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2014-08-14Merge tag 'pci-v3.17-changes-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull DEFINE_PCI_DEVICE_TABLE removal from Bjorn Helgaas: "Part two of the PCI changes for v3.17: - Remove DEFINE_PCI_DEVICE_TABLE macro use (Benoit Taine) It's a mechanical change that removes uses of the DEFINE_PCI_DEVICE_TABLE macro. I waited until later in the merge window to reduce conflicts, but it's possible you'll still see a few" * tag 'pci-v3.17-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: PCI: Remove DEFINE_PCI_DEVICE_TABLE macro use
2014-08-14Merge branch 'for-3.17/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block driver changes from Jens Axboe: "Nothing out of the ordinary here, this pull request contains: - A big round of fixes for bcache from Kent Overstreet, Slava Pestov, and Surbhi Palande. No new features, just a lot of fixes. - The usual round of drbd updates from Andreas Gruenbacher, Lars Ellenberg, and Philipp Reisner. - virtio_blk was converted to blk-mq back in 3.13, but now Ming Lei has taken it one step further and added support for actually using more than one queue. - Addition of an explicit SG_FLAG_Q_AT_HEAD for block/bsg, to compliment the the default behavior of adding to the tail of the queue. From Douglas Gilbert" * 'for-3.17/drivers' of git://git.kernel.dk/linux-block: (86 commits) bcache: Drop unneeded blk_sync_queue() calls bcache: add mutex lock for bch_is_open bcache: Correct printing of btree_gc_max_duration_ms bcache: try to set b->parent properly bcache: fix memory corruption in init error path bcache: fix crash with incomplete cache set bcache: Fix more early shutdown bugs bcache: fix use-after-free in btree_gc_coalesce() bcache: Fix an infinite loop in journal replay bcache: fix crash in bcache_btree_node_alloc_fail tracepoint bcache: bcache_write tracepoint was crashing bcache: fix typo in bch_bkey_equal_header bcache: Allocate bounce buffers with GFP_NOWAIT bcache: Make sure to pass GFP_WAIT to mempool_alloc() bcache: fix uninterruptible sleep in writeback thread bcache: wait for buckets when allocating new btree root bcache: fix crash on shutdown in passthrough mode bcache: fix lockdep warnings on shutdown bcache allocator: send discards with correct size bcache: Fix to remove the rcu_sched stalls. ...
2014-08-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client Pull Ceph updates from Sage Weil: "There is a lot of refactoring and hardening of the libceph and rbd code here from Ilya that fix various smaller bugs, and a few more important fixes with clone overlap. The main fix is a critical change to the request_fn handling to not sleep that was exposed by the recent mutex changes (which will also go to the 3.16 stable series). Yan Zheng has several fixes in here for CephFS fixing ACL handling, time stamps, and request resends when the MDS restarts. Finally, there are a few cleanups from Himangi Saraogi based on Coccinelle" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (39 commits) libceph: set last_piece in ceph_msg_data_pages_cursor_init() correctly rbd: remove extra newlines from rbd_warn() messages rbd: allocate img_request with GFP_NOIO instead GFP_ATOMIC rbd: rework rbd_request_fn() ceph: fix kick_requests() ceph: fix append mode write ceph: fix sizeof(struct tYpO *) typo ceph: remove redundant memset(0) rbd: take snap_id into account when reading in parent info rbd: do not read in parent info before snap context rbd: update mapping size only on refresh rbd: harden rbd_dev_refresh() and callers a bit rbd: split rbd_dev_spec_update() into two functions rbd: remove unnecessary asserts in rbd_dev_image_probe() rbd: introduce rbd_dev_header_info() rbd: show the entire chain of parent images ceph: replace comma with a semicolon rbd: use rbd_segment_name_free() instead of kfree() ceph: check zero length in ceph_sync_read() ceph: reset r_resend_mds after receiving -ESTALE ...
