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Hello. I would like to ask about having mysql data hosted on glusterfs. Please see my issue below. I have posted DEBUG log information on pastebin. I am using GlusterFS version: glusterfs 1.4.0rc7 FUSE Version :fuse-2.7.3glfs10 my ISSUE is: When hosting mysql data on glusterfs I have an issue: The first time I start the glusterfsd server using [root at mohan ~]#

...airlocks_enabled)) > + return queue_spin_trylock_unfair(lock); > + else > + return queue_spin_trylock(lock); > +} So I really don't see the point of all this? Why do you need special {try,}lock paths for this case? Are you worried about the upper 24bits? > diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c > index ae1b19d..3723c83 100644 > --- a/kernel/locking/qspinlock.c > +++ b/kernel/locking/qspinlock.c > @@ -217,6 +217,14 @@ static __always_inline int try_set_locked(struct qspinlock *lock) > { > struct __qspinlock *l = (void *)lock; &g...

...airlocks_enabled)) > + return queue_spin_trylock_unfair(lock); > + else > + return queue_spin_trylock(lock); > +} So I really don't see the point of all this? Why do you need special {try,}lock paths for this case? Are you worried about the upper 24bits? > diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c > index ae1b19d..3723c83 100644 > --- a/kernel/locking/qspinlock.c > +++ b/kernel/locking/qspinlock.c > @@ -217,6 +217,14 @@ static __always_inline int try_set_locked(struct qspinlock *lock) > { > struct __qspinlock *l = (void *)lock; &g...

...ed field which sits at different places in the two endianness > system. > > We override some arch_spin_XXX as powerpc has io_sync stuff which makes > sure the io operations are protected by the lock correctly. > > There is another special case, see commit > 2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more") > > Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> > --- > arch/powerpc/include/asm/qspinlock.h | 66 +++++++++++++++++++++++++++++++ > arch/powerpc/include/asm/spinlock.h | 31 +++++++++------ > a...

...ed field which sits at different places in the two endianness > system. > > We override some arch_spin_XXX as powerpc has io_sync stuff which makes > sure the io operations are protected by the lock correctly. > > There is another special case, see commit > 2c610022711 ("locking/qspinlock: Fix spin_unlock_wait() some more") > > Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> > --- > arch/powerpc/include/asm/qspinlock.h | 66 +++++++++++++++++++++++++++++++ > arch/powerpc/include/asm/spinlock.h | 31 +++++++++------ > a...

...uot;execute": "query-qmp-schema" }' '{ "execute": "quit" }' | "/usr/bin/qemu-system-x86_64" -display none -machine "accel=kvm:tcg" -qmp stdio libguestfs: saving test results libguestfs: qemu version: 2.10 libguestfs: qemu mandatory locking: yes libguestfs: trace: get_sockdir libguestfs: trace: get_sockdir = "/tmp" libguestfs: finished testing qemu features libguestfs: trace: get_backend_setting "gdb" libguestfs: trace: get_backend_setting = NULL (error) libguestfs: command: run: dmesg | grep -Eoh 'lpj=[[:digit...

From: Jeremy Fitzhardinge <jeremy.fitzhardinge at citrix.com> Hi all, This is a revised version of the pvticket lock series. The early part of the series is mostly unchanged: it converts the bulk of the ticket lock code into C and makes the "small" and "large" ticket code common. The only changes are the incorporation of various review comments. The latter part of

From: Jeremy Fitzhardinge <jeremy.fitzhardinge at citrix.com> Hi all, This is a revised version of the pvticket lock series. The early part of the series is mostly unchanged: it converts the bulk of the ticket lock code into C and makes the "small" and "large" ticket code common. The only changes are the incorporation of various review comments. The latter part of

From: Jeremy Fitzhardinge <jeremy.fitzhardinge at citrix.com> Hi all, This is a revised version of the pvticket lock series. The early part of the series is mostly unchanged: it converts the bulk of the ticket lock code into C and makes the "small" and "large" ticket code common. The only changes are the incorporation of various review comments. The latter part of

