- 28 Mar, 2006 1 commit
-
-
Matt Mackall authored
Reading the CMOS clock on x86 and some other arches currently takes up to one second because it synchronizes with the CMOS second tick-over. This delay shows up at boot time as well a resume time. This is the currently the most substantial boot time delay for machines that are working towards instant-on capability. Also, a quick back of the envelope calculation (.5sec * 2M users * 1 boot a day * 10 years) suggests it has cost Linux users in the neighborhood of a million man-hours. An earlier thread on this topic is here: http://groups.google.com/group/linux.kernel/browse_frm/thread/8a24255215ff6151/2aa97e66a977653d?hl=en&lr=&ie=UTF-8&rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26selm%3D1To2R-2S7-11%40gated-at.bofh.it#2aa97e66a977653d ..from which the consensus seems to be that it's no longer desirable. In my view, there are basically four cases to consider: 1) networked, need precise walltime: use NTP 2) networked, don't need precise walltime: use NTP anyway 3) not networked, don't need sub-second precision walltime: don't care 4) not networked, need sub-second precision walltime: get a network or a radio time source because RTC isn't good enough anyway So this patch series simply removes the synchronization in favor of a simple seqlock-like approach using the seconds value. Note that for purposes of timer accuracy on wakeup, this patch will cause us to fire timers up to one second late. But as the current timer resume code will already sync once (or more!), it's no worse for short timers. Signed-off-by:
Matt Mackall <mpm@selenic.com> Cc: Andi Kleen <ak@muc.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
-
- 27 Mar, 2006 39 commits
-
-
Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: [SPARC64]: Fix off-by-1 error in TSB grow check.
-
Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: [NET]: drop duplicate assignment in request_sock [IPSEC]: Fix tunnel error handling in ipcomp6
-
git://brick.kernel.dk/data/git/linux-2.6-blockLinus Torvalds authored
* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block: [PATCH] Don't make debugfs depend on DEBUG_KERNEL [PATCH] Fix blktrace compile with sysfs not defined [PATCH] unused label in drivers/block/cciss. [BLOCK] increase size of disk stat counters [PATCH] blk_execute_rq_nowait-speedup [PATCH] ide-cd: quiet down GPCMD_READ_CDVD_CAPACITY failure [BLOCK] ll_rw_blk: kmalloc -> kzalloc conversion [PATCH] kzalloc() conversion in drivers/block [PATCH] update max_sectors documentation
-
NeilBrown authored
... being careful that mutex_trylock is inverted wrt down_trylock Signed-off-by:
Neil Brown <neilb@suse.de> Signed-off-by:
-
Arjan van de Ven authored
Semaphore to mutex conversion. The conversion was generated via scripts, and the result was validated automatically via a script as well. Signed-off-by:
Arjan van de Ven <arjan@infradead.org> Signed-off-by:
Ingo Molnar <mingo@elte.hu> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by:
-
NeilBrown authored
When retrying a write due to barrier failure, we don't reset 'remaining', so it goes negative and never hits 0 again. Signed-off-by:
-
NeilBrown authored
An md array can be asked to change the amount of each device that it is using, and in particular can be asked to use the maximum available space. This currently only works if the first device is not larger than the rest. As 'size' gets changed and so 'fit' becomes wrong. So check if a 'fit' is required early and don't corrupt it. Signed-off-by:
Doug Ledford <dledford@redhat.com> Signed-off-by:
-
NeilBrown authored
raid5 overloads bi_phys_segments to count the number of blocks that the request was broken in to so that it knows when the bio is completely handled. Accessing this must always be done under a spinlock. In one case we also call bi_end_io under that spinlock, which probably isn't ideal as bi_end_io could be expensive (even though it isn't allowed to sleep). So we reducde the range of the spinlock to just accessing bi_phys_segments. Signed-off-by:
-
NeilBrown authored
wait_event_lock_irq puts a ';' after its usage of the 4th arg, so we don't need to. Signed-off-by:
-
NeilBrown authored
Signed-off-by:
-
NeilBrown authored
This allows user-space to access data safely. This is needed for raid5 reshape as user-space needs to take a backup of the first few stripes before allowing reshape to commence. It will also be useful in cluster-aware raid1 configurations so that all cluster members can leave a section of the array untouched while a resync/recovery happens. A 'start' and 'end' of the suspended range are written to 2 sysfs attributes. Note that only one range can be suspended at a time. Signed-off-by:
