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* ipc/sem.c: rename try_atomic_semop() to perform_atomic_semop(), docu updateManfred Spraul2013-07-09
| | | | | | | | | | | | | | | | | | Cleanup: Some minor points that I noticed while writing the previous patches 1) The name try_atomic_semop() is misleading: The function performs the operation (if it is possible). 2) Some documentation updates. No real code change, a rename and documentation changes. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Rik van Riel <riel@redhat.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: replace shared sem_otime with per-semaphore valueManfred Spraul2013-07-09
| | | | | | | | | | | | | | | | | | sem_otime contains the time of the last semaphore operation that completed successfully. Every operation updates this value, thus access from multiple cpus can cause thrashing. Therefore the patch replaces the variable with a per-semaphore variable. The per-array sem_otime is only calculated when required. No performance improvement on a single-socket i3 - only important for larger systems. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Rik van Riel <riel@redhat.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: always use only one queue for alter operationsManfred Spraul2013-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | There are two places that can contain alter operations: - the global queue: sma->pending_alter - the per-semaphore queues: sma->sem_base[].pending_alter. Since one of the queues must be processed first, this causes an odd priorization of the wakeups: complex operations have priority over simple ops. The patch restores the behavior of linux <=3.0.9: The longest waiting operation has the highest priority. This is done by using only one queue: - if there are complex ops, then sma->pending_alter is used. - otherwise, the per-semaphore queues are used. As a side effect, do_smart_update_queue() becomes much simpler: no more goto logic. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Rik van Riel <riel@redhat.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem: separate wait-for-zero and alter tasks into seperate queuesManfred Spraul2013-07-09
| | | | | | | | | | | | | | | | Introduce separate queues for operations that do not modify the semaphore values. Advantages: - Simpler logic in check_restart(). - Faster update_queue(): Right now, all wait-for-zero operations are always tested, even if the semaphore value is not 0. - wait-for-zero gets again priority, as in linux <=3.0.9 Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Rik van Riel <riel@redhat.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: cacheline align the semaphore structuresManfred Spraul2013-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As now each semaphore has its own spinlock and parallel operations are possible, give each semaphore its own cacheline. On a i3 laptop, this gives up to 28% better performance: #semscale 10 | grep "interleave 2" - before: Cpus 1, interleave 2 delay 0: 36109234 in 10 secs Cpus 2, interleave 2 delay 0: 55276317 in 10 secs Cpus 3, interleave 2 delay 0: 62411025 in 10 secs Cpus 4, interleave 2 delay 0: 81963928 in 10 secs -after: Cpus 1, interleave 2 delay 0: 35527306 in 10 secs Cpus 2, interleave 2 delay 0: 70922909 in 10 secs <<< + 28% Cpus 3, interleave 2 delay 0: 80518538 in 10 secs Cpus 4, interleave 2 delay 0: 89115148 in 10 secs <<< + 8.7% i3, with 2 cores and with hyperthreading enabled. Interleave 2 in order use first the full cores. HT partially hides the delay from cacheline trashing, thus the improvement is "only" 8.7% if 4 threads are running. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Rik van Riel <riel@redhat.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/util.c, ipc_rcu_alloc: cacheline align allocationManfred Spraul2013-07-09
| | | | | | | | | | | | | | | | | | | Enforce that ipc_rcu_alloc returns a cacheline aligned pointer on SMP. Rationale: The SysV sem code tries to move the main spinlock into a seperate cacheline (____cacheline_aligned_in_smp). This works only if ipc_rcu_alloc returns cacheline aligned pointers. vmalloc and kmalloc return cacheline algined pointers, the implementation of ipc_rcu_alloc breaks that. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Rik van Riel <riel@redhat.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: remove unused functionsDavidlohr Bueso2013-07-09