2014-08-12PCI: Remove DEFINE_PCI_DEVICE_TABLE macro useBenoit Taine
We should prefer `struct pci_device_id` over `DEFINE_PCI_DEVICE_TABLE` to meet kernel coding style guidelines. This issue was reported by checkpatch. A simplified version of the semantic patch that makes this change is as follows (http://coccinelle.lip6.fr/): // <smpl> @@ identifier i; declarer name DEFINE_PCI_DEVICE_TABLE; initializer z; @@ - DEFINE_PCI_DEVICE_TABLE(i) + const struct pci_device_id i[] = z; // </smpl> [bhelgaas: add semantic patch] Signed-off-by: Benoit Taine <benoit.taine@lip6.fr> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-08-08block: use pci_zalloc_consistentJoe Perches
Remove the now unnecessary memset too. Signed-off-by: Joe Perches <joe@perches.com> Mike Miller <mike.miller@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-07rbd: remove extra newlines from rbd_warn() messagesIlya Dryomov
rbd_warn() string should be a single line - rbd_warn() appends \n. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
2014-08-07rbd: allocate img_request with GFP_NOIO instead GFP_ATOMICIlya Dryomov
Now that rbd_img_request_create() is called from work functions, no need to use GFP_ATOMIC. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-08-07rbd: rework rbd_request_fn()Ilya Dryomov
While it was never a good idea to sleep in request_fn(), commit 34c6bc2c919a ("locking/mutexes: Add extra reschedule point") made it a *bad* idea. mutex_lock() since 3.15 may reschedule *before* putting task on the mutex wait queue, which for tasks in !TASK_RUNNING state means block forever. request_fn() may be called with !TASK_RUNNING on the way to schedule() in io_schedule(). Offload request handling to a workqueue, one per rbd device, to avoid calling blocking primitives from rbd_request_fn(). Fixes: http://tracker.ceph.com/issues/8818 Cc: stable@vger.kernel.org # 3.16, needs backporting for 3.15 Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Tested-by: Eric Eastman <eric0e@aol.com> Tested-by: Greg Wilson <greg.wilson@keepertech.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-08-06zram: replace global tb_lock with fine grain lockWeijie Yang
Currently, we use a rwlock tb_lock to protect concurrent access to the whole zram meta table. However, according to the actual access model, there is only a small chance for upper user to access the same table[index], so the current lock granularity is too big. The idea of optimization is to change the lock granularity from whole meta table to per table entry (table -> table[index]), so that we can protect concurrent access to the same table[index], meanwhile allow the maximum concurrency. With this in mind, several kinds of locks which could be used as a per-entry lock were tested and compared: Test environment: x86-64 Intel Core2 Q8400, system memory 4GB, Ubuntu 12.04, kernel v3.15.0-rc3 as base, zram with 4 max_comp_streams LZO. iozone test: iozone -t 4 -R -r 16K -s 200M -I +Z (1GB zram with ext4 filesystem, take the average of 10 tests, KB/s) Test base CAS spinlock rwlock bit_spinlock ------------------------------------------------------------------- Initial write 1381094 1425435 1422860 1423075 1421521 Rewrite 1529479 1641199 1668762 1672855 1654910 Read 8468009 11324979 11305569 11117273 10997202 Re-read 8467476 11260914 11248059 11145336 10906486 Reverse Read 6821393 8106334 8282174 8279195 8109186 Stride read 7191093 8994306 9153982 8961224 9004434 Random read 7156353 8957932 9167098 8980465 8940476 Mixed workload 4172747 5680814 5927825 5489578 5972253 Random write 1483044 1605588 1594329 1600453 1596010 Pwrite 1276644 1303108 1311612 1314228 1300960 Pread 4324337 4632869 4618386 4457870 4500166 To enhance the possibility of access the same table[index] concurrently, set zram a small disksize(10MB) and let threads run with large loop count. fio test: fio --bs=32k --randrepeat=1 --randseed=100 --refill_buffers --scramble_buffers=1 --direct=1 --loops=3000 --numjobs=4 --filename=/dev/zram0 --name=seq-write --rw=write --stonewall --name=seq-read --rw=read --stonewall --name=seq-readwrite --rw=rw --stonewall --name=rand-readwrite --rw=randrw --stonewall (10MB zram raw block device, take the average of 10 tests, KB/s) Test base CAS spinlock rwlock bit_spinlock ------------------------------------------------------------- seq-write 933789 999357 1003298 995961 1001958 seq-read 5634130 6577930 6380861 6243912 6230006 seq-rw 1405687 1638117 1640256 1633903 1634459 rand-rw 1386119 1614664 1617211 1609267 1612471 All the optimization methods show a higher performance than the base, however, it is hard to say which method is the most appropriate. On the other hand, zram is mostly used on small embedded system, so we don't want to increase any memory footprint. This patch pick the bit_spinlock method, pack object size and page_flag into an unsigned long table.value, so as to not increase any memory overhead on both 32-bit and 64-bit system. On the third hand, even though different kinds of locks have different performances, we can ignore this difference, because: if zram is used as zram swapfile, the swap subsystem can prevent concurrent access to the same swapslot; if zram is used as zram-blk for set up filesystem on it, the upper filesystem and the page cache also prevent concurrent access of the same block mostly. So we can ignore the different performances among locks. Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Davidlohr Bueso <davidlohr@hp.com> Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06zram: use size_t instead of u16Minchan Kim
