{"push_id":1143553508,"size":4,"distinct_size":4,"ref":"refs/heads/cmatest","head":"ec253d36d6a90947dede05bab322c717f42d1c6e","before":"3884e24c6c83a84efd1904794a526810f40ec3e7","commits":[{"sha":"93578e08f96b2fd4f52e01634b3e926ac150bf48","author":{"name":"Dave Kleikamp","email":"24324fc4f213173a9791b5072d02e6f4a53085f5@oracle.com"},"message":"Asynchronous I/O latency to a solid-state disk greatly increased\nbetween the 2.6.32 and 3.0 kernels. By removing the plug from\ndo_io_submit(), we observed a 34% improvement in the I/O latency.\n\nUnfortunately, at this level, we don't know if the request is to\na rotating disk or not.\n\nSigned-off-by: Dan Trifan <jimsth@gmail.com>","distinct":true,"url":"https://api.github.com/repos/v01dz777/android_kernel_samsung_tuna_omap4/commits/93578e08f96b2fd4f52e01634b3e926ac150bf48"},{"sha":"bc696238c6c853dae16cc750965977cc3354a7dd","author":{"name":"Paul E. McKenney","email":"0e7edc073f39d0385f8433ab60979a97c480557c@linux.vnet.ibm.com"},"message":"fs/sync: Make sync() satisfy many requests with one invocation\n\nDave Jones reported RCU stalls, overly long hrtimer interrupts, and\namazingly long NMI handlers from a trinity-induced workload involving\nlots of concurrent sync() calls (https://lkml.org/lkml/2013/7/23/369).\nThere are any number of things that one might do to make sync() behave\nbetter under high levels of contention, but it is also the case that\nmultiple concurrent sync() system calls can be satisfied by a single\nsys_sync() invocation.\n\nGiven that this situation is reminiscent of rcu_barrier(), this commit\napplies the rcu_barrier() approach to sys_sync().  This approach uses\na global mutex and a sequence counter.  The mutex is held across the\nsync() operation, which eliminates contention between concurrent sync()\noperations.  The counter is incremented at the beginning and end of\neach sync() operation, so that it is odd while a sync() operation is in\nprogress and even otherwise, just like sequence locks.\n\nThe code that used to be in sys_sync() is now in do_sync(), and sys_sync()\nnow handles the concurrency.  The sys_sync() function first takes a\nsnapshot of the counter, then acquires the mutex, and then takes another\nsnapshot of the counter.  If the values of the two snapshots indicate that\na full do_sync() executed during the mutex acquisition, the sys_sync()\nfunction releases the mutex and returns (\"Our work is done!\").  Otherwise,\nsys_sync() increments the counter, invokes do_sync(), and increments\nthe counter again.\n\nThis approach allows a single call to do_sync() to satisfy an arbitrarily\nlarge number of sync() system calls, which should eliminate issues due\nto large numbers of concurrent invocations of the sync() system call.\n\nChanges since v1 (https://lkml.org/lkml/2013/7/24/683):\n\no\tAdd a pair of memory barriers to keep the increments from\n\tbleeding into the do_sync() code.  (The failure probability\n\tis insanely low, but when you have several hundred million\n\tdevices running Linux, you can expect several hundred instances\n\tof one-in-a-million failures.)\n\no\tActually CC some people who have experience in this area.\n\nReported-by: Dave Jones <davej@redhat.com>\nSigned-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>\nCc: Alexander Viro <viro@zeniv.linux.org.uk>\nCc: Christoph Hellwig <hch@lst.de>\nCc: Jan Kara <jack@suse.cz>\nCc: Curt Wohlgemuth <curtw@google.com>\nCc: Jens Axboe <jaxboe@fusionio.com>\nCc: linux-fsdevel@vger.kernel.org\n\nSigned-off-by: Paul Reioux <reioux@gmail.com>\nSigned-off-by: Dan Trifan <jimsth@gmail.com>","distinct":true,"url":"https://api.github.com/repos/v01dz777/android_kernel_samsung_tuna_omap4/commits/bc696238c6c853dae16cc750965977cc3354a7dd"},{"sha":"488c9d9e4642d9d7178ca0eb41c8ddbcb45d4ed4","author":{"name":"Ezekeel","email":"9529c6ce7729ba891eb4b9ea8706bc1a97c55357@googlemail.com"},"message":"Added FSync Control version 1.\n\nConflicts:\n\tdrivers/misc/Kconfig\n\tdrivers/misc/Makefile\n\nConflicts:\n\tfs/sync.c\n\nConflicts:\n\tdrivers/misc/Kconfig\n\tdrivers/misc/Makefile","distinct":true,"url":"https://api.github.com/repos/v01dz777/android_kernel_samsung_tuna_omap4/commits/488c9d9e4642d9d7178ca0eb41c8ddbcb45d4ed4"},{"sha":"ec253d36d6a90947dede05bab322c717f42d1c6e","author":{"name":"bsmitty83","email":"664cc6b6231867690d6fd56291268a7cdf670b1a@gmail.com"},"message":"Fsync Control : fix function decleration isnt a prototype error\ncaused by the last commit","distinct":true,"url":"https://api.github.com/repos/v01dz777/android_kernel_samsung_tuna_omap4/commits/ec253d36d6a90947dede05bab322c717f42d1c6e"}]}
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