-
NeilBrown authored
This allows reshape to be triggerred via sysfs (which is the only way to start it happening). Signed-off-by:
-
NeilBrown authored
check_reshape checks validity and does things that can be done instantly - like adding devices to raid1. start_reshape initiates a restriping process to convert the whole array. Signed-off-by:
-
NeilBrown authored
Instead of checkpointing at each stripe, only checkpoint when a new write would overwrite uncheckpointed data. Block any write to the uncheckpointed area. Arbitrarily checkpoint at least every 3Meg. Signed-off-by:
-
NeilBrown authored
We allow the superblock to record an 'old' and a 'new' geometry, and a position where any conversion is up to. The geometry allows for changing chunksize, layout and level as well as number of devices. When using verion-0.90 superblock, we convert the version to 0.91 while the conversion is happening so that an old kernel will refuse the assemble the array. For version-1, we use a feature bit for the same effect. When starting an array we check for an incomplete reshape and restart the reshape process if needed. If the reshape stopped at an awkward time (like when updating the first stripe) we refuse to assemble the array, and let user-space worry about it. Signed-off-by:
-
NeilBrown authored
This patch adds raid5_reshape and end_reshape which will start and finish the reshape processes. raid5_reshape is only enabled in CONFIG_MD_RAID5_RESHAPE is set, to discourage accidental use. Read the 'help' for the CONFIG_MD_RAID5_RESHAPE entry. and Make sure that you have backups, just in case. Signed-off-by:
-
NeilBrown authored
This patch provides the core of the resize/expand process. sync_request notices if a 'reshape' is happening and acts accordingly. It allocated new stripe_heads for the next chunk-wide-stripe in the target geometry, marking them STRIPE_EXPANDING. Then it finds which stripe heads in the old geometry can provide data needed by these and marks them STRIPE_EXPAND_SOURCE. This causes stripe_handle to read all blocks on those stripes. Once all blocks on a STRIPE_EXPAND_SOURCE stripe_head are read, any that are needed are copied into the corresponding STRIPE_EXPANDING stripe_head. Once a STRIPE_EXPANDING stripe_head is full, it is marks STRIPE_EXPAND_READY and then is written out and released. Signed-off-by:
-
NeilBrown authored
We need to allow that different stripes are of different effective sizes, and use the appropriate size. Also, when a stripe is being expanded, we must block any IO attempts until the stripe is stable again. Key elements in this change are: - each stripe_head gets a 'disk' field which is part of the key, thus there can sometimes be two stripe heads of the same area of the array, but covering different numbers of devices. One of these will be marked STRIPE_EXPANDING and so won't accept new requests. - conf->expand_progress tracks how the expansion is progressing and is used to determine whether the target part of the array has been expanded yet or not. Signed-off-by:
-
NeilBrown authored
Before a RAID-5 can be expanded, we need to be able to expand the stripe-cache data structure. This requires allocating new stripes in a new kmem_cache. If this succeeds, we copy cache pages over and release the old stripes and kmem_cache. We then allocate new pages. If that fails, we leave the stripe cache at it's new size. It isn't worth the effort to shrink it back again. Unfortuanately this means we need two kmem_cache names as we, for a short period of time, we have two kmem_caches. So they are raid5/%s and raid5/%s-alt Signed-off-by:
-
NeilBrown authored
The remainder of this batch implements raid5 reshaping. Currently the only shape change that is supported is added a device, but it is envisioned that changing the chunksize and layout will also be supported, as well as changing the level (e.g. 1->5, 5->6). The reshape process naturally has to move all of the data in the array, and so should be used with caution. It is believed to work, and some testing does support this, but wider testing would be great for increasing my confidence. You will need a version of mdadm newer than 2.3.1 to make use of raid5 growth. This is because mdadm need to take a copy of a 'critical section' at the start of the array incase there is a crash at an awkward moment. On restart, mdadm will restore the critical section and allow reshape to continue. I hope to release a 2.4-pre by early next week - it still needs a little more polishing. This patch: Previously the array of disk information was included in the raid5 'conf' structure which was allocated to an appropriate size. This makes it awkward to change the size of that array. So we split it off into a separate kmalloced array which will require a little extra indexing, but is much easier to grow. Signed-off-by:
