BMC/Intel-BMC/linux.git/drivers/block/xen-blkback, branch dev-4.6

xen/blback: Fit the important information of the thread in 17 characters

2016-03-03T21:45:54+00:00

The processes names are truncated to 17, while we had the length of the process as name 20 - which meant that while we filled it out with various details - the last 3 characters (which had the queue number) never surfaced to the user-space. To simplify this and be able to fit the device name, domain id, and the queue number we remove the 'blkback' from the name. Prior to this patch the device name is "blkback.." for example: blkback.8.xvda, blkback.11.hda. With the multiqueue block backend we add "-%d" for the queue. But sadly this is already way past the limit so it gets stripped. Possible solution had been identified by Ian: http://lists.xenproject.org/archives/html/xen-devel/2015-05/msg03516.html " If you are pressed for space then the "xvd" is probably a bit redundant in a string which starts blkbk. The guest may not even call the device xvdN (iirc BSD has another prefix) any how, so having blkback say so seems of limited use anyway. Since this seems to not include a partition number how does this work in the split partition scheme? (i.e. one where the guest is given xvda1 and xvda2 rather than xvda with a partition table) [It will be 'blkback.8.xvda1', and 'blkback.11.xvda2'] Perhaps something derived from one of the schemes in http://xenbits.xen.org/docs/unstable/misc/vbd-interface.txt might be a better fit? After a bit of discussion (see http://lists.xenproject.org/archives/html/xen-devel/2015-12/msg01588.html) we settled on dropping the "blback" part. This will make it possible to have the .-: [1.xvda-0] [1.xvda-1] And we enough space to make it go up to: [32100.xvdfg9-5] Acked-by: Roger Pau Monné Reported-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk

xen-blkback: advertise indirect segment support earlier

2016-03-03T21:45:53+00:00

There's no reason to defer this until the connect phase, and in fact there are frontend implementations expecting this to be available earlier. Move it into the probe function. Acked-by: Roger Pau Monné Signed-off-by: Jan Beulich Cc: Bob Liu Signed-off-by: Konrad Rzeszutek Wilk

Merge branch 'for-4.5/drivers' of git://git.kernel.dk/linux-block

2016-01-22T02:19:38+00:00

Pull block driver updates from Jens Axboe: "This is the block driver pull request for 4.5, with the exception of NVMe, which is in a separate branch and will be posted after this one. This pull request contains: - A set of bcache stability fixes, which have been acked by Kent. These have been used and tested for more than a year by the community, so it's about time that they got in. - A set of drbd updates from the drbd team (Andreas, Lars, Philipp) and Markus Elfring, Oleg Drokin. - A set of fixes for xen blkback/front from the usual suspects, (Bob, Konrad) as well as community based fixes from Kiri, Julien, and Peng. - A 2038 time fix for sx8 from Shraddha, with a fix from me. - A small mtip32xx cleanup from Zhu Yanjun. - A null_blk division fix from Arnd" * 'for-4.5/drivers' of git://git.kernel.dk/linux-block: (71 commits) null_blk: use sector_div instead of do_div mtip32xx: restrict variables visible in current code module xen/blkfront: Fix crash if backend doesn't follow the right states. xen/blkback: Fix two memory leaks. xen/blkback: make st_ statistics per ring xen/blkfront: Handle non-indirect grant with 64KB pages xen-blkfront: Introduce blkif_ring_get_request xen-blkback: clear PF_NOFREEZE for xen_blkif_schedule() xen/blkback: Free resources if connect_ring failed. xen/blocks: Return -EXX instead of -1 xen/blkback: make pool of persistent grants and free pages per-queue xen/blkback: get the number of hardware queues/rings from blkfront xen/blkback: pseudo support for multi hardware queues/rings xen/blkback: separate ring information out of struct xen_blkif xen/blkfront: correct setting for xen_blkif_max_ring_order xen/blkfront: make persistent grants pool per-queue xen/blkfront: Remove duplicate setting of ->xbdev. xen/blkfront: Cleanup of comments, fix unaligned variables, and syntax errors. xen/blkfront: negotiate number of queues/rings to be used with backend xen/blkfront: split per device io_lock ...

xen/blkback: Fix two memory leaks.

