI_QLOGIC_FAS is not set
# CONFIG_SCSI_QLOGIC_ISP is not set
# CONFIG_SCSI_QLOGIC_FC is not set
# CONFIG_SCSI_QLOGIC_1280 is not set
CONFIG_SCSI_QLA2XXX=y
# CONFIG_SCSI_QLA21XX is not set
# CONFIG_SCSI_QLA22XX is not set
# CONFIG_SCSI_QLA2300 is not set
# CONFIG_SCSI_QLA2322 is not set
# CONFIG_SCSI_QLA6312 is not set
# CONFIG_SCSI_QLA6322 is not set
# CONFIG_SCSI_SYM53C416 is not set
# CONFIG_SCSI_DC395x is not set
# CONFIG_SCSI_DC390T is not set
# CONFIG_SCSI_T128 is not set
# CONFIG_SCSI_U14_34F is not set
# CONFIG_SCSI_ULTRASTOR is not set
# CONFIG_SCSI_NSP32 is not set
# CONFIG_SCSI_DEBUG is not set

#
# Old CD-ROM drivers (not SCSI, not IDE)
#
# CONFIG_CD_NO_IDESCSI is not set

#
# Multi-device support (RAID and LVM)
#
CONFIG_MD=y
CONFIG_BLK_DEV_MD=y
CONFIG_MD_LINEAR=y
CONFIG_MD_RAID0=y
CONFIG_MD_RAID1=y
CONFIG_MD_RAID5=y
CONFIG_MD_RAID6=y
CONFIG_MD_MULTIPATH=y
CONFIG_BLK_DEV_DM=y
CONFIG_DM_CRYPT=y
CONFIG_DM_MULTIPATH=y
CONFIG_DM_SNAPSHOT=y
CONFIG_DM_MIRROR=y
CONFIG_DM_FLAKEY=y
CONFIG_BLK_DEV_DM_BBR=y

#
# Fusion MPT device support
#
# CONFIG_FUSION is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_IEEE1394 is not set

#
# I2O device support
#
# CONFIG_I2O is not set

#
# Macintosh device drivers
#

#
# Networking support
#
CONFIG_NET=y

#
# Networking options
#
CONFIG_PACKET=y
# CONFIG_PACKET_MMAP is not set
# CONFIG_NETLINK_DEV is not set
CONFIG_UNIX=y
CONFIG_NET_KEY=y
CONFIG_INET=y
# CONFIG_IP_MULTICAST is not set
# CONFIG_IP_ADVANCED_ROUTER is not set
# CONFIG_IP_PNP is not set
# CONFIG_NET_IPIP is not set
# CONFIG_NET_IPGRE is not set
# CONFIG_ARPD is not set
# CONFIG_INET_ECN is not set
# CONFIG_SYN_COOKIES is not set
# CONFIG_INET_AH is not set
# CONFIG_INET_ESP is not set
# CONFIG_INET_IPCOMP is not set
# CONFIG_IPV6 is not set
# CONFIG_DECNET is not set
# CONFIG_BRIDGE is not set
# CONFIG_NETFILTER is not set
CONFIG_XFRM=y
# CONFIG_XFRM_USER is not set

#
# SCTP Configuration (EXPERIMENTAL)
#
CONFIG_IPV6_SCTP__=y
# CONFIG_IP_SCTP is not set
# CONFIG_ATM is not set
# CONFIG_VLAN_8021Q is not set
# CONFIG_LLC2 is not set
# CONFIG_IPX is not set
# CONFIG_ATALK is not set
# CONFIG_X25 is not set
# CONFIG_LAPB is not set
# CONFIG_NET_DIVERT is not set
# CONFIG_ECONET is not set
# CONFIG_WAN_ROUTER is not set
# CONFIG_NET_FASTROUTE is not set
# CONFIG_NET_HW_FLOWCONTROL is not set

#
# QoS and/or fair queueing
#
# CONFIG_NET_SCHED is not set

#
# Network testing
#
# CONFIG_NET_PKTGEN is not set
CONFIG_NETDEVICES=y

#
# ARCnet devices
#
# CONFIG_ARCNET is not set
# CONFIG_DUMMY is not set
# CONFIG_BONDING is not set
# CONFIG_EQUALIZER is not set
# CONFIG_TUN is not set
# CONFIG_NET_SB1000 is not set

