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* Linux compat: Minimum kernel version 3.10Brian Behlendorf2019-11-121-30/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Increase the minimum supported kernel version from 2.6.32 to 3.10. This removes support for the following Linux enterprise distributions. Distribution | Kernel | End of Life ---------------- | ------ | ------------- Ubuntu 12.04 LTS | 3.2 | Apr 28, 2017 SLES 11 | 3.0 | Mar 32, 2019 RHEL / CentOS 6 | 2.6.32 | Nov 30, 2020 The following changes were made as part of removing support. * Updated `configure` to enforce a minimum kernel version as specified in the META file (Linux-Minimum: 3.10). configure: error: *** Cannot build against kernel version 2.6.32. *** The minimum supported kernel version is 3.10. * Removed all `configure` kABI checks and matching C code for interfaces which solely predate the Linux 3.10 kernel. * Updated all `configure` kABI checks to fail when an interface is missing which was in the 3.10 kernel up to the latest 5.1 kernel. Removed the HAVE_* preprocessor defines for these checks and updated the code to unconditionally use the verified interface. * Inverted the detection logic in several kABI checks to match the new interface as it appears in 3.10 and newer and not the legacy interface. * Consolidated the following checks in to individual files. Due the large number of changes in the checks it made sense to handle this now. It would be desirable to group other related checks in the same fashion, but this as left as future work. - config/kernel-blkdev.m4 - Block device kABI checks - config/kernel-blk-queue.m4 - Block queue kABI checks - config/kernel-bio.m4 - Bio interface kABI checks * Removed the kABI checks for sops->nr_cached_objects() and sops->free_cached_objects(). These interfaces are currently unused. Signed-off-by: Brian Behlendorf <[email protected]> Closes #9566
* Perform KABI checks in parallelBrian Behlendorf2019-10-011-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reduce the time required for ./configure to perform the needed KABI checks by allowing kbuild to compile multiple test cases in parallel. This was accomplished by splitting each test's source code from the logic handling whether that code could be compiled or not. By introducing this split it's possible to minimize the number of times kbuild needs to be invoked. As importantly, it means all of the tests can be built in parallel. This does require a little extra care since we expect some tests to fail, so the --keep-going (-k) option must be provided otherwise some tests may not get compiled. Furthermore, since a failure during the kbuild modpost phase will result in an early exit; the final linking phase is limited to tests which passed the initial compilation and produced an object file. Once everything has been built the configure script proceeds as previously. The only significant difference is that it now merely needs to test for the existence of a .ko file to determine the result of a given test. This vastly speeds up the entire process. New test cases should use ZFS_LINUX_TEST_SRC to declare their test source code and ZFS_LINUX_TEST_RESULT to check the result. All of the existing kernel-*.m4 files have been updated accordingly, see config/kernel-current-time.m4 for a basic example. The legacy ZFS_LINUX_TRY_COMPILE macro has been kept to handle special cases but it's use is not encouraged. master (secs) patched (secs) ------------- ---------------- autogen.sh 61 68 configure 137 24 (~17% of current run time) make -j $(nproc) 44 44 make rpms 287 150 Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #8547 Closes #9132 Closes #9341
* zvol processing should use struct bioRichard Yao2015-09-041-0/+25
Internally, zvols are files exposed through the block device API. This is intended to reduce overhead when things require block devices. However, the ZoL zvol code emulates a traditional block device in that it has a top half and a bottom half. This is an unnecessary source of overhead that does not exist on any other OpenZFS platform does this. This patch removes it. Early users of this patch reported double digit performance gains in IOPS on zvols in the range of 50% to 80%. Comments in the code suggest that the current implementation was done to obtain IO merging from Linux's IO elevator. However, the DMU already does write merging while arc_read() should implicitly merge read IOs because only 1 thread is permitted to fetch the buffer into ARC. In addition, commercial ZFSOnLinux distributions report that regular files are more performant than zvols under the current implementation, and the main consumers of zvols are VMs and iSCSI targets, which have their own elevators to merge IOs. Some minor refactoring allows us to register zfs_request() as our ->make_request() handler in place of the generic_make_request() function. This eliminates the layer of code that broke IO requests on zvols into a top half and a bottom half. This has several benefits: 1. No per zvol spinlocks. 2. No redundant IO elevator processing. 3. Interrupts are disabled only when actually necessary. 4. No redispatching of IOs when all taskq threads are busy. 5. Linux's page out routines will properly block. 6. Many autotools checks become obsolete. An unfortunate consequence of eliminating the layer that generic_make_request() is that we no longer calls the instrumentation hooks for block IO accounting. Those hooks are GPL-exported, so we cannot call them ourselves and consequently, we lose the ability to do IO monitoring via iostat. Since zvols are internally files mapped as block devices, this should be okay. Anyone who is willing to accept the performance penalty for the block IO layer's accounting could use the loop device in between the zvol and its consumer. Alternatively, perf and ftrace likely could be used. Also, tools like latencytop will still work. Tools such as latencytop sometimes provide a better view of performance bottlenecks than the traditional block IO accounting tools do. Lastly, if direct reclaim occurs during spacemap loading and swap is on a zvol, this code will deadlock. That deadlock could already occur with sync=always on zvols. Given that swap on zvols is not yet production ready, this is not a blocker. Signed-off-by: Richard Yao <[email protected]>