Some architectures (eg, hexagon and PowerPC) could use PAGE_SHIFT of 16 or more. In these cases u16 is not sufficiently large to represent a compressed page's size so use size_t. Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Weijie Yang <weijie.yang@samsung.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06zram: remove unused SECTOR_SIZE defineSergey Senozhatsky
Drop SECTOR_SIZE define, because it's not used. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Weijie Yang <weijie.yang@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06zram: rename struct `table' to `zram_table_entry'Sergey Senozhatsky
Andrew Morton has recently noted that `struct table' actually represents table entry and, thus, should be renamed. Rename to `zram_table_entry'. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Weijie Yang <weijie.yang@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-25rbd: take snap_id into account when reading in parent infoIlya Dryomov
If we are mapping a snapshot, we must read in the parent_overlap value of that snapshot instead of that of the base image. Not doing so may in particular result in us returning zeros instead of user data: # cat overlap-snap.sh #!/bin/bash rbd create --size 10 --image-format 2 foo FOO_DEV=$(rbd map foo) dd if=/dev/urandom of=$FOO_DEV bs=1M &>/dev/null echo "Base image" dd if=$FOO_DEV bs=1 count=16 skip=$(((4 << 20) - 8)) 2>/dev/null | xxd rbd snap create foo@snap rbd snap protect foo@snap rbd clone foo@snap bar rbd snap create bar@snap BAR_DEV=$(rbd map bar@snap) echo "Snapshot" dd if=$BAR_DEV bs=1 count=16 skip=$(((4 << 20) - 8)) 2>/dev/null | xxd rbd resize --allow-shrink --size 4 bar echo "Snapshot after base image resize" dd if=$BAR_DEV bs=1 count=16 skip=$(((4 << 20) - 8)) 2>/dev/null | xxd # ./overlap-snap.sh Base image 0000000: e781 e33b d34b 2225 6034 2845 a2e3 36ed ...;.K"%`4(E..6. Snapshot 0000000: e781 e33b d34b 2225 6034 2845 a2e3 36ed ...;.K"%`4(E..6. Resizing image: 100% complete...done. Snapshot after base image resize 0000000: e781 e33b d34b 2225 0000 0000 0000 0000 ...;.K"%........ Even though bar@snap is taken with the old bar parent_overlap (8M), reads from bar@snap beyond the new bar parent_overlap (4M) return zeroes. Fix it. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: do not read in parent info before snap contextIlya Dryomov
Currently rbd_dev_v2_header_info() reads in parent info before the snap context is read in. This is wrong, because we may need to look at the the parent_overlap value of the snapshot instead of that of the base image, for example when mapping a snapshot - see next commit. (When mapping a snapshot, all we got is its name and we need the snap context to translate that name into an id to know which parent info to look for.) The approach taken here is to make sure rbd_dev_v2_parent_info() is called after the snap context has been read in. The other approach would be to add a parent_overlap field to struct rbd_mapping and maintain it the same way rbd_mapping::size is maintained. The reason I chose the first approach is that the value of keeping around both base image values and the actual mapping values is unclear to me. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: update mapping size only on refreshIlya Dryomov
There is no sense in trying to update the mapping size before it's even been set. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: harden rbd_dev_refresh() and callers a bitIlya Dryomov
Recently discovered watch/notify problems showed that we really can't ignore errors in anything refresh related. Alas, currently there is not much we can do in response to those errors, except print warnings. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: split rbd_dev_spec_update() into two functionsIlya Dryomov
rbd_dev_spec_update() has two modes of operation, with nothing in common between them. Split it into two functions, one for each mode and make our expectations more clear. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: remove unnecessary asserts in rbd_dev_image_probe()Ilya Dryomov
spec->image_id assert doesn't buy us much and image_format is asserted in rbd_dev_header_name() and rbd_dev_header_info() anyway. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: introduce rbd_dev_header_info()Ilya Dryomov
