- 05 Aug, 2021 2 commits
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Bart Van Assche authored
We noticed that the user interface of Android devices becomes very slow under memory pressure. This is because Android uses the zram driver on top of the loop driver for swapping, because under memory pressure the swap code alternates reads and writes quickly, because mq-deadline is the default scheduler for loop devices and because mq-deadline delays writes by five seconds for such a workload with default settings. Fix this by making the kernel select I/O scheduler 'none' from inside add_disk() for loop devices. This default can be overridden at any time from user space, e.g. via a udev rule. This approach has an advantage compared to changing the I/O scheduler from userspace from 'mq-deadline' into 'none', namely that synchronize_rcu() does not get called. This patch changes the default I/O scheduler for loop devices from 'mq-deadline' into 'none'. Additionally, this patch reduces the Android boot time on my test setup with 0.5 seconds compared to configuring the loop I/O scheduler from user space. Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Martijn Coenen <maco@android.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by:
Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20210805174200.3250718-3-bvanassche@acm.orgSigned-off-by:
Jens Axboe <axboe@kernel.dk>
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Bart Van Assche authored
elevator_get_default() uses the following algorithm to select an I/O scheduler from inside add_disk(): - In case of a single hardware queue or if sharing hardware queues across multiple request queues (BLK_MQ_F_TAG_HCTX_SHARED), use mq-deadline. - Otherwise, use 'none'. This is a good choice for most but not for all block drivers. Make it possible to override the selection of mq-deadline with a new flag, namely BLK_MQ_F_NO_SCHED_BY_DEFAULT. Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Martijn Coenen <maco@android.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by:
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- 02 Aug, 2021 38 commits
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Damien Le Moal authored
In block/blk-mq-sysfs.c, struct blk_mq_ctx_sysfs_entry is not used to define any attribute since the "mq" sysfs directory contains only sub-directories (no attribute files). As a result, blk_mq_sysfs_show(), blk_mq_sysfs_store(), and struct sysfs_ops blk_mq_sysfs_ops are all unused and unnecessary. Remove all this unused code. Signed-off-by:
Damien Le Moal <damien.lemoal@wdc.com> Link: https://lore.kernel.org/r/20210713081837.524422-1-damien.lemoal@wdc.comSigned-off-by:
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Matteo Croce authored
Make the loop device raise a DISK_MEDIA_CHANGE event on attach or detach. # udevadm monitor -up |grep -e DISK_MEDIA_CHANGE -e DEVNAME & # losetup -f zero [ 7.454235] loop0: detected capacity change from 0 to 16384 DISK_MEDIA_CHANGE=1 DEVNAME=/dev/loop0 DEVNAME=/dev/loop0 DEVNAME=/dev/loop0 # losetup -f zero [ 10.205245] loop1: detected capacity change from 0 to 16384 DISK_MEDIA_CHANGE=1 DEVNAME=/dev/loop1 DEVNAME=/dev/loop1 DEVNAME=/dev/loop1 # losetup -f zero2 [ 13.532368] loop2: detected capacity change from 0 to 40960 DISK_MEDIA_CHANGE=1 DEVNAME=/dev/loop2 DEVNAME=/dev/loop2 # losetup -D DEVNAME=/dev/loop1 DISK_MEDIA_CHANGE=1 DEVNAME=/dev/loop1 DEVNAME=/dev/loop2 DISK_MEDIA_CHANGE=1 DEVNAME=/dev/loop2 DEVNAME=/dev/loop0 DISK_MEDIA_CHANGE=1 DEVNAME=/dev/loop0 Signed-off-by:
Matteo Croce <mcroce@microsoft.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Tested-by:
Luca Boccassi <bluca@debian.org> Link: https://lore.kernel.org/r/20210712230530.29323-7-mcroce@linux.microsoft.comSigned-off-by:
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Matteo Croce authored
Refactor disk_check_events() and move some code into disk_event_uevent(). Then add disk_force_media_change(), a helper which will be used by devices to force issuing a DISK_EVENT_MEDIA_CHANGE event. Co-developed-by:
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Matteo Croce authored
Add a new sysfs handle to export the new diskseq value. Place it in <sysfs>/block/<disk>/diskseq and document it. $ grep . /sys/class/block/*/diskseq /sys/class/block/loop0/diskseq:13 /sys/class/block/loop1/diskseq:14 /sys/class/block/loop2/diskseq:5 /sys/class/block/loop3/diskseq:6 /sys/class/block/ram0/diskseq:1 /sys/class/block/ram1/diskseq:2 /sys/class/block/vda/diskseq:7 Reviewed-by: -
Matteo Croce authored
Add a new BLKGETDISKSEQ ioctl which retrieves the disk sequence number from the genhd structure. # ./getdiskseq /dev/loop* /dev/loop0: 13 /dev/loop0p1: 13 /dev/loop0p2: 13 /dev/loop0p3: 13 /dev/loop1: 14 /dev/loop1p1: 14 /dev/loop1p2: 14 /dev/loop2: 5 /dev/loop3: 6 Reviewed-by: -
Matteo Croce authored
