- 09 Jul, 2013 40 commits
-
-
Manfred Spraul authored
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>
-
Manfred Spraul authored
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 authored
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 authored
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 authored
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 authored
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:
-
Davidlohr Bueso authored
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:
-
Davidlohr Bueso authored
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:
Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by:
-
Davidlohr Bueso authored
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 authored
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 authored
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 authored
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 authored
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 authored
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 authored
Signed-off-by:
-
Davidlohr Bueso authored
Simple helpers around the (kern_ipc_perm *)->lock spinlock. Signed-off-by:
-
Davidlohr Bueso authored
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:
-
Andrew Morton authored
Signed-off-by:
-
Oleg Nesterov authored
flush_ptrace_hw_breakpoint() destroys the counters set by ptrace, but "leaks" ->debugreg6 and ->ptrace_dr7. The problem is minor, but still it doesn't look right and flush_thread() did this until commit 66cb5917 ("hw-breakpoints: use the new wrapper routines to access debug registers in process/thread code"). Now that PTRACE_DETACH does flush_ too this makes even more sense. Signed-off-by:
Oleg Nesterov <oleg@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by:
-
Oleg Nesterov authored
Change ptrace_detach() to call flush_ptrace_hw_breakpoint(child). This frees the slots for non-ptrace PERF_TYPE_BREAKPOINT users, and this ensures that the tracee won't be killed by SIGTRAP triggered by the active breakpoints. Test-case: unsigned long encode_dr7(int drnum, int enable, unsigned int type, unsigned int len) { unsigned long dr7; dr7 = ((len | type) & 0xf) << (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE); if (enable) dr7 |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)); return dr7; } int write_dr(int pid, int dr, unsigned long val) { return ptrace(PTRACE_POKEUSER, pid, offsetof (struct user, u_debugreg[dr]), val); } void func(void) { } int main(void) { int pid, stat; unsigned long dr7; pid = fork(); if (!pid) { assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0); kill(getpid(), SIGHUP); func(); return 0x13; } assert(pid == waitpid(-1, &stat, 0)); assert(WSTOPSIG(stat) == SIGHUP); assert(write_dr(pid, 0, (long)func) == 0); dr7 = encode_dr7(0, 1, DR_RW_EXECUTE, DR_LEN_1); assert(write_dr(pid, 7, dr7) == 0); assert(ptrace(PTRACE_DETACH, pid, 0,0) == 0); assert(pid == waitpid(-1, &stat, 0)); assert(stat == 0x1300); return 0; } Before this patch the child is killed after PTRACE_DETACH. Signed-off-by:Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by:
-
Oleg Nesterov authored
ptrace_set_debugreg() is trivial but looks horrible. Kill the unnecessary goto's and return's to cleanup the code. This matches ptrace_get_debugreg() which also needs the trivial whitespace cleanups. Signed-off-by:
-
Oleg Nesterov authored
Commit 24f1e32c ("hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events") introduced the minor regression. Before this commit PTRACE_POKEUSER DR7, enableDR0 PTRACE_POKEUSER DR0, address was perfectly valid, now PTRACE_POKEUSER(DR7) fails if DR0 was not previously initialized by PTRACE_POKEUSER(DR0). Change ptrace_write_dr7() to do ptrace_register_breakpoint(addr => 0) if !bp && !disabled. This fixes watchpoint-zeroaddr from ptrace-tests, see https://bugzilla.redhat.com/show_bug.cgi?id=660204. Signed-off-by:
Jan Kratochvil <jan.kratochvil@redhat.com> Acked-by:
-
Oleg Nesterov authored
No functional changes, preparation. Extract the "register breakpoint" code from ptrace_get_debugreg() into the new/generic helper, ptrace_register_breakpoint(). It will have more users. The patch also adds another simple helper, ptrace_fill_bp_fields(), to factor out the arch_bp_generic_fields() logic in register/modify. Signed-off-by:
-
Oleg Nesterov authored
ptrace_write_dr7() skips ptrace_modify_breakpoint(disabled => true) unless second_pass, this buys nothing but complicates the code and means that we always do the main loop twice even if "disabled" was never true. The comment says: Don't unregister the breakpoints right-away, unless all register_user_hw_breakpoint() requests have succeeded. Firstly, we do not do register_user_hw_breakpoint(), it was removed by commit 24f1e32c ("hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events"). We are going to restore register_user_hw_breakpoint() (see the next patch) but this doesn't matter: after commit 44234adc ("hw-breakpoints: Modify breakpoints without unregistering them") perf_event_disable() can not hurt, hw_breakpoint_del() does not free the slot. Remove the "second_pass" check from the main loop and simplify the code. Since we have to check "bp != NULL" anyway, the patch also removes the same check in ptrace_modify_breakpoint() and moves the comment into ptrace_write_dr7(). With this patch the second pass is only needed to restore the saved old_dr7. This should never fail, so the patch adds WARN_ON() to catch the potential problems as Frederic suggested. Signed-off-by:
-
Oleg Nesterov authored
ptrace_write_dr7() looks unnecessarily overcomplicated. We can factor out ptrace_modify_breakpoint() and do not do "continue" twice, just we need to pass the proper "disabled" argument to ptrace_modify_breakpoint(). Signed-off-by:
-
Oleg Nesterov authored