A wrapper around rbd_dev_v{1,2}_header_info() to reduce duplication. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-25rbd: show the entire chain of parent imagesIlya Dryomov
Make /sys/bus/rbd/devices/<id>/parent show the entire chain of parent images. While at it, kernel sprintf() doesn't return negative values, casting to unsigned long long is no longer necessary and there is no good reason to split into multiple sprintf() calls. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Alex Elder <elder@linaro.org>
2014-07-24rbd: use rbd_segment_name_free() instead of kfree()Himangi Saraogi
Free memory allocated using kmem_cache_zalloc using kmem_cache_free rather than kfree. The helper rbd_segment_name_free does the job here. Its position is shifted above the calling function. The Coccinelle semantic patch that detects this change is as follows: // <smpl> @@ expression x,E,c; @@ x = \(kmem_cache_alloc\|kmem_cache_zalloc\|kmem_cache_alloc_node\)(c,...) ... when != x = E when != &x ?-kfree(x) +kmem_cache_free(c,x) // </smpl> Signed-off-by: Himangi Saraogi <himangi774@gmail.com> Acked-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
2014-07-23zram: avoid lockdep splat by revalidate_diskMinchan Kim
Sasha reported lockdep warning [1] introduced by [2]. It could be fixed by doing disk revalidation out of the init_lock. It's okay because disk capacity change is protected by init_lock so that revalidate_disk always sees up-to-date value so there is no race. [1] https://lkml.org/lkml/2014/7/3/735 [2] zram: revalidate disk after capacity change Fixes 2e32baea46ce ("zram: revalidate disk after capacity change"). Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: "Alexander E. Patrakov" <patrakov@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> CC: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-07-10drbd: silence underflow warning in read_in_block()Dan Carpenter
My static checker warns that "data_size" could be negative and underflow the limit check. The code looks suspicious but I don't know if it is a real bug. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: implicitly truncate cpu-maskLars Ellenberg
Don't error out with misleading "out of memory" if the cpu-mask has more bits set than there are CPUs. Just truncate to nr_cpu_ids implicitly. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: drop spurious parameters from _drbd_md_sync_page_ioLars Ellenberg
size is always 4096, page is always device->md_io.page. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: resync should only lock out specific rangesLars Ellenberg
During resync, if we need to block some specific incoming write because of active resync requests to that same range, we potentially caused *all* new application writes (to "cold" activity log extents) to block until this one request has been processed. Improve the do_submit() logic to * grab all incoming requests to some "incoming" list * process this list - move aside requests that are blocked by resync - prepare activity log transactions, - commit transactions and submit corresponding requests - if there are remaining requests that only wait for activity log extents to become free, stop the fast path (mark activity log as "starving") - iterate until no more requests are waiting for the activity log, but all potentially remaining requests are only blocked by resync * only then grab new incoming requests That way, very busy IO on currently "hot" activity log extents cannot starve scattered IO to "cold" extents. And blocked-by-resync requests are processed once resync traffic on the affected region has ceased, without blocking anything else. The only blocking mode left is when we cannot start requests to "cold" extents because all currently "hot" extents are actually used. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add per device data_gen_idLars Ellenberg
The data generation identifiers used to be exposed via sysfs at /sys/block/drbdX/drbd/meta_data/data_gen_id (out-of-tree), for advanced policy scripting. Bring that information over to debugfs. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add per connection oldest requestsLars Ellenberg
Information of former /sys/block/drbdX/drbd/oldest_requests is already with higher detail in these files: debugfs/drbd/resource/$name/in_flight_summary, debugfs/drbd/resource/$name/volumes/$vnr/oldest_requests This patch adds debugfs/drbd/resource/$name/connections/peer/oldest_requests Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add version tag to debugfs filesLars Ellenberg
Make the first line of debugfs files a version number, starting now with "v: 0". If we change content of presentation, we will bump that. Monitoring or diagnostic scritps that may parse these files can then easily know when they need to be reviewed. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add per volume oldest_requestsLars Ellenberg
