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mirror_zfs/config/kernel-discard-granularity.m4

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Set zvol discard_granularity to the volblocksize. Currently, zvols have a discard granularity set to 0, which suggests to the upper layer that discard requests of arbirarily small size and alignment can be made efficiently. In practice however, ZFS does not handle unaligned discard requests efficiently: indeed, it is unable to free a part of a block. It will write zeros to the specified range instead, which is both useless and inefficient (see dnode_free_range). With this patch, zvol block devices expose volblocksize as their discard granularity, so the upper layer is aware that it's not supposed to send discard requests smaller than volblocksize. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #862
2012-08-01 12:29:59 +04:00
dnl #
dnl # 2.6.33 API change
dnl # Discard granularity and alignment restrictions may now be set.
dnl #
Perform KABI checks in parallel 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 <hutter2@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #8547 Closes #9132 Closes #9341 Conflicts: Makefile.am config/kernel-fpu.m4
2019-10-01 22:50:34 +03:00
AC_DEFUN([ZFS_AC_KERNEL_SRC_DISCARD_GRANULARITY], [
ZFS_LINUX_TEST_SRC([discard_granularity], [
Set zvol discard_granularity to the volblocksize. Currently, zvols have a discard granularity set to 0, which suggests to the upper layer that discard requests of arbirarily small size and alignment can be made efficiently. In practice however, ZFS does not handle unaligned discard requests efficiently: indeed, it is unable to free a part of a block. It will write zeros to the specified range instead, which is both useless and inefficient (see dnode_free_range). With this patch, zvol block devices expose volblocksize as their discard granularity, so the upper layer is aware that it's not supposed to send discard requests smaller than volblocksize. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #862
2012-08-01 12:29:59 +04:00
#include <linux/blkdev.h>
],[
struct queue_limits ql __attribute__ ((unused));
ql.discard_granularity = 0;
Perform KABI checks in parallel 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 <hutter2@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #8547 Closes #9132 Closes #9341 Conflicts: Makefile.am config/kernel-fpu.m4
2019-10-01 22:50:34 +03:00
])
])
AC_DEFUN([ZFS_AC_KERNEL_DISCARD_GRANULARITY], [
AC_MSG_CHECKING([whether ql->discard_granularity is available])
ZFS_LINUX_TEST_RESULT([discard_granularity], [
Set zvol discard_granularity to the volblocksize. Currently, zvols have a discard granularity set to 0, which suggests to the upper layer that discard requests of arbirarily small size and alignment can be made efficiently. In practice however, ZFS does not handle unaligned discard requests efficiently: indeed, it is unable to free a part of a block. It will write zeros to the specified range instead, which is both useless and inefficient (see dnode_free_range). With this patch, zvol block devices expose volblocksize as their discard granularity, so the upper layer is aware that it's not supposed to send discard requests smaller than volblocksize. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #862
2012-08-01 12:29:59 +04:00
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_DISCARD_GRANULARITY, 1,
Perform KABI checks in parallel 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 <hutter2@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #8547 Closes #9132 Closes #9341 Conflicts: Makefile.am config/kernel-fpu.m4
2019-10-01 22:50:34 +03:00
[ql->discard_granularity is available])
Set zvol discard_granularity to the volblocksize. Currently, zvols have a discard granularity set to 0, which suggests to the upper layer that discard requests of arbirarily small size and alignment can be made efficiently. In practice however, ZFS does not handle unaligned discard requests efficiently: indeed, it is unable to free a part of a block. It will write zeros to the specified range instead, which is both useless and inefficient (see dnode_free_range). With this patch, zvol block devices expose volblocksize as their discard granularity, so the upper layer is aware that it's not supposed to send discard requests smaller than volblocksize. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #862
2012-08-01 12:29:59 +04:00
],[
AC_MSG_RESULT(no)
])
])
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