#
# Ethernet (10 or 100Mbit)
#
CONFIG_NET_ETHERNET=y
CONFIG_MII=y
# CONFIG_HAPPYMEAL is not set
# CONFIG_SUNGEM is not set
# CONFIG_NET_VENDOR_3COM is not set
# CONFIG_LANCE is not set
# CONFIG_NET_VENDOR_SMC is not set
# CONFIG_NET_VENDOR_RACAL is not set

#
# Tulip family network device support
#
# CONFIG_NET_TULIP is not set
# CONFIG_AT1700 is not set
# CONFIG_DEPCA is not set
# CONFIG_HP100 is not set
# CONFIG_NET_ISA is not set
CONFIG_NET_PCI=y
# CONFIG_PCNET32 is not set
# CONFIG_AMD8111_ETH is not set
# CONFIG_ADAPTEC_STARFIRE is not set
# CONFIG_AC3200 is not set
# CONFIG_APRICOT is not set
# CONFIG_B44 is not set
# CONFIG_FORCEDETH is not set
# CONFIG_CS89x0 is not set
# CONFIG_DGRS is not set
# CONFIG_EEPRO100 is not set
CONFIG_E100=y
# CONFIG_E100_NAPI is not set
# CONFIG_FEALNX is not set
# CONFIG_NATSEMI is not set
# CONFIG_NE2K_PCI is not set
# CONFIG_8139CP is not set
# CONFIG_8139TOO is not set
# CONFIG_SIS900 is not set
# CONFIG_EPIC100 is not set
# CONFIG_SUNDANCE is not set
# CONFIG_TLAN is not set
# CONFIG_VIA_RHINE is not set
# CONFIG_NET_POCKET is not set

#
# Ethernet (1000 Mbit)
#
# CONFIG_ACENIC is not set
# CONFIG_DL2K is not set
# CONFIG_E1000 is not set
# CONFIG_NS83820 is not set
# CONFIG_HAMACHI is not set
# CONFIG_YELLOWFIN is not set
# CONFIG_R8169 is not set
# CONFIG_SIS190 is not set
# CONFIG_SK98LIN is not set
# CONFIG_TIGON3 is not set

#
# Ethernet (10000 Mbit)
#
# CONFIG_IXGB is not set
# CONFIG_FDDI is not set
# CONFIG_HIPPI is not set
# CONFIG_PPP is not set
# CONFIG_SLIP is not set

#
# Wireless LAN (non-hamradio)
#
# CONFIG_NET_RADIO is not set

#
# Token Ring devices
#
# CONFIG_TR is not set
# CONFIG_NET_FC is not set
# CONFIG_RCPCI is not set
# CONFIG_SHAPER is not set
# CONFIG_NETCONSOLE is not set

#
# Wan interfaces
#
# CONFIG_WAN is not set

#
# Amateur Radio support
#
# CONFIG_HAMRADIO is not set

#
# IrDA (infrared) support
#
# CONFIG_IRDA is not set

#
# Bluetooth support
#
# CONFIG_BT is not set
CONFIG_KGDBOE=y
CONFIG_NETPOLL=y
CONFIG_NETPOLL_RX=y
CONFIG_NETPOLL_TRAP=y
CONFIG_NET_POLL_CONTROLLER=y

#
# ISDN subsystem
#
# CONFIG_ISDN is not set

#
# Telephony Support
#
# CONFIG_PHONE is not set

#
# Input device support
#
CONFIG_INPUT=y

#
# Userland interfaces
#
CONFIG_INPUT_MOUSEDEV=y
CONFIG_INPUT_MOUSEDEV_PSAUX=y
CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
# CONFIG_INPUT_JOYDEV is not set
# CONFIG_INPUT_TSDEV is not set
# CONFIG_INPUT_EVDEV is not set
# CONFIG_INPUT_EVBUG is not set

#
# Input I/O drivers
#
# CONFIG_GAMEPORT is not set
CONFIG_SOUND_GAMEPORT=y
CONFIG_SERIO=y
CONFIG_SERIO_I8042=y
CONFIG_SERIO_SERPORT=y
# CONFIG_SERIO_CT82C710 is not set
# CONFIG_SERIO_PCIPS2 is not set

#
# Input Device Drivers
#
CONFIG_INPUT_KEYBOARD=y
CONFIG_KEYBOARD_ATKBD=y
# CONFIG_KEYBOARD_SUNKBD is not set
# CONFIG_KEYBOARD_XTKBD is not set
# CONFIG_KEYBOARD_NEWTON is not set
CONFIG_INPUT_MOUSE=y
CONFIG_MOUSE_PS2=y
# CONFIG_MOUSE_SERIAL is not set
# CONFIG_MOUSE_INPORT is not set
# CONFIG_MOUSE_LOGIBM is not set
# CONFIG_MOUSE_PC110PAD is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set