| | | | | | | | | | | We can now drop the msg_lock and msg_lock_check functions along with a bogus comment introduced previously in semctl_down. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,msg: shorten critical region in msgrcvDavidlohr Bueso2013-07-09
| | | | | | | | | | | | do_msgrcv() is the last msg queue function that abuses the ipc lock Take it only when needed when actually updating msq. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,msg: shorten critical region in msgsndDavidlohr Bueso2013-07-09
| | | | | | | | | | | | do_msgsnd() is another function that does too many things with the ipc object lock acquired. Take it only when needed when actually updating msq. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,msg: make msgctl_nolock locklessDavidlohr Bueso2013-07-09
| | | | | | | | | | | | | | While the INFO cmd doesn't take the ipc lock, the STAT commands do acquire it unnecessarily. We can do the permissions and security checks only holding the rcu lock. This function now mimics semctl_nolock(). Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,msg: introduce lockless functions to obtain the ipc objectDavidlohr Bueso2013-07-09
| | | | | | | | | | | | | Add msq_obtain_object() and msq_obtain_object_check(), which will allow us to get the ipc object without acquiring the lock. Just as with semaphores, these functions are basically wrappers around ipc_obtain_object*(). Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,msg: introduce msgctl_nolockDavidlohr Bueso2013-07-09
| | | | | | | | | | | | | | | Similar to semctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a msgctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). This change still takes the lock and it will be properly lockless in the next patch Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,msg: shorten critical region in msgctl_downDavidlohr Bueso2013-07-09
| | | | | | | | | | | | Instead of holding the ipc lock for the entire function, use the ipcctl_pre_down_nolock and only acquire the lock for specific commands: RMID and SET. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: move locking out of ipcctl_pre_down_nolockDavidlohr Bueso2013-07-09
| | | | | | | | | | | | | | | This function currently acquires both the rw_mutex and the rcu lock on successful lookups, leaving the callers to explicitly unlock them, creating another two level locking situation. Make the callers (including those that still use ipcctl_pre_down()) explicitly lock and unlock the rwsem and rcu lock. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: close open coded spin lock callsDavidlohr Bueso2013-07-09
| | | | | | | | Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: introduce ipc object locking helpersDavidlohr Bueso2013-07-09
| | | | | | | | | | Simple helpers around the (kern_ipc_perm *)->lock spinlock. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: move rcu lock out of ipc_addidDavidlohr Bueso2013-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patchset continues the work that began in the sysv ipc semaphore scaling series, see https://lkml.org/lkml/2013/3/20/546 Just like semaphores used to be, sysv shared memory and msg queues also abuse the ipc lock, unnecessarily holding it for operations such as permission and security checks. This patchset mostly deals with mqueues, and while shared mem can be done in a very similar way, I want to get these patches out in the open first. It also does some pending cleanups, mostly focused on the two level locking we have in ipc code, taking care of ipc_addid() and ipcctl_pre_down_nolock() - yes there are still functions that need to be updated as well. This patch: Make all callers explicitly take and release the RCU read lock. This addresses the two level locking seen in newary(), newseg() and newqueue(). For the last two, explicitly unlock the ipc object and the rcu lock, instead of calling the custom shm_unlock and msg_unlock functions. The next patch will deal with the open coded locking for ->perm.lock Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/shmc.c: eliminate ugly 80-col tricksAndrew Morton2013-07-09
| | | | | Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* audit: fix mq_open and mq_unlink to add the MQ root as a hidden parent ↵Jeff Layton2013-07-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | audit_names record The old audit PATH records for mq_open looked like this: type=PATH msg=audit(1366282323.982:869): item=1 name=(null) inode=6777 dev=00:0c mode=041777 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:tmpfs_t:s15:c0.c1023 type=PATH msg=audit(1366282323.982:869): item=0 name="test_mq" inode=26732 dev=00:0c mode=0100700 ouid=0 ogid=0 rdev=00:00 obj=staff_u:object_r:user_tmpfs_t:s15:c0.c1023 ...with the audit related changes that went into 3.7, they now look like this: type=PATH msg=audit(1366282236.776:3606): item=2 name=(null) inode=66655 dev=00:0c mode=0100700 ouid=0 ogid=0 rdev=00:00 obj=staff_u:object_r:user_tmpfs_t:s15:c0.c1023 type=PATH msg=audit(1366282236.776:3606): item=1 name=(null) inode=6926 dev=00:0c mode=041777 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:tmpfs_t:s15:c0.c1023 type=PATH msg=audit(1366282236.776:3606): item=0 name="test_mq" Both of these look wrong to me. As Steve Grubb pointed out: "What we need is 1 PATH record that identifies the MQ. The other PATH records probably should not be there." Fix it to record the mq root as a parent, and flag it such that it should be hidden from view when the names are logged, since the root of the mq filesystem isn't terribly interesting. With this change, we get a single PATH record that looks more like this: type=PATH msg=audit(1368021604.836:484): item=0 name="test_mq" inode=16914 dev=00:0c mode=0100644 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmpfs_t:s0 In order to do this, a new audit_inode_parent_hidden() function is added. If we do it this way, then we avoid having the existing callers of audit_inode needing to do any sort of flag conversion if auditing is inactive. Signed-off-by: Jeff Layton <jlayton@redhat.com> Reported-by: Jiri Jaburek <jjaburek@redhat.com> Cc: Steve Grubb <sgrubb@redhat.com> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc/sem.c: Fix missing wakeups in do_smart_update_queue()Manfred Spraul2013-05-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | do_smart_update_queue() is called when an operation (semop, semctl(SETVAL), semctl(SETALL), ...) modified the array. It must check which of the sleeping tasks can proceed. do_smart_update_queue() missed a few wakeups: - if a sleeping complex op was completed, then all per-semaphore queues must be scanned - not only those that were modified by *sops - if a sleeping simple op proceeded, then the global queue must be scanned again And: - the test for "|sops == NULL) before scanning the global queue is not required: If the global queue is empty, then it doesn't need to be scanned - regardless of the reason for calling do_smart_update_queue() The patch is not optimized, i.e. even completing a wait-for-zero operation causes a rescan. This is done to keep the patch as simple as possible. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* shm: fix null pointer deref when userspace specifies invalid hugepage sizeLi Zefan2013-05-09
| | | | | | | | | | | | | | | | | | | | | | | | | Dave reported an oops triggered by trinity: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: newseg+0x10d/0x390 PGD cf8c1067 PUD cf8c2067 PMD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC CPU: 2 PID: 7636 Comm: trinity-child2 Not tainted 3.9.0+#67 ... Call Trace: ipcget+0x182/0x380 SyS_shmget+0x5a/0x60 tracesys+0xdd/0xe2 This bug was introduced by commit af73e4d9506d ("hugetlbfs: fix mmap failure in unaligned size request"). Reported-by: Dave Jones <davej@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Li Zefan <lizfan@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,sem: fix semctl(..., GETNCNT)Rik van Riel2013-05-09
| | | | | | | | | | | | | The semctl GETNCNT returns the number of semops waiting for the specified semaphore to become nonzero. After commit 9f1bc2c9022c ("ipc,sem: have only one list in struct sem_queue"), the semops waiting on just one semaphore are waiting on that semaphore's list. In order to return the correct count, we have to walk that list too, in addition to the sem_array's list for complex operations. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc,sem: fix semctl(..., GETZCNT)Rik van Riel2013-05-09
