# git rev-parse -q --verify 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b^{commit} 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b already have revision, skipping fetch # git checkout -q -f -B kisskb 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b # git clean -qxdf # < git log -1 # commit 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b # Merge: 80201fe175cb 21b4aa5d20fd # Author: Linus Torvalds # Date: Fri Mar 8 14:48:40 2019 -0800 # # Merge tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block # # Pull io_uring IO interface from Jens Axboe: # "Second attempt at adding the io_uring interface. # # Since the first one, we've added basic unit testing of the three # system calls, that resides in liburing like the other unit tests that # we have so far. It'll take a while to get full coverage of it, but # we're working towards it. I've also added two basic test programs to # tools/io_uring. One uses the raw interface and has support for all the # various features that io_uring supports outside of standard IO, like # fixed files, fixed IO buffers, and polled IO. The other uses the # liburing API, and is a simplified version of cp(1). # # This adds support for a new IO interface, io_uring. # # io_uring allows an application to communicate with the kernel through # two rings, the submission queue (SQ) and completion queue (CQ) ring. # This allows for very efficient handling of IOs, see the v5 posting for # some basic numbers: # # https://lore.kernel.org/linux-block/20190116175003.17880-1-axboe@kernel.dk/ # # Outside of just efficiency, the interface is also flexible and # extendable, and allows for future use cases like the upcoming NVMe # key-value store API, networked IO, and so on. It also supports async # buffered IO, something that we've always failed to support in the # kernel. # # Outside of basic IO features, it supports async polled IO as well. # This particular feature has already been tested at Facebook months ago # for flash storage boxes, with 25-33% improvements. It makes polled IO # actually useful for real world use cases, where even basic flash sees # a nice win in terms of efficiency, latency, and performance. These # boxes were IOPS bound before, now they are not. # # This series adds three new system calls. One for setting up an # io_uring instance (io_uring_setup(2)), one for submitting/completing # IO (io_uring_enter(2)), and one for aux functions like registrating # file sets, buffers, etc (io_uring_register(2)). Through the help of # Arnd, I've coordinated the syscall numbers so merge on that front # should be painless. # # Jon did a writeup of the interface a while back, which (except for # minor details that have been tweaked) is still accurate. Find that # here: # # https://lwn.net/Articles/776703/ # # Huge thanks to Al Viro for helping getting the reference cycle code # correct, and to Jann Horn for his extensive reviews focused on both # security and bugs in general. # # There's a userspace library that provides basic functionality for # applications that don't need or want to care about how to fiddle with # the rings directly. It has helpers to allow applications to easily set # up an io_uring instance, and submit/complete IO through it without # knowing about the intricacies of the rings. It also includes man pages # (thanks to Jeff Moyer), and will continue to grow support helper # functions and features as time progresses. Find it here: # # git://git.kernel.dk/liburing # # Fio has full support for the raw interface, both in the form of an IO # engine (io_uring), but also with a small test application (t/io_uring) # that can exercise and benchmark the interface" # # * tag 'io_uring-2019-03-06' of git://git.kernel.dk/linux-block: # io_uring: add a few test tools # io_uring: allow workqueue item to handle multiple buffered requests # io_uring: add support for IORING_OP_POLL # io_uring: add io_kiocb ref count # io_uring: add submission polling # io_uring: add file set registration # net: split out functions related to registering inflight socket files # io_uring: add support for pre-mapped user IO buffers # block: implement bio helper to add iter bvec pages to bio # io_uring: batch io_kiocb allocation # io_uring: use fget/fput_many() for file references # fs: add fget_many() and fput_many() # io_uring: support for IO polling # io_uring: add fsync support # Add io_uring IO interface # < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 38e7571c07be01f9f19b355a9306a4e3d5cb0f5b # < make -s -j 48 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 defconfig # make -s -j 48 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 /kisskb/src/arch/um/kernel/skas/uaccess.c: In function 'do_op_one_page': /kisskb/src/arch/um/kernel/skas/uaccess.c:62:10: warning: unused variable 'buf' [-Wunused-variable] jmp_buf buf; ^ /kisskb/src/arch/um/os-Linux/umid.c: In function 'is_umdir_used': /kisskb/src/arch/um/os-Linux/umid.c:138:2: warning: ISO C90 forbids variable length array 'file' [-Wvla] char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")]; ^ /kisskb/src/arch/um/os-Linux/umid.c: In function 'create_pid_file': /kisskb/src/arch/um/os-Linux/umid.c:213:2: warning: ISO C90 forbids variable length array 'file' [-Wvla] char file[strlen(uml_dir) + UMID_LEN + sizeof("/pid\0")]; ^ /kisskb/src/arch/um/os-Linux/umid.c: In function 'remove_umid_dir': /kisskb/src/arch/um/os-Linux/umid.c:388:2: warning: ISO C90 forbids variable length array 'dir' [-Wvla] char dir[strlen(uml_dir) + UMID_LEN + 1], err; ^ /kisskb/src/mm/mprotect.c: In function 'change_pte_range': /kisskb/src/mm/mprotect.c:42:20: warning: unused variable 'mm' [-Wunused-variable] struct mm_struct *mm = vma->vm_mm; ^ LINK linux Completed OK # rm -rf /kisskb/build/linus_um-defconfig_um-x86_64 # Build took: 0:00:37.279156