#
# Character devices
#
CONFIG_VT=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
# CONFIG_SERIAL_NONSTANDARD is not set

#
# Serial drivers
#
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_NR_UARTS=4
# CONFIG_SERIAL_8250_EXTENDED is not set

#
# Non-8250 serial port support
#
CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y
CONFIG_UNIX98_PTYS=y
CONFIG_LEGACY_PTYS=y
CONFIG_LEGACY_PTY_COUNT=256

#
# Mice
#
# CONFIG_BUSMOUSE is not set
# CONFIG_QIC02_TAPE is not set

#
# IPMI
#
# CONFIG_IPMI_HANDLER is not set

#
# Watchdog Cards
#
# CONFIG_WATCHDOG is not set
# CONFIG_HW_RANDOM is not set
# CONFIG_NVRAM is not set
CONFIG_RTC=m
# CONFIG_GEN_RTC is not set
# CONFIG_DTLK is not set
# CONFIG_R3964 is not set
# CONFIG_APPLICOM is not set
# CONFIG_SONYPI is not set

#
# Ftape, the floppy tape device driver
#
# CONFIG_AGP is not set
# CONFIG_DRM is not set
# CONFIG_MWAVE is not set
CONFIG_RAW_DRIVER=y
CONFIG_MAX_RAW_DEVS=256
# CONFIG_HANGCHECK_TIMER is not set

#
# I2C support
#
# CONFIG_I2C is not set

#
# Misc devices
#
# CONFIG_IBM_ASM is not set

#
# Multimedia devices
#
# CONFIG_VIDEO_DEV is not set

#
# Digital Video Broadcasting Devices
#
# CONFIG_DVB is not set

#
# Graphics support
#
# CONFIG_FB is not set
# CONFIG_VIDEO_SELECT is not set

#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
# CONFIG_MDA_CONSOLE is not set
CONFIG_DUMMY_CONSOLE=y

#
# Sound
#
# CONFIG_SOUND is not set

#
# USB support
#
CONFIG_USB=m
# CONFIG_USB_DEBUG is not set

#
# Miscellaneous USB options
#
CONFIG_USB_DEVICEFS=y
# CONFIG_USB_BANDWIDTH is not set
# CONFIG_USB_DYNAMIC_MINORS is not set

#
# USB Host Controller Drivers
#
# CONFIG_USB_EHCI_HCD is not set
CONFIG_USB_OHCI_HCD=m
# CONFIG_USB_UHCI_HCD is not set

#
# USB Device Class drivers
#
# CONFIG_USB_BLUETOOTH_TTY is not set
# CONFIG_USB_ACM is not set
# CONFIG_USB_PRINTER is not set
CONFIG_USB_STORAGE=m
# CONFIG_USB_STORAGE_DEBUG is not set
# CONFIG_USB_STORAGE_DATAFAB is not set
# CONFIG_USB_STORAGE_FREECOM is not set
# CONFIG_USB_STORAGE_ISD200 is not set
# CONFIG_USB_STORAGE_DPCM is not set
# CONFIG_USB_STORAGE_HP8200e is not set
# CONFIG_USB_STORAGE_SDDR09 is not set
# CONFIG_USB_STORAGE_SDDR55 is not set
# CONFIG_USB_STORAGE_JUMPSHOT is not set

#
# USB Human Interface Devices (HID)
#
CONFIG_USB_HID=m
CONFIG_USB_HIDINPUT=y
# CONFIG_HID_FF is not set
# CONFIG_USB_HIDDEV is not set

#
# USB HID Boot Protocol drivers
#
# CONFIG_USB_KBD is not set
# CONFIG_USB_MOUSE is not set
# CONFIG_USB_AIPTEK is not set
# CONFIG_USB_WACOM is not set
# CONFIG_USB_KBTAB is not set
# CONFIG_USB_POWERMATE is not set
# CONFIG_USB_MTOUCH is not set
# CONFIG_USB_XPAD is not set
# CONFIG_USB_ATI_REMOTE is not set

#
# USB Imaging devices
#
# CONFIG_USB_MDC800 is not set
# CONFIG_USB_MICROTEK is not set
# CONFIG_USB_HPUSBSCSI is not set