| | | | | | | | | | | | | | | | | The semctl GETZCNT returns the number of semops waiting for the specified semaphore to become zero. After commit 9f1bc2c9022c ("ipc,sem: have only one list in struct sem_queue"), the semops waiting on just one semaphore are waiting on that semaphore's list. In order to return the correct count, we have to walk that list too, in addition to the sem_array's list for complex operations. This bug broke dbench; it works again with this patch applied. Signed-off-by: Rik van Riel <riel@redhat.com> Reported-by: Kent Overstreet <koverstreet@google.com> Tested-by: Kent Overstreet <koverstreet@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: fix mmap failure in unaligned size requestNaoya Horiguchi2013-05-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The current kernel returns -EINVAL unless a given mmap length is "almost" hugepage aligned. This is because in sys_mmap_pgoff() the given length is passed to vm_mmap_pgoff() as it is without being aligned with hugepage boundary. This is a regression introduced in commit 40716e29243d ("hugetlbfs: fix alignment of huge page requests"), where alignment code is pushed into hugetlb_file_setup() and the variable len in caller side is not changed. To fix this, this patch partially reverts that commit, and adds alignment code in caller side. And it also introduces hstate_sizelog() in order to get proper hstate to specified hugepage size. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=56881 [akpm@linux-foundation.org: fix warning when CONFIG_HUGETLB_PAGE=n] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: <iceman_dvd@yahoo.com> Cc: Steven Truelove <steven.truelove@utoronto.ca> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: simplify rcu_read_lock() in semctl_nolock()Linus Torvalds2013-05-04
| | | | | | | | | | | | This trivially combines two rcu_read_lock() calls in both sides of a if-statement into one single one in front of the if-statement. Split out as an independent cleanup from the previous commit. Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: simplify semtimedop/semctl_main() common error path handlingLinus Torvalds2013-05-04
| | | | | | | | | | | | | | | | | | | With various straight RCU lock/unlock movements, one common exit path pattern had become rcu_read_unlock(); goto out_wakeup; and in fact there were no cases where we wanted to exit to out_wakeup _without_ releasing the RCU read lock. So replace that pattern with "goto out_rcu_wakeup", and remove the old out_wakeup. Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: move sem_obtain_lock() rcu locking into the only callerLinus Torvalds2013-05-04
| | | | | | | | | | | | | | | | sem_obtain_lock() was another of those functions that returned with the RCU lock held for reading in the success case. Move the RCU locking to the caller (semtimedop()), making it more obvious. We already did RCU locking elsewhere in that function. Side note: why does semtimedop() re-do the semphore lookup after the sleep, rather than just getting a reference to the semaphore it already looked up originally? Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: fix double sem unlock in semctl error pathLinus Torvalds2013-05-04
| | | | | | | | | | | | | | | Fix another ipc locking buglet introduced by the scalability patches: when semctl_down() was changed to delay the semaphore locking, one error path for security_sem_semctl() went through the semaphore unlock logic even though the semaphore had never been locked. Introduced by commit 16df3674efe3 ("ipc,sem: do not hold ipc lock more than necessary") Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: move the rcu_read_lock() from sem_lock_and_putref() into callersLinus Torvalds2013-05-04
| | | | | | | | | | | | | | | | This is another ipc semaphore locking cleanup, trying to make the locking more straightforward. We move the rcu read locking into the callers of sem_lock_and_putref(), which in general means that we now mostly do the rcu_read_lock() and rcu_read_unlock() in the same function. Mostly. We still have the ipc_addid/newary/freeary mess, and things like ipcctl_pre_down_nolock(). Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: sem_putref() does not need the semaphore lock any moreLinus Torvalds2013-05-04
