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2010-05-07blk-cgroup: Fix an RCU warning in blkiocg_create()Li Zefan
with CONFIG_PROVE_RCU=y, a warning can be triggered: # mount -t cgroup -o blkio xxx /mnt # mkdir /mnt/subgroup ... kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection! ... To fix this, we avoid caling css_depth() here, which is a bit simpler than the original code. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-12cgroups: blkio subsystem as moduleBen Blum
Modify the Block I/O cgroup subsystem to be able to be built as a module. As the CFQ disk scheduler optionally depends on blk-cgroup, config options in block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are enhanced to support the new module dependency. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-26cfq: Remove useless css reference getGui Jianfeng
There's no need to take css reference here, for the caller has already called rcu_read_lock() to prevent cgroup from being removed. Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-01blk-cgroup: Fix potential deadlock in blk-cgroupGui Jianfeng
I triggered a lockdep warning as following. ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.33-rc2 #1 ------------------------------------------------------- test_io_control/7357 is trying to acquire lock: (blkio_list_lock){+.+...}, at: [<c053a990>] blkiocg_weight_write+0x82/0x9e but task is already holding lock: (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&(&blkcg->lock)->rlock){......}: [<c04583b7>] validate_chain+0x8bc/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a [<c053a4e1>] blkiocg_add_blkio_group+0x1a/0x6d [<c053cac7>] cfq_get_queue+0x225/0x3de [<c053eec2>] cfq_set_request+0x217/0x42d [<c052c8a6>] elv_set_request+0x17/0x26 [<c0532a0f>] get_request+0x203/0x2c5 [<c0532ae9>] get_request_wait+0x18/0x10e [<c0533470>] __make_request+0x2ba/0x375 [<c0531985>] generic_make_request+0x28d/0x30f [<c0532da7>] submit_bio+0x8a/0x8f [<c04d827a>] submit_bh+0xf0/0x10f [<c04d91d2>] ll_rw_block+0xc0/0xf9 [<f86e9705>] ext3_find_entry+0x319/0x544 [ext3] [<f86eae58>] ext3_lookup+0x2c/0xb9 [ext3] [<c04c3e1b>] do_lookup+0xd3/0x172 [<c04c56c8>] link_path_walk+0x5fb/0x95c [<c04c5a65>] path_walk+0x3c/0x81 [<c04c5b63>] do_path_lookup+0x21/0x8a [<c04c66cc>] do_filp_open+0xf0/0x978 [<c04c0c7e>] open_exec+0x1b/0xb7 [<c04c1436>] do_execve+0xbb/0x266 [<c04081a9>] sys_execve+0x24/0x4a [<c04028a2>] ptregs_execve+0x12/0x18 -> #1 (&(&q->__queue_lock)->rlock){..-.-.}: [<c04583b7>] validate_chain+0x8bc/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a [<c053dd2a>] cfq_unlink_blkio_group+0x17/0x41 [<c053a6eb>] blkiocg_destroy+0x72/0xc7 [<c0467df0>] cgroup_diput+0x4a/0xb2 [<c04ca473>] dentry_iput+0x93/0xb7 [<c04ca4b3>] d_kill+0x1c/0x36 [<c04cb5c5>] dput+0xf5/0xfe [<c04c6084>] do_rmdir+0x95/0xbe [<c04c60ec>] sys_rmdir+0x10/0x12 [<c04027cc>] sysenter_do_call+0x12/0x32 -> #0 (blkio_list_lock){+.+...}: [<c0458117>] validate_chain+0x61c/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c06929fd>] _raw_spin_lock+0x1e/0x4e [<c053a990>] blkiocg_weight_write+0x82/0x9e [<c0467f1e>] cgroup_file_write+0xc6/0x1c0 [<c04bd2f3>] vfs_write+0x8c/0x116 [<c04bd7c6>] sys_write+0x3b/0x60 [<c04027cc>] sysenter_do_call+0x12/0x32 other info that might help us debug this: 1 lock held by test_io_control/7357: #0: (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e stack backtrace: Pid: 7357, comm: test_io_control Not tainted 2.6.33-rc2 #1 Call Trace: [<c045754f>] print_circular_bug+0x91/0x9d [<c0458117>] validate_chain+0x61c/0xb9c [<c0458dba>] __lock_acquire+0x723/0x789 [<c0458eb0>] lock_acquire+0x90/0xa7 [<c053a990>] ? blkiocg_weight_write+0x82/0x9e [<c06929fd>] _raw_spin_lock+0x1e/0x4e [<c053a990>] ? blkiocg_weight_write+0x82/0x9e [<c053a990>] blkiocg_weight_write+0x82/0x9e [<c0467f1e>] cgroup_file_write+0xc6/0x1c0 [<c0454df5>] ? trace_hardirqs_off+0xb/0xd [<c044d93a>] ? cpu_clock+0x2e/0x44 [<c050e6ec>] ? security_file_permission+0xf/0x11 [<c04bcdda>] ? rw_verify_area+0x8a/0xad [<c0467e58>] ? cgroup_file_write+0x0/0x1c0 [<c04bd2f3>] vfs_write+0x8c/0x116 [<c04bd7c6>] sys_write+0x3b/0x60 [<c04027cc>] sysenter_do_call+0x12/0x32 To prevent deadlock, we should take locks as following sequence: blkio_list_lock -> queue_lock -> blkcg_lock. The following patch should fix this bug. Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-07block: include linux/err.h to use ERR_PTRStephen Rothwell
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04blkio: Implement dynamic io controlling policy registrationVivek Goyal
o One of the goals of block IO controller is that it should be able to support mulitple io control policies, some of which be operational at higher level in storage hierarchy. o To begin with, we had one io controlling policy implemented by CFQ, and I hard coded the CFQ functions called by blkio. This created issues when CFQ is compiled as module. o This patch implements a basic dynamic io controlling policy registration functionality in blkio. This is similar to elevator functionality where ioschedulers register the functions dynamically. o Now in future, when more IO controlling policies are implemented, these can dynakically register with block IO controller. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04blkio: Export some symbols from blkio as its user CFQ can be a moduleVivek Goyal
o blkio controller is inside the kernel and cfq makes use of interfaces exported by blkio. CFQ can be a module too, hence export symbols used by CFQ. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04cfq-iosched: move IO controller declerations to a header fileJens Axboe
They should not be declared inside some other file that's not related to CFQ. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03blkio: Propagate cgroup weight updation to cfq groupsVivek Goyal
o Propagate blkio cgroup weight updation to associated cfq groups. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03blkio: Export disk time and sectors used by a group to user spaceVivek Goyal
o Export disk time and sector used by a group to user space through cgroup interface. o Also export a "dequeue" interface to cgroup which keeps track of how many a times a group was deleted from service tree. Helps in debugging. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03blkio: Some debugging aids for CFQVivek Goyal
o Some debugging aids for CFQ. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03blkio: Take care of cgroup deletion and cfq group reference countingVivek Goyal
o One can choose to change elevator or delete a cgroup. Implement group reference counting so that both elevator exit and cgroup deletion can take place gracefully. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Nauman Rafique <nauman@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03blkio: Introduce blkio controller cgroup interfaceVivek Goyal
o This is basic implementation of blkio controller cgroup interface. This is the common interface visible to user space and should be used by different IO control policies as we implement those. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>