#
# USB Multimedia devices
#
# CONFIG_USB_DABUSB is not set

#
# Video4Linux support is needed for USB Multimedia device support
#

#
# USB Network adaptors
#
# CONFIG_USB_CATC is not set
# CONFIG_USB_KAWETH is not set
# CONFIG_USB_PEGASUS is not set
# CONFIG_USB_RTL8150 is not set
# CONFIG_USB_USBNET is not set

#
# USB port drivers
#

#
# USB Serial Converter support
#
# CONFIG_USB_SERIAL is not set

#
# USB Miscellaneous drivers
#
# CONFIG_USB_EMI62 is not set
# CONFIG_USB_EMI26 is not set
# CONFIG_USB_TIGL is not set
# CONFIG_USB_AUERSWALD is not set
# CONFIG_USB_RIO500 is not set
# CONFIG_USB_LEGOTOWER is not set
# CONFIG_USB_BRLVGER is not set
# CONFIG_USB_LCD is not set
# CONFIG_USB_LED is not set
# CONFIG_USB_TEST is not set

#
# USB Gadget Support
#
# CONFIG_USB_GADGET is not set

#
# File systems
#
CONFIG_EXT2_FS=y
# CONFIG_EXT2_FS_XATTR is not set
CONFIG_EXT3_FS=y
# CONFIG_EXT3_FS_XATTR is not set
CONFIG_JBD=y
# CONFIG_JBD_DEBUG is not set
CONFIG_REISERFS_FS=y
# CONFIG_REISERFS_CHECK is not set
# CONFIG_REISERFS_PROC_INFO is not set
CONFIG_JFS_FS=y
# CONFIG_JFS_POSIX_ACL is not set
# CONFIG_JFS_DEBUG is not set
# CONFIG_JFS_STATISTICS is not set
CONFIG_XFS_FS=y
# CONFIG_XFS_RT is not set
# CONFIG_XFS_QUOTA is not set
# CONFIG_XFS_SECURITY is not set
# CONFIG_XFS_POSIX_ACL is not set
# CONFIG_MINIX_FS is not set
# CONFIG_ROMFS_FS is not set
# CONFIG_QUOTA is not set
# CONFIG_AUTOFS_FS is not set
# CONFIG_AUTOFS4_FS is not set

#
# CD-ROM/DVD Filesystems
#
CONFIG_ISO9660_FS=y
CONFIG_JOLIET=y
CONFIG_ZISOFS=y
CONFIG_ZISOFS_FS=y
# CONFIG_UDF_FS is not set

#
# DOS/FAT/NT Filesystems
#
CONFIG_FAT_FS=y
CONFIG_MSDOS_FS=y
CONFIG_VFAT_FS=y
# CONFIG_NTFS_FS is not set

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
CONFIG_PROC_KCORE=y
CONFIG_SYSFS=y
CONFIG_DEVFS_FS=y
# CONFIG_DEVFS_MOUNT is not set
# CONFIG_DEVFS_DEBUG is not set
# CONFIG_DEVPTS_FS_XATTR is not set
CONFIG_TMPFS=y
# CONFIG_HUGETLBFS is not set
# CONFIG_HUGETLB_PAGE is not set
CONFIG_RAMFS=y

#
# Miscellaneous filesystems
#
# CONFIG_ADFS_FS is not set
# CONFIG_AFFS_FS is not set
# CONFIG_HFS_FS is not set
# CONFIG_HFSPLUS_FS is not set
# CONFIG_BEFS_FS is not set
# CONFIG_BFS_FS is not set
# CONFIG_EFS_FS is not set
# CONFIG_CRAMFS is not set
# CONFIG_VXFS_FS is not set
# CONFIG_HPFS_FS is not set
# CONFIG_QNX4FS_FS is not set
# CONFIG_SYSV_FS is not set
# CONFIG_UFS_FS is not set

#
# Network File Systems
#
CONFIG_NFS_FS=y
CONFIG_NFS_V3=y
# CONFIG_NFS_V4 is not set
# CONFIG_NFS_DIRECTIO is not set
CONFIG_NFSD=y
CONFIG_NFSD_V3=y
# CONFIG_NFSD_V4 is not set
# CONFIG_NFSD_TCP is not set
CONFIG_LOCKD=y
CONFIG_LOCKD_V4=y
CONFIG_EXPORTFS=y
CONFIG_SUNRPC=y
# CONFIG_SUNRPC_GSS is not set
# CONFIG_SMB_FS is not set
# CONFIG_CIFS is not set
# CONFIG_NCP_FS is not set
# CONFIG_CODA_FS is not set
# CONFIG_AFS_FS is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y