| | | | | | | | | | | ipc_rcu_putref() uses atomics for the refcount, and the games to lock and unlock the semaphore just to try to keep the reference counting working are no longer useful. Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: move rcu_read_unlock() out of sem_unlock() and into callersLinus Torvalds2013-05-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The IPC locking is a mess, and sem_unlock() unlocks not only the semaphore spinlock, it also drops the rcu read lock. Unlike sem_lock(), which just gets the spin-lock, and expects the caller to get the rcu read lock. This all makes things very hard to follow, and it's very confusing when you take the rcu read lock in one function, and then release it in another. And it has caused actual bugs: the sem_obtain_lock() function ended up dropping the RCU read lock twice in one error path, because it first did the sem_unlock(), and then did a rcu_read_unlock() to match the rcu_read_lock() it had done. This is just a totally mindless "remove rcu_read_unlock() from sem_unlock() and add it immediately after each caller" (except for the aforementioned bug where we did too many rcu_read_unlock(), and in find_alloc_undo() where we just got the rcu_read_lock() to correct for the fact that sem_unlock would immediately drop it again). We can (and should) clean things up further, but this fixes the bug with the minimal amount of subtlety. Reviewed-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc: fix GETALL/IPC_RM race for sysv semaphoresAl Viro2013-05-02
| | | | | | | | | | | | | | | We can step on WARN_ON_ONCE() in sem_getref() if a semaphore is removed just as we are about to call sem_getref() from semctl_main(); results are not pretty. We should fail with -EIDRM, same as if IPC_RM happened while we'd been doing allocation there. This also expands sem_getref() at its only callsite (and fixed there), while sem_getref_and_unlock() is simply killed off - it has no callers at all. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ipc_schedule_free() can do vfree() directly nowAl Viro2013-05-02
| | | | | | | | | | Commit 32fcfd40715e ("make vfree() safe to call from interrupt contexts") made it safe to do vfree directly from the RCU callback, which allows us to simplify ipc/util.c a lot by getting rid of the differences between vmalloc/kmalloc memory. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2013-05-01
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...
| * proc: Split the namespace stuff out into linux/proc_ns.hDavid Howells2013-05-01
| | | | | | | | | | | | | | | | | | | | Split the proc namespace stuff out into linux/proc_ns.h. Signed-off-by: David Howells <dhowells@redhat.com> cc: netdev@vger.kernel.org cc: Serge E. Hallyn <serge.hallyn@ubuntu.com> cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * procfs: new helper - PDE_DATA(inode)Al Viro2013-04-09
| | | | | | | | | | | | | | | | | | | | The only part of proc_dir_entry the code outside of fs/proc really cares about is PDE(inode)->data. Provide a helper for that; static inline for now, eventually will be moved to fs/proc, along with the knowledge of struct proc_dir_entry layout. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | ipc: sysv shared memory limited to 8TiBRobin Holt2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trying to run an application which was trying to put data into half of memory using shmget(), we found that having a shmall value below 8EiB-8TiB would prevent us from using anything more than 8TiB. By setting kernel.shmall greater than 8EiB-8TiB would make the job work. In the newseg() function, ns->shm_tot which, at 8TiB is INT_MAX. ipc/shm.c: 458 static int newseg(struct ipc_namespace *ns, struct ipc_params *params) 459 { ... 465 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; ... 474 if (ns->shm_tot + numpages > ns->shm_ctlall) 475 return -ENOSPC; [akpm@linux-foundation.org: make ipc/shm.c:newseg()'s numpages size_t, not int] Signed-off-by: Robin Holt <holt@sgi.com> Reported-by: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc/msg.c: use list_for_each_entry_[safe] for list traversingNikola Pajkovsky2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | The ipc/msg.c code does its list operations by hand and it open-codes the accesses, instead of using for_each_entry_[safe]. Signed-off-by: Nikola Pajkovsky <npajkovs@redhat.