This reverts commit bf26c018 ("Prepare to fix racy accesses on task breakpoints"). The patch was fine but we can no longer race with SIGKILL after commit 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. Now that ptrace_get_breakpoints/ptrace_put_breakpoints have no callers, we can kill them and remove task->ptrace_bp_refcnt. Signed-off-by:
Michael Neuling <mikey@neuling.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by:
-
Oleg Nesterov authored
This reverts commit e0ac8457 ("hw_breakpoints: Fix racy access to ptrace breakpoints"). The patch was fine but we can no longer race with SIGKILL after commit 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. Signed-off-by:
-
Oleg Nesterov authored
This reverts commit bf0b8f4b ("hw_breakpoints: Fix racy access to ptrace breakpoints"). The patch was fine but we can no longer race with SIGKILL after commit 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. Signed-off-by:
Will Deacon <will.deacon@arm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by:
-
Oleg Nesterov authored
This reverts commit 07fa7a0a ("hw_breakpoints: Fix racy access to ptrace breakpoints") and removes ptrace_get/put_breakpoints() added by other commits. The patch was fine but we can no longer race with SIGKILL after commit 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. Signed-off-by:
-
Oleg Nesterov authored
This reverts commit 87dc669b ("hw_breakpoints: Fix racy access to ptrace breakpoints"). The patch was fine but we can no longer race with SIGKILL after commit 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. The patch only removes ptrace_get_breakpoints/ptrace_put_breakpoints and does a couple of "while at it" cleanups, it doesn't remove other changes from the reverted commit. Signed-off-by:
Ingo Molnar <mingo@kernel.org> Acked-by:
-
Mike Lockwood authored
This patch, originally from Android kernel, adds vfat ioctl command FAT_IOCTL_GET_VOLUME_ID, with this command we can get the vfat volume ID using following code: ioctl(fd, FAT_IOCTL_GET_VOLUME_ID, &volume_ID) This patch is a modified version of the patch by Mike Lockwood, with changes from Dmitry Pervushin, who noticed the original patch makes some volume IDs abiguous with error returns: for example, if volume id is 0xFFFFFDAD, that matches -ENOIOCTLCMD, we get "FFFFFFFF" from the user space. So add a parameter to ioctl to get the correct volume ID. Android uses vfat volume ID to identify different sd card, when a new sd card is inserted to device, android can scan the media on it and pop up new contents. Signed-off-by:
Bintian Wang <bintian.wang@linaro.org> Cc: dmitry pervushin <dpervushin@gmail.com> Cc: Mike Lockwood <lockwood@android.com> Cc: Colin Cross <ccross@android.com> Acked-by:
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: John Stultz <john.stultz@linaro.org> Cc: Sean McNeil <sean@mcneil.com> Signed-off-by:
-
Fabio Estevam authored
stmp_reset_block() may fail, so let's check its return value and propagate it in the case of error. Signed-off-by:
Fabio Estevam <fabio.estevam@freescale.com> Acked-by:
Shawn Guo <shawn.guo@linaro.org> Signed-off-by:
-
Wei Yongjun authored
Fix to return -EINVAL from the option parse error handling case instead of 0, as done elsewhere in this function. Signed-off-by:
Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: Petr Vandrovec <petr@vandrovec.name> Signed-off-by:
-
Joe Perches authored
Might as well check include timestamps and cache the include file CamelCase uses for the non-git case too. The camelcase cache file is now named: for git: .checkpatch-camelcase.git.<commit_id> for non-git: .checkpatch-camelcase.date.<YYYYMMDDhhmm> All .checkpatch-camelcase* files are deleted if not current. Signed-off-by:
Joe Perches <joe@perches.com> Signed-off-by:
-
Alex Thorlton authored
Add the cpu/pid that called WARN() so that the stack traces can be matched up with the WARNING messages. [akpm@linux-foundation.org: remove stray quote] Signed-off-by:
Alex Thorlton <athorlton@sgi.com> Reviewed-by:
Robin Holt <holt@sgi.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Vikram Mulukutla <markivx@codeaurora.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <tj@kernel.org> Signed-off-by:
-
Toshi Kani authored
online_pages() is called from memory_block_action() when a user requests to online a memory block via sysfs. This function needs to return a proper error value in case of error. Signed-off-by:
Toshi Kani <toshi.kani@hp.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Signed-off-by:
-
Michal Hocko authored
min_free_kbytes is updated during memory hotplug (by init_per_zone_wmark_min) currently which is right thing to do in most cases but this could be unexpected if admin increased the value to prevent from allocation failures and the new min_free_kbytes would be decreased as a result of memory hotadd. This patch saves the user defined value and allows updating min_free_kbytes only if it is higher than the saved one. A warning is printed when the new value is ignored. Signed-off-by:
Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Acked-by:
Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
-
Li Zefan authored
Now memcg has the same life cycle with its corresponding cgroup, and a cgroup is freed via RCU and then mem_cgroup_css_free() will be called in a work function, so we can simply call __mem_cgroup_free() in mem_cgroup_css_free(). This actually reverts commit 59927fb9 ("memcg: free mem_cgroup by RCU to fix oops"). Signed-off-by:
Li Zefan <lizefan@huawei.com> Cc: Hugh Dickins <hughd@google.com> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Glauber Costa <glommer@openvz.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
-
Li Zefan authored
Now memcg has the same life cycle as its corresponding cgroup. Kill the useless refcnt. Signed-off-by:
-
Li Zefan authored
The cgroup core guarantees it's always safe to access the parent. Signed-off-by:
-