Show oldest requests * pending master bio completion and, * if different, local disk bio completion. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add callback_historyLars Ellenberg
Add a per-connection worker thread callback_history with timing details, call site and callback function. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: Add in_flight_summaryLars Ellenberg
* Add details about pending meta data operations to in_flight_summary. * Report number of requests waiting for activity log transactions. * timing details of peer_requests to in_flight_summary. * FLUSH details DRBD devides the incoming request stream into "epochs", in which peers are allowed to re-order writes independendly. These epochs are separated by P_BARRIER on the replication link. Such barrier packets, depending on configuration, may cause the receiving side to drain the lower level device request queues and call blkdev_issue_flush(). This is known to be an other major source of latency in DRBD. Track timing details of calls to blkdev_issue_flush(), and add them to in_flight_summary. * data socket stats To be able to diagnose bottlenecks and root causes of "slow" IO on DRBD, it is useful to see network buffer stats along with the timing details of requests, peer requests, and meta data IO. * pending bitmap IO timing details to in_flight_summary. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: deal with destructor racing with open of debugfs fileLars Ellenberg
Try to close the race between open() and debugfs_remove_recursive() from inside an object destructor. Once open succeeds, the object should stay around. Open should not succeed if the object has already reached its destructor. This may be overkill, but to make that happen, we check for existence of a parent directory, "stale-ness" of "this" dentry, and serialize kref_get_unless_zero() on the outermost object relevant for this file with d_delete() on this dentry (using the parent's i_mutex). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add in_flight_summary dataLars Ellenberg
To help diagnosing "high latency" or "hung" IO situations on DRBD, present per drbd resource group a summary of operations currently in progress. First item is a list of oldest drbd_request objects waiting for various things: * still being prepared * waiting for activity log transaction * waiting for local disk * waiting to be sent * waiting for peer acknowledgement ("receive ack", "write ack") * waiting for peer epoch acknowledgement ("barrier ack") Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: debugfs: add basic hierarchyLars Ellenberg
Add new debugfs hierarchy /sys/kernel/debug/ drbd/ resources/ $resource_name/connections/peer/$volume_number/ $resource_name/volumes/$volume_number/ minors/$minor_number -> ../resources/$resource_name/volumes/$volume_number/ Followup commits will populate this hierarchy with files containing statistics, diagnostic information and some attribute data. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: track details of bitmap IOLars Ellenberg
Track start and submit time of bitmap operations, and add pending bitmap IO contexts to a new pending_bitmap_io list. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: register peer requests on read_ee earlyLars Ellenberg
Initialize peer_request with timestamp and proper empty list head. Add peer_request to list early, so debugfs can find this request and report it as "preparing", even if we sleep before we actually submit it. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: track timing details of peer_requestsLars Ellenberg
To be able to present timing details in debugfs, we need to track preparation/submit times of peer requests. Track peer request flags early, before they are put on the epoch_entry lists. Waiting for activity log transactions may be a major latency factor. We want to be able to present the peer_request state accurately in debugfs, and what it is waiting for. Consistently mark/unmark peer requests with EE_CALL_AL_COMPLETE_IO. Set it only *after* calling drbd_al_begin_io(), clear it as soon as we call drbd_al_complete_io(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: improve throttling decisions of background resynchronisationLars Ellenberg
Background resynchronisation does some "side-stepping", or throttles itself, if it detects application IO activity, and the current resync rate estimate is above the configured "cmin-rate". What was not detected: if there is no application IO, because it blocks on activity log transactions. Introduce a new atomic_t ap_actlog_cnt, tracking such blocked requests, and count non-zero as application IO activity. This counter is exposed at proc_details level 2 and above. Also make sure to release the currently locked resync extent if we side-step due to such voluntary throttling. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: add caching oldest request pointers for replication stagesLars Ellenberg