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc,sem: fine grained locking for semtimedopRik van Riel2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce finer grained locking for semtimedop, to handle the common case of a program wanting to manipulate one semaphore from an array with multiple semaphores. If the call is a semop manipulating just one semaphore in an array with multiple semaphores, only take the lock for that semaphore itself. If the call needs to manipulate multiple semaphores, or another caller is in a transaction that manipulates multiple semaphores, the sem_array lock is taken, as well as all the locks for the individual semaphores. On a 24 CPU system, performance numbers with the semop-multi test with N threads and N semaphores, look like this: vanilla Davidlohr's Davidlohr's + Davidlohr's + threads patches rwlock patches v3 patches 10 610652 726325 1783589 2142206 20 341570 365699 1520453 1977878 30 288102 307037 1498167 2037995 40 290714 305955 1612665 2256484 50 288620 312890 1733453 2650292 60 289987 306043 1649360 2388008 70 291298 306347 1723167 2717486 80 290948 305662 1729545 2763582 90 290996 306680 1736021 2757524 100 292243 306700 1773700 3059159 [davidlohr.bueso@hp.com: do not call sem_lock when bogus sma] [davidlohr.bueso@hp.com: make refcounter atomic] Signed-off-by: Rik van Riel <riel@redhat.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: Jason Low <jason.low2@hp.com> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Emmanuel Benisty <benisty.e@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc,sem: have only one list in struct sem_queueRik van Riel2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Having only one list in struct sem_queue, and only queueing simple semaphore operations on the list for the semaphore involved, allows us to introduce finer grained locking for semtimedop. Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: Emmanuel Benisty <benisty.e@gmail.com> Cc: Jason Low <jason.low2@hp.com> Cc: Michel Lespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc,sem: open code and rename sem_lockRik van Riel2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rename sem_lock() to sem_obtain_lock(), so we can introduce a sem_lock() later that only locks the sem_array and does nothing else. Open code the locking from ipc_lock() in sem_obtain_lock() so we can introduce finer grained locking for the sem_array in the next patch. [akpm@linux-foundation.org: propagate the ipc_obtain_object() errno out of sem_obtain_lock()] Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: Emmanuel Benisty <benisty.e@gmail.com> Cc: Jason Low <jason.low2@hp.com> Cc: Michel Lespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc,sem: do not hold ipc lock more than necessaryDavidlohr Bueso2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of holding the ipc lock for permissions and security checks, among others, only acquire it when necessary. Some numbers.... 1) With Rik's semop-multi.c microbenchmark we can see the following results: Baseline (3.9-rc1): cpus 4, threads: 256, semaphores: 128, test duration: 30 secs total operations: 151452270, ops/sec 5048409 + 59.40% a.out [kernel.kallsyms] [k] _raw_spin_lock + 6.14% a.out [kernel.kallsyms] [k] sys_semtimedop + 3.84% a.out [kernel.kallsyms] [k] avc_has_perm_flags + 3.64% a.out [kernel.kallsyms] [k] __audit_syscall_exit + 2.06% a.out [kernel.kallsyms] [k] copy_user_enhanced_fast_string + 1.86% a.out [kernel.kallsyms] [k] ipc_lock With this patchset: cpus 4, threads: 256, semaphores: 128, test duration: 30 secs total operations: 273156400, ops/sec 9105213 + 18.54% a.out [kernel.kallsyms] [k] _raw_spin_lock + 11.72% a.out [kernel.kallsyms] [k] sys_semtimedop + 7.70% a.out [kernel.kallsyms] [k] ipc_has_perm.isra.21 + 6.58% a.out [kernel.kallsyms] [k] avc_has_perm_flags + 6.54% a.out [kernel.kallsyms] [k] __audit_syscall_exit + 4.71% a.out [kernel.kallsyms] [k] ipc_obtain_object_check 2) While on an Oracle swingbench DSS (data mining) workload the improvements are not as exciting as with Rik's benchmark, we can see some positive numbers. For an 8 socket machine the following are the percentages of %sys time incurred in the ipc lock: Baseline (3.9-rc1): 100 swingbench users: 8,74% 400 swingbench users: 21,86% 800 swingbench users: 84,35% With this patchset: 100 swingbench users: 8,11% 400 swingbench users: 19,93% 800 swingbench users: 77,69% [riel@redhat.com: fix two locking bugs] [sasha.levin@oracle.com: prevent releasing RCU read lock twice in semctl_main] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Chegu Vinod <chegu_vinod@hp.com> Acked-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jason Low <jason.low2@hp.com> Cc: Emmanuel Benisty <benisty.e@gmail.