Export the newly introduced diskseq in uevents: $ udevadm info /sys/class/block/* |grep -e DEVNAME -e DISKSEQ E: DEVNAME=/dev/loop0 E: DISKSEQ=1 E: DEVNAME=/dev/loop1 E: DISKSEQ=2 E: DEVNAME=/dev/loop2 E: DISKSEQ=3 E: DEVNAME=/dev/loop3 E: DISKSEQ=4 E: DEVNAME=/dev/loop4 E: DISKSEQ=5 E: DEVNAME=/dev/loop5 E: DISKSEQ=6 E: DEVNAME=/dev/loop6 E: DISKSEQ=7 E: DEVNAME=/dev/loop7 E: DISKSEQ=8 E: DEVNAME=/dev/nvme0n1 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p1 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p2 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p3 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p4 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p5 E: DISKSEQ=9 E: DEVNAME=/dev/sda E: DISKSEQ=10 E: DEVNAME=/dev/sda1 E: DISKSEQ=10 E: DEVNAME=/dev/sda2 E: DISKSEQ=10 Reviewed-by: -
Matteo Croce authored
Associating uevents with block devices in userspace is difficult and racy: the uevent netlink socket is lossy, and on slow and overloaded systems has a very high latency. Block devices do not have exclusive owners in userspace, any process can set one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0 can be reused again and again). A userspace process setting up a block device and watching for its events cannot thus reliably tell whether an event relates to the device it just set up or another earlier instance with the same name. Being able to set a UUID on a loop device would solve the race conditions. But it does not allow to derive orderings from uevents: if you see a uevent with a UUID that does not match the device you are waiting for, you cannot tell whether it's because the right uevent has not arrived yet, or it was already sent and you missed it. So you cannot tell whether you should wait for it or not. Associating a unique, monotonically increasing sequential number to the lifetime of each block device, which can be retrieved with an ioctl immediately upon setting it up, allows to solve the race conditions with uevents, and also allows userspace processes to know whether they should wait for the uevent they need or if it was dropped and thus they should move on. Additionally, increment the disk sequence number when the media change, i.e. on DISK_EVENT_MEDIA_CHANGE event. Reviewed-by:
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Christoph Hellwig authored
cmdline-parser.c is only used by the cmdline faux partition format, so merge the code into that and avoid an indirect call. Signed-off-by:
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Christoph Hellwig authored
Remove the disk_name function now that all users are gone. Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210727062518.122108-7-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
disk_name for partition 0 just copies out the disk_name field. Replace the call to disk_name with a %s format specifier. Signed-off-by:
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Christoph Hellwig authored
Printk ->disk_name directly for the disk and use the %pg format specifier for the block device, which is equivalent to a bdevname call. Signed-off-by:
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Christoph Hellwig authored
Simplify printing the partition name by using the %pg format specifier that is equivalent to a bdevname call. Signed-off-by:
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Christoph Hellwig authored
Simplify printing the partition name by using the %pg format specifier that is equivalent to a bdevname call. Signed-off-by:
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Abd-Alrhman Masalkhi authored
I have compiled the kernel with a cross compiler "hppa-linux-gnu-" v9.3.0 on x86-64 host machine. I got the following warning: block/genhd.c: In function ‘diskstats_show’: block/genhd.c:1227:1: warning: the frame size of 1688 bytes is larger than 1280 bytes [-Wframe-larger-than=] 1227 | } By Reduced the stack footprint by using the %pg printk specifier instead of disk_name to remove the need for the on-stack buffer. Signed-off-by:
Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> Signed-off-by:
Hannes Reinecke <hare@suse.de> Reviewed-by:
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Christoph Hellwig authored
Now that we've stopped using inode references for anything meaninful in the block layer get rid of the helper to put it and just open code the call to iput on the block_device inode. Signed-off-by:
Josef Bacik <josef@toxicpanda.com> Reviewed-by:
Chaitanya Kulkarni <ckulkarnilinux@gmail.com> Link: https://lore.kernel.org/r/20210722075402.983367-10-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
All callers are gone, and no one should grab a pure inode reference to a block device anymore. Signed-off-by:
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Christoph Hellwig authored
The whole device block device won't be removed while the disk is still alive, so don't bother to grab a reference to it. Signed-off-by:
Ming Lei <ming.lei@rehat.com> Reviewed-by:
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Christoph Hellwig authored
Instead of acquiring an inode reference on open make sure partitions always hold device model references to the disk while alive, and switch open to grab only a device model reference to the opened block device. If that is a partition the disk reference is transitively held by the partition already. Link: https://lore.kernel.org/r/20210722075402.983367-6-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Move the allocation of bd_meta_info after initializing the struct device to avoid the special bdput error handling path. Signed-off-by:
Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210722075402.983367-5-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Unhash the whole device inode early in del_gendisk. This allows to remove the first GENHD_FL_UP check in the open path as we simply won't find a just removed inode. The second non-racy check after taking open_mutex is still kept. Signed-off-by:
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Christoph Hellwig authored
Add a lockdep assert instead of the outdated locking comment. Signed-off-by:
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Christoph Hellwig authored
Using local kmaps slightly reduces the chances to stray writes, and the bvec interface cleans up the code a little bit. Signed-off-by:
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Christoph Hellwig authored
Using local kmaps slightly reduces the chances to stray writes, and the bvec interface cleans up the code a little bit. Signed-off-by:
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Christoph Hellwig authored
Rewrite the actual bounce buffering loop in __blk_queue_bounce to that the memcpy_to_bvec helper can be used to perform the data copies. Signed-off-by:
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Christoph Hellwig authored
Use memcpy_from_bvec instead of open coding the logic. Signed-off-by:
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Christoph Hellwig authored
Use memcpy_to_bvec instead of opencoding the logic. Signed-off-by:
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Christoph Hellwig authored
Use the proper helpers instead of open coding the copy. Signed-off-by:
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Christoph Hellwig authored
These two helpers are entirely unused now. Signed-off-by:
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Christoph Hellwig authored
Use the bvec helpers instead of open coding the copy. Signed-off-by:
Geoff Levand <geoff@infradead.org> Link: https://lore.kernel.org/r/20210727055646.118787-9-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
There is no need to disable interrupts in bio_copy_block, and the local only mappings helps to avoid any sort of problems with stray writes into the bio data. Signed-off-by:
Ira Weiny <ira.weiny@intel.com> Link: https://lore.kernel.org/r/20210727055646.118787-8-hch@lst.deSigned-off-by:
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Christoph Hellwig authored
Use memzero_bvec instead of reimplementing it. Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Reviewed-by:
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Christoph Hellwig authored
Use memzero_bvec to zero each segment in the bio instead of manually mapping and zeroing the data. Signed-off-by:
Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by:
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Christoph Hellwig authored
Add helpers to perform common memory operation on a bvec. Signed-off-by:
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Christoph Hellwig authored
Add a helper to call kmap_local_page on a bvec. There is no need for an unmap helper given that kunmap_local accept any address in the mapped page. Signed-off-by:
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Christoph Hellwig authored
Fix the include guards to match the file naming. Signed-off-by:
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Christoph Hellwig authored
There is no need to include genhd.h from a random arch header, and not doing so prevents the possibility for nasty include loops. Signed-off-by:
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Oliver Hartkopp authored
systemd added a modified copy of include/linux/ioprio.h into its code to get the relevant content definitions for the exposed ioprio_[get|set] system calls. Move the user space relevant ioprio bits to the UAPI includes to be able to use the ioprio_[get|set] syscalls as intended. Cc: Kay Sievers <kay@vrfy.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Signed-off-by:
Oliver Hartkopp <socketcan@hartkopp.net> Link: https://lore.kernel.org/r/20210714195655.181943-1-socketcan@hartkopp.netSigned-off-by:
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Linus Torvalds authored
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