#
# Native Language Support
#
CONFIG_NLS=y
CONFIG_NLS_DEFAULT="iso8859-1"
# CONFIG_NLS_CODEPAGE_437 is not set
# CONFIG_NLS_CODEPAGE_737 is not set
# CONFIG_NLS_CODEPAGE_775 is not set
# CONFIG_NLS_CODEPAGE_850 is not set
# CONFIG_NLS_CODEPAGE_852 is not set
# CONFIG_NLS_CODEPAGE_855 is not set
# CONFIG_NLS_CODEPAGE_857 is not set
# CONFIG_NLS_CODEPAGE_860 is not set
# CONFIG_NLS_CODEPAGE_861 is not set
# CONFIG_NLS_CODEPAGE_862 is not set
# CONFIG_NLS_CODEPAGE_863 is not set
# CONFIG_NLS_CODEPAGE_864 is not set
# CONFIG_NLS_CODEPAGE_865 is not set
# CONFIG_NLS_CODEPAGE_866 is not set
# CONFIG_NLS_CODEPAGE_869 is not set
# CONFIG_NLS_CODEPAGE_936 is not set
# CONFIG_NLS_CODEPAGE_950 is not set
# CONFIG_NLS_CODEPAGE_932 is not set
# CONFIG_NLS_CODEPAGE_949 is not set
# CONFIG_NLS_CODEPAGE_874 is not set
# CONFIG_NLS_ISO8859_8 is not set
# CONFIG_NLS_CODEPAGE_1250 is not set
# CONFIG_NLS_CODEPAGE_1251 is not set
# CONFIG_NLS_ISO8859_1 is not set
# CONFIG_NLS_ISO8859_2 is not set
# CONFIG_NLS_ISO8859_3 is not set
# CONFIG_NLS_ISO8859_4 is not set
# CONFIG_NLS_ISO8859_5 is not set
# CONFIG_NLS_ISO8859_6 is not set
# CONFIG_NLS_ISO8859_7 is not set
# CONFIG_NLS_ISO8859_9 is not set
# CONFIG_NLS_ISO8859_13 is not set
# CONFIG_NLS_ISO8859_14 is not set
# CONFIG_NLS_ISO8859_15 is not set
# CONFIG_NLS_KOI8_R is not set
# CONFIG_NLS_KOI8_U is not set
# CONFIG_NLS_UTF8 is not set

#
# Profiling support
#
# CONFIG_PROFILING is not set

#
# Kernel hacking
#
CONFIG_DEBUG_KERNEL=y
CONFIG_EARLY_PRINTK=y
CONFIG_DEBUG_STACKOVERFLOW=y
# CONFIG_DEBUG_STACK_USAGE is not set
CONFIG_DEBUG_SLAB=y
CONFIG_MAGIC_SYSRQ=y
CONFIG_DEBUG_SPINLOCK=y
# CONFIG_DEBUG_PAGEALLOC is not set
# CONFIG_SPINLINE is not set
CONFIG_DEBUG_INFO=y
# CONFIG_LOCKMETER is not set
CONFIG_DEBUG_SPINLOCK_SLEEP=y
CONFIG_KGDB=y
# CONFIG_KGDB_9600BAUD is not set
# CONFIG_KGDB_19200BAUD is not set
# CONFIG_KGDB_38400BAUD is not set
# CONFIG_KGDB_57600BAUD is not set
CONFIG_KGDB_115200BAUD=y
CONFIG_KGDB_PORT=0x2f8
CONFIG_KGDB_IRQ=3
# CONFIG_KGDB_MORE is not set
CONFIG_NO_KGDB_CPUS=4
# CONFIG_KGDB_TS is not set
# CONFIG_STACK_OVERFLOW_TEST is not set
CONFIG_KGDB_CONSOLE=y
CONFIG_KGDB_SYSRQ=y
CONFIG_FRAME_POINTER=y
CONFIG_X86_FIND_SMP_CONFIG=y
CONFIG_X86_MPPARSE=y