2016-01-04T17:21:26+00:00

This patch fixs two memleaks: backtrace: [] kmemleak_alloc+0x28/0x50 [] kmem_cache_alloc+0xbb/0x1d0 [] xen_blkbk_probe+0x58/0x230 [] xenbus_dev_probe+0x76/0x130 [] driver_probe_device+0x166/0x2c0 [] __device_attach_driver+0xac/0xb0 [] bus_for_each_drv+0x67/0x90 [] __device_attach+0xc7/0x120 [] device_initial_probe+0x13/0x20 [] bus_probe_device+0x9a/0xb0 [] device_add+0x3b1/0x5c0 [] device_register+0x1e/0x30 [] xenbus_probe_node+0x158/0x170 [] xenbus_dev_changed+0x1af/0x1c0 [] backend_changed+0x1b/0x20 [] xenwatch_thread+0xb6/0x160 unreferenced object 0xffff880007ba8ef8 (size 224): backtrace: [] kmemleak_alloc+0x28/0x50 [] __kmalloc+0xd3/0x1e0 [] frontend_changed+0x2c7/0x580 [] xenbus_otherend_changed+0xa2/0xb0 [] frontend_changed+0x10/0x20 [] xenwatch_thread+0xb6/0x160 [] kthread+0xd7/0xf0 [] ret_from_fork+0x3f/0x70 [] 0xffffffffffffffff unreferenced object 0xffff8800048dcd38 (size 224): The first leak is caused by not put() the be->blkif reference which we had gotten in xen_blkif_alloc(), while the second is us not freeing blkif->rings in the right place. Signed-off-by: Bob Liu Reported-and-Tested-by: Konrad Rzeszutek Wilk Signed-off-by: Konrad Rzeszutek Wilk

xen/blkback: make st_ statistics per ring

2016-01-04T17:21:25+00:00

Make st_* statistics per ring and the VBD sysfs would iterate over all the rings. Note: xenvbd_sysfs_delif() is called in xen_blkbk_remove() before all rings are torn down, so it's safe. Signed-off-by: Bob Liu Signed-off-by: Konrad Rzeszutek Wilk --- v2: Aligned the variables on the same column.

xen-blkback: clear PF_NOFREEZE for xen_blkif_schedule()

2016-01-04T17:21:24+00:00

xen_blkif_schedule() kthread calls try_to_freeze() at the beginning of every attempt to purge the LRU. This operation can't ever succeed though, as the kthread hasn't marked itself as freezable. Before (hopefully eventually) kthread freezing gets converted to fileystem freezing, we'd rather mark xen_blkif_schedule() freezable (as it can generate I/O during suspend). Signed-off-by: Jiri Kosina Signed-off-by: Konrad Rzeszutek Wilk

xen/blkback: Free resources if connect_ring failed.

2016-01-04T17:21:07+00:00

With the multi-queue support we could fail at setting up some of the rings and fail the connection. That meant that all resources tied to rings[0..n-1] (where n is the ring that failed to be setup). Eventually the frontend will switch to the states and we will call xen_blkif_disconnect. However we do not want to be at the mercy of the frontend deciding when to change states. This allows us to do the cleanup right away and freeing resources. Signed-off-by: Konrad Rzeszutek Wilk

xen/blocks: Return -EXX instead of -1

2016-01-04T17:21:07+00:00

Lets return sensible values instead of -1. Signed-off-by: Konrad Rzeszutek Wilk

xen/blkback: make pool of persistent grants and free pages per-queue

2016-01-04T17:21:06+00:00

Make pool of persistent grants and free pages per-queue/ring instead of per-device to get better scalability. Test was done based on null_blk driver: dom0: v4.2-rc8 16vcpus 10GB "modprobe null_blk" domu: v4.2-rc8 16vcpus 10GB [test] rw=read direct=1 ioengine=libaio bs=4k time_based runtime=30 filename=/dev/xvdb numjobs=16 iodepth=64 iodepth_batch=64 iodepth_batch_complete=64 group_reporting Results: iops1: After patch "xen/blkfront: make persistent grants per-queue". iops2: After this patch. Queues: 1 4 8 16 Iops orig(k): 810 1064 780 700 Iops1(k): 810 1230(~20%) 1024(~20%) 850(~20%) Iops2(k): 810 1410(~35%) 1354(~75%) 1440(~100%) With 4 queues after this commit we can get ~75% increase in IOPS, and performance won't drop if increasing queue numbers. Please find the respective chart in this link: https://www.dropbox.com/s/agrcy2pbzbsvmwv/iops.png?dl=0 Signed-off-by: Bob Liu Signed-off-by: Konrad Rzeszutek Wilk

xen/blkback: get the number of hardware queues/rings from blkfront

2016-01-04T17:21:06+00:00

Backend advertises "multi-queue-max-queues" to front, also get the negotiated number from "multi-queue-num-queues" written by blkfront. Signed-off-by: Bob Liu Signed-off-by: Konrad Rzeszutek Wilk