A request that is to be shipped to the peer goes through a few stages: - queued - sent, waiting for ack - ack received, waiting for "barrier ack", which is re-order epoch being closed on the peer by acknowledging a "cache flush" equivalent on the lower level device. In the later two stages, depending on protocol, we may have already completed this request to the upper layers, so it won't be found anymore on device->pending_master_completion[] lists. Track the oldest request yet to be sent (req_next), the oldest not yet acknowledged (req_ack_pending) and the oldest "still waiting for something from the peer" (req_not_net_done), doing short list walks on the transfer log to find the next pending one whenever such a request makes progress. Now we have a fast way to look up the oldest requests, don't do a transfer log walk every time. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: add lists to find oldest pending requestsLars Ellenberg
Adding requests to per-device fifo lists as soon as possible after allocating them leaves a simple list_first_entry_or_null() to find the oldest request, regardless what it is still waiting for. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: gather detailed timing statistics for drbd_requestsLars Ellenberg
Record (in jiffies) how much time a request spends in which stages. Followup commits will use and present this additional timing information so we can better locate and tackle the root causes of latency spikes, or present the backlog for asynchronous replication. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: track meta data IO intent, start and submit timeLars Ellenberg
For diagnostic purposes, track intent, start time and latest submit time of meta data IO. Move separate members from struct drbd_device into the embeded struct drbd_md_io. s/md_io_(page|in_use)/md_io.\1/ Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: fix drbd_destroy_device reference count updatesLars Ellenberg
drbd_destroy_device means to give up reference counts on the connection(s) reachable via the peer_device(s). It must not do that by iterating via device->resource->connections, resource and connections may have already been disassociated by drbd_free_resource, and we'd leak connection refs. Instead, iterate via device->peer_devices->connection. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: poison free'd device, resource and connection structsLars Ellenberg
Now that we have additional asynchronous kref_get/kref_put via debugfs, make sure we catch access after free. Poison struct drbd_device, drbd_connection and drbd_resource before kfree() with 0xfd, 0xfc, and 0xf2, respectively. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: also keep track of trim -> zero-out fallback peer_requestsLars Ellenberg
To be able to find and present such zero-out fallback peer_requests in debugfs, we add those to "active_ee", once that list drained. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: consistently use list_add_tail for peer_request trackingLars Ellenberg
Keep the epoch entry lists (active_ee, read_ee, sync_ee, ...) consistently "oldest first". That way finding the oldest not yet successfully processed request is simply list_first_entry_or_null. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: drop drbd_md_flushLars Ellenberg
The only user of drbd_md_flush was bm_rw(), and it is always followed by either a drbd_md_sync(), or an al_write_transaction(), which, if so configured, both end up submiting a FLUSH|FUA request anyways. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: add drbd_queue_work_if_unqueued helperLars Ellenberg
We sometimes do if (list_empty(&w.list)) drbd_queue_work(&q, &w.list); Removal (list_del_init) may happen outside all locks, after all pending work entries have been moved to an on-stack local work list. For not dynamically allocated, but embeded, work structs, we must avoid to re-add until it really was removed. Move that list_empty check inside the spin_lock(&q->q_lock) within the helper function, and change to list_empty_careful(). This may have been the reason for a list_add corruption inside drbd_queue_work(). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: drbd_rs_number_requests: fix unit mismatch in comparisonLars Ellenberg
We try to limit the number of "in-flight" resync requests. One condition for that is the amount of requested data should not exceed half of what can be covered by our "max-buffers" setting. However we compared number of 4k pages with number of in-flight 512 Byte sectors, and this extra throttle triggered much earlier than intended. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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