-
NeilBrown authored
status_resync - used by /proc/mdstat to report the status of a resync, assumes that device sizes will always fit into an 'unsigned long' This is no longer the case... Signed-off-by:
-
NeilBrown authored
We are counting failed devices twice, once of the device that is failed, and once for the hole that has been left in the array. Remove the former so 'failed' matches 'missing'. Storing these counts in the superblock is a bit silly anyway.... Signed-off-by:
-
NeilBrown authored
I really should make this a function of the personality.... Signed-off-by:
-
NeilBrown authored
This flag should be set for a virtual device iff it is set for all underlying devices. Signed-off-by:
-
Kevin Corry authored
Signed-off-by:
Kevin Corry <kevcorry@us.ibm.com> Cc: Alasdair G Kergon <agk@redhat.com> Signed-off-by:
-
Jun'ichi Nomura authored
Convert bd_sem to bd_mutex Signed-off-by:
Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Alasdair G Kergon <agk@redhat.com> Signed-off-by:
-
Jun'ichi Nomura authored
Use bd_claim_by_disk. Following symlinks are created if dm-0 maps to sda: /sys/block/dm-0/slaves/sda --> /sys/block/sda /sys/block/sda/holders/dm-0 --> /sys/block/dm-0 Signed-off-by:
-
Jun'ichi Nomura authored
Use bd_claim_by_disk. Following symlinks are created if md0 is built from sda and sdb /sys/block/md0/slaves/sda --> /sys/block/sda /sys/block/md0/slaves/sdb --> /sys/block/sdb /sys/block/sda/holders/md0 --> /sys/block/md0 /sys/block/sdb/holders/md0 --> /sys/block/md0 Signed-off-by:
-
Jun'ichi Nomura authored
Adding bd_claim_by_kobject() function which takes kobject as additional signature of holder device and creates sysfs symlinks between holder device and claimed device. bd_release_from_kobject() is a counterpart of bd_claim_by_kobject. Signed-off-by:
-
Andrew Morton authored
Remove all the CONFIG_SYSFS stuff. That's supposed to all be implemented up in header files. Yes, the CONFIG_SYSFS=n data structures will be a little larger than necessary, but that's a tradeoff we can decide to make. Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Alasdair G Kergon <agk@redhat.com> Signed-off-by:
-
Jun'ichi Nomura authored
Creating "slaves" and "holders" directories in /sys/block/<disk> and creating "holders" directory under /sys/block/<disk>/<partition> Signed-off-by:
-
Darrick J. Wong authored
Allow drive geometry to be stored with a new DM_DEV_SET_GEOMETRY ioctl. Device-mapper will now respond to HDIO_GETGEO. If the geometry information is not available, zero will be returned for all of the parameters. Signed-off-by:
Darrick J. Wong <djwong@us.ibm.com> Signed-off-by:
Alasdair G Kergon <agk@redhat.com> Signed-off-by:
-
Mike Anderson authored
Store an up-pointer to the owning struct mapped_device in every table when it is created. Access it with: struct mapped_device *dm_table_get_md(struct dm_table *t) Tables linked to md must be destroyed before the md itself. Signed-off-by:
Mike Anderson <andmike@us.ibm.com> Signed-off-by:
-
Alasdair G Kergon authored
Change dm_get_mdptr() to take a struct mapped_device instead of dev_t. Signed-off-by:
-
Mike Anderson authored
The patch stores a printable device number in struct mapped_device for use in warning messages and with a proposed netlink interface. Signed-off-by:
-
Jun'ichi Nomura authored
If dm_suspend() is cancelled, bios already added to the deferred list need to be submitted. Otherwise they remain 'in limbo' until there's a dm_resume(). Signed-off-by:
-
Alasdair G Kergon authored
Before removing a snapshot, wait for the completion of any kcopyd jobs using it. Do this by maintaining a count (nr_jobs) of how many outstanding jobs each kcopyd_client has. The snapshot destructor first unregisters the snapshot so that no new kcopyd jobs (created by writes to the origin) will reference that particular snapshot. kcopyd_client_destroy() is now run next to wait for the completion of any outstanding jobs before the snapshot exception structures (that those jobs reference) are freed. Signed-off-by:
-
NeilBrown authored
This flag should be set for a virtual device iff it is set for all underlying devices. Signed-off-by:
-
Andrew Morton authored
We don't know what type sector_t has. Sometimes it's unsigned long, sometimes it's unsigned long long. For example on ppc64 it's unsigned long with CONFIG_LBD=n and on x86_64 it's unsigned long long with CONFIG_LBD=n. The way to handle all of this is to always use unsigned long long and to always typecast the sector_t when printing it. Acked-by:
-
