December 2023 - Linux-kselftest-mirror

[PATCH v6] lib: add basic KUnit test for lib/math

by Daniel Latypov

Add basic test coverage for files that don't require any config options: * part of math.h (what seem to be the most commonly used macros) * gcd.c * lcm.c * int_sqrt.c * reciprocal_div.c (Ignored int_pow.c since it's a simple textbook algorithm.) These tests aren't particularly interesting, but they * provide short and simple examples of parameterized tests * provide a place to add tests for any new files in this dir * are written so adding new test cases to cover edge cases should be easy * looking at code coverage, we hit all the branches in the .c files Signed-off-by: Daniel Latypov <dlatypov(a)google.com> Reviewed-by: David Gow <davidgow(a)google.com> --- Changes since v5: * add in test cases for roundup/rounddown * address misc comments from David Changes since v4: * add in test cases for some math.h macros (abs, round_up/round_down, div_round_down/closest) * use parameterized testing less to keep things terser Changes since v3: * fix `checkpatch.pl --strict` warnings * add test cases for gcd(0,0) and lcm(0,0) * minor: don't test both gcd(a,b) and gcd(b,a) when a == b Changes since v2: mv math_test.c => math_kunit.c Changes since v1: * Rebase and rewrite to use the new parameterized testing support. * misc: fix overflow in literal and inline int_sqrt format string. * related: commit 1f0e943df68a ("Documentation: kunit: provide guidance for testing many inputs") was merged explaining the patterns shown here. * there's an in-flight patch to update it for parameterized testing. --- lib/math/Kconfig | 12 ++ lib/math/Makefile | 2 + lib/math/math_kunit.c | 291 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 305 insertions(+) create mode 100644 lib/math/math_kunit.c diff --git a/lib/math/Kconfig b/lib/math/Kconfig index f19bc9734fa7..a974d4db0f9c 100644 --- a/lib/math/Kconfig +++ b/lib/math/Kconfig @@ -15,3 +15,15 @@ config PRIME_NUMBERS config RATIONAL bool + +config MATH_KUNIT_TEST + tristate "KUnit test for lib/math and math.h" if !KUNIT_ALL_TESTS + depends on KUNIT + default KUNIT_ALL_TESTS + help + This builds unit tests for lib/math and math.h. + + For more information on KUnit and unit tests in general, please refer + to the KUnit documentation in Documentation/dev-tools/kunit/. + + If unsure, say N. diff --git a/lib/math/Makefile b/lib/math/Makefile index be6909e943bd..30abb7a8d564 100644 --- a/lib/math/Makefile +++ b/lib/math/Makefile @@ -4,3 +4,5 @@ obj-y += div64.o gcd.o lcm.o int_pow.o int_sqrt.o reciprocal_div.o obj-$(CONFIG_CORDIC) += cordic.o obj-$(CONFIG_PRIME_NUMBERS) += prime_numbers.o obj-$(CONFIG_RATIONAL) += rational.o + +obj-$(CONFIG_MATH_KUNIT_TEST) += math_kunit.o diff --git a/lib/math/math_kunit.c b/lib/math/math_kunit.c new file mode 100644 index 000000000000..556c23b17c3c --- /dev/null +++ b/lib/math/math_kunit.c @@ -0,0 +1,291 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Simple KUnit suite for math helper funcs that are always enabled. + * + * Copyright (C) 2020, Google LLC. + * Author: Daniel Latypov <dlatypov(a)google.com> + */ + +#include <kunit/test.h> +#include <linux/gcd.h> +#include <linux/kernel.h> +#include <linux/lcm.h> +#include <linux/reciprocal_div.h> + +static void abs_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, abs((char)0), (char)0); + KUNIT_EXPECT_EQ(test, abs((char)42), (char)42); + KUNIT_EXPECT_EQ(test, abs((char)-42), (char)42); + + /* The expression in the macro is actually promoted to an int. */ + KUNIT_EXPECT_EQ(test, abs((short)0), 0); + KUNIT_EXPECT_EQ(test, abs((short)42), 42); + KUNIT_EXPECT_EQ(test, abs((short)-42), 42); + + KUNIT_EXPECT_EQ(test, abs(0), 0); + KUNIT_EXPECT_EQ(test, abs(42), 42); + KUNIT_EXPECT_EQ(test, abs(-42), 42); + + KUNIT_EXPECT_EQ(test, abs(0L), 0L); + KUNIT_EXPECT_EQ(test, abs(42L), 42L); + KUNIT_EXPECT_EQ(test, abs(-42L), 42L); + + KUNIT_EXPECT_EQ(test, abs(0LL), 0LL); + KUNIT_EXPECT_EQ(test, abs(42LL