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: introduce lockless pre_down ipcctlDavidlohr Bueso2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Various forms of ipc use ipcctl_pre_down() to retrieve an ipc object and check permissions, mostly for IPC_RMID and IPC_SET commands. Introduce ipcctl_pre_down_nolock(), a lockless version of this function. The locking version is retained, yet modified to call the nolock version without affecting its semantics, thus transparent to all ipc callers. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: Emmanuel Benisty <benisty.e@gmail.com> Cc: Jason Low <jason.low2@hp.com> Cc: Michel Lespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: introduce obtaining a lockless ipc objectDavidlohr Bueso2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Through ipc_lock() and therefore ipc_lock_check() we currently return the locked ipc object. This is not necessary for all situations and can, therefore, cause unnecessary ipc lock contention. Introduce analogous ipc_obtain_object() and ipc_obtain_object_check() functions that only lookup and return the ipc object. Both these functions must be called within the RCU read critical section. [akpm@linux-foundation.org: propagate the ipc_obtain_object() errno from ipc_lock()] Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Reviewed-by: Chegu Vinod <chegu_vinod@hp.com> Acked-by: Michel Lespinasse <walken@google.com> Cc: Emmanuel Benisty <benisty.e@gmail.com> Cc: Jason Low <jason.low2@hp.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: remove bogus lock comment for ipc_checkidDavidlohr Bueso2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This series makes the sysv semaphore code more scalable, by reducing the time the semaphore lock is held, and making the locking more scalable for semaphore arrays with multiple semaphores. The first four patches were written by Davidlohr Buesso, and reduce the hold time of the semaphore lock. The last three patches change the sysv semaphore code locking to be more fine grained, providing a performance boost when multiple semaphores in a semaphore array are being manipulated simultaneously. On a 24 CPU system, performance numbers with the semop-multi test with N threads and N semaphores, look like this: vanilla Davidlohr's Davidlohr's + Davidlohr's + threads patches rwlock patches v3 patches 10 610652 726325 1783589 2142206 20 341570 365699 1520453 1977878 30 288102 307037 1498167 2037995 40 290714 305955 1612665 2256484 50 288620 312890 1733453 2650292 60 289987 306043 1649360 2388008 70 291298 306347 1723167 2717486 80 290948 305662 1729545 2763582 90 290996 306680 1736021 2757524 100 292243 306700 1773700 3059159 This patch: There is no reason to be holding the ipc lock while reading ipcp->seq, hence remove misleading comment. Also simplify the return value for the function. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Chegu Vinod <chegu_vinod@hp.com> Cc: Emmanuel Benisty <benisty.e@gmail.com> Cc: Jason Low <jason.low2@hp.com> Cc: Michel Lespinasse <walken@google.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Stanislav Kinsbursky <skinsbursky@parallels.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc/msgutil.c: use linux/uaccess.hHoSung Jung2013-05-01
| | | | | | | | | | | | Signed-off-by: HoSung Jung <rain6557@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: refactor msg list search into separate functionPeter Hurley2013-05-01
| | | | | | | | | | | | | | | | [fengguang.wu@intel.com: find_msg can be static] Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: simplify msg list searchPeter Hurley2013-05-01
| | | | | | | | | | | | | | Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: implement MSG_COPY as a new receive modePeter Hurley2013-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | Teach the helper routines about MSG_COPY so that msgtyp is preserved as the message number to copy. The security functions affected by this change were audited and no additional changes are necessary. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | ipc: remove msg handling from queue scanPeter Hurley2013-05-01
| | | | | | | | | | | | | | | | | | | | In preparation for refactoring the queue scan into a separate function, relocate msg copying. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Stanislav Kinsbursky <skinsbursky@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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