#
# Security options
#
# CONFIG_SECURITY is not set

#
# Cryptographic options
#
CONFIG_CRYPTO=y
CONFIG_CRYPTO_HMAC=y
CONFIG_CRYPTO_NULL=m
CONFIG_CRYPTO_MD4=m
CONFIG_CRYPTO_MD5=m
CONFIG_CRYPTO_SHA1=m
CONFIG_CRYPTO_SHA256=m
CONFIG_CRYPTO_SHA512=m
CONFIG_CRYPTO_DES=m
CONFIG_CRYPTO_BLOWFISH=m
CONFIG_CRYPTO_TWOFISH=m
CONFIG_CRYPTO_SERPENT=m
CONFIG_CRYPTO_AES=m
CONFIG_CRYPTO_CAST5=m
CONFIG_CRYPTO_CAST6=m
CONFIG_CRYPTO_DEFLATE=m
CONFIG_CRYPTO_TEST=m

#
# Library routines
#
# CONFIG_CRC32 is not set
CONFIG_ZLIB_INFLATE=y
CONFIG_ZLIB_DEFLATE=m
CONFIG_X86_SMP=y
CONFIG_X86_HT=y
CONFIG_X86_BIOS_REBOOT=y
CONFIG_PC=y

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch
  2004-03-02 14:26     ` Kevin Corry
@ 2004-03-02 22:21       ` Andrew Morton
  2004-03-03  0:15         ` Miquel van Smoorenburg
  0 siblings, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2004-03-02 22:21 UTC (permalink / raw)
  To: Kevin Corry; +Cc: linux-kernel, miquels

Kevin Corry <kevcorry@us.ibm.com> wrote:
>
> > Changing down_read() in dm_any_congested to down_read_trylock() would
> > probably fix it for bdi_*_congested(). If you can tell me how to
> > reproduce it I can try a few things..
> 
> Switching to down_read_trylock() would certainly eliminate this problem, as 
> long as you don't *need* to check the congestion of the underlying devices 
> each time dm_any_congested() is called.

It's clear from the trace: we're doing down_read() inside
sync_sb_inodes()'s inode_lock.

Yes, a trylock would fix it up, but it's a bit sleazy.

And we might have another problem here: we're thnking about removing the
global plugging queue and switching disk plugging over to being a
per-address_space thing.  So blk_run_queues() goes away and is replaced with

	mapping->backing_dev_info.unplug(&mapping->backing_dev_info);

so we only unplug the queues which back the relevant address_space.

The top-level code will take the top-level queue's lock, and the
devicemapper's implementation of backing_dev_info.unplug() will be called
under the top-level queue lock and will need to perform the same
devicemapper table walk.  A trylock here will not be acceptable: if it
fails, a process hangs up for seconds or even minutes.

So for two reasons now, it's looking like that semaphore which protects the
devicemapper tables needs to become a spinlock.  One which has interesting
ranking properties.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch
  2004-03-02 22:21       ` Andrew Morton
@ 2004-03-03  0:15         ` Miquel van Smoorenburg
  0 siblings, 0 replies; 5+ messages in thread
From: Miquel van Smoorenburg @ 2004-03-03  0:15 UTC (permalink / raw)
  To: Andrew Morton; +Cc: Kevin Corry, linux-kernel, miquels

On Tue, 02 Mar 2004 23:21:34, Andrew Morton wrote:
> Kevin Corry <kevcorry@us.ibm.com> wrote:
> >
> > > Changing down_read() in dm_any_congested to down_read_trylock() would
> > > probably fix it for bdi_*_congested(). If you can tell me how to
> > > reproduce it I can try a few things..
> > 
> > Switching to down_read_trylock() would certainly eliminate this problem, as 
> > long as you don't *need* to check the congestion of the underlying devices 
> > each time dm_any_congested() is called.
> 
> It's clear from the trace: we're doing down_read() inside
> sync_sb_inodes()'s inode_lock.
> 
> Yes, a trylock would fix it up, but it's a bit sleazy.
>
> So for two reasons now, it's looking like that semaphore which protects the
> devicemapper tables needs to become a spinlock.  One which has interesting
> ranking properties.

Is that 2.6 material? If so, good. If not, the "passing up" congestion
method doesn't seem so bad after all, I think. At least it keeps the
backing_dev_info struct completely static ..

(I haven't tried 2.6.4-rc1-mm1 yet - the e1000 driver doesn't work for me
 in that kernel, so I can't reach the damn boxes).

Mike.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2004-03-03  0:15 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <cistron.200403011400.51008.kevcorry@us.ibm.com>
2004-03-01 20:00 ` 2.6.4-rc1-mm1: queue-congestion-dm-implementation patch Kevin Corry
2004-03-02 13:01   ` Miquel van Smoorenburg
2004-03-02 14:26     ` Kevin Corry
2004-03-02 22:21       ` Andrew Morton
2004-03-03  0:15         ` Miquel van Smoorenburg

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