To prepare for queued spinlocks. This is a simple rename except to update preprocessor guard name and a file reference. Signed-off-by: Nicholas Piggin <npiggin at gmail.com> --- arch/powerpc/include/asm/simple_spinlock.h | 292 ++++++++++++++++++ .../include/asm/simple_spinlock_types.h | 21 ++ arch/powerpc/include/asm/spinlock.h | 285 +----------------

On 12/03/14 18:54, Waiman Long wrote: > Locking is always an issue in a virtualized environment as the virtual > CPU that is waiting on a lock may get scheduled out and hence block > any progress in lock acquisition even when the lock has been freed. > > One solution to this problem is to allow unfair lock in a > para-virtualized...

On 12/03/14 18:54, Waiman Long wrote: > Locking is always an issue in a virtualized environment as the virtual > CPU that is waiting on a lock may get scheduled out and hence block > any progress in lock acquisition even when the lock has been freed. > > One solution to this problem is to allow unfair lock in a > para-virtualized...

...the normal unlock, and then checks to see if it needs to do a special "kick" to wake the next CPU. The net result is that the pv-op calls are restricted to the slow paths, and the normal fast-paths are largely unaffected. There are still some overheads, however: - When locking, there's some extra tests to count the spin iterations. There are no extra instructions in the uncontended case though. - When unlocking, there are two ways to detect when it is necessary to kick a blocked CPU: - with an unmodified struct spinlock, it can check to see if...

...the normal unlock, and then checks to see if it needs to do a special "kick" to wake the next CPU. The net result is that the pv-op calls are restricted to the slow paths, and the normal fast-paths are largely unaffected. There are still some overheads, however: - When locking, there's some extra tests to count the spin iterations. There are no extra instructions in the uncontended case though. - When unlocking, there are two ways to detect when it is necessary to kick a blocked CPU: - with an unmodified struct spinlock, it can check to see if...

...the normal unlock, and then checks to see if it needs to do a special "kick" to wake the next CPU. The net result is that the pv-op calls are restricted to the slow paths, and the normal fast-paths are largely unaffected. There are still some overheads, however: - When locking, there's some extra tests to count the spin iterations. There are no extra instructions in the uncontended case though. - When unlocking, there are two ways to detect when it is necessary to kick a blocked CPU: - with an unmodified struct spinlock, it can check to see if...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG)) __ticket_unlock_slowpath(lock, prev); which

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG)) __ticket_unlock_slowpath(lock, prev); which

...ion. - Add an optimized x86 code path for 2 contending tasks to improve low contention performance. v2->v3: - Simplify the code by using numerous mode only without an unfair option. - Use the latest smp_load_acquire()/smp_store_release() barriers. - Move the queue spinlock code to kernel/locking. - Make the use of queue spinlock the default for x86-64 without user configuration. - Additional performance tuning. v1->v2: - Add some more comments to document what the code does. - Add a numerous CPU mode to support >= 16K CPUs - Add a configuration option to allow lock stealing...

...ion. - Add an optimized x86 code path for 2 contending tasks to improve low contention performance. v2->v3: - Simplify the code by using numerous mode only without an unfair option. - Use the latest smp_load_acquire()/smp_store_release() barriers. - Move the queue spinlock code to kernel/locking. - Make the use of queue spinlock the default for x86-64 without user configuration. - Additional performance tuning. v1->v2: - Add some more comments to document what the code does. - Add a numerous CPU mode to support >= 16K CPUs - Add a configuration option to allow lock stealing...

...ion. - Add an optimized x86 code path for 2 contending tasks to improve low contention performance. v2->v3: - Simplify the code by using numerous mode only without an unfair option. - Use the latest smp_load_acquire()/smp_store_release() barriers. - Move the queue spinlock code to kernel/locking. - Make the use of queue spinlock the default for x86-64 without user configuration. - Additional performance tuning. v1->v2: - Add some more comments to document what the code does. - Add a numerous CPU mode to support >= 16K CPUs - Add a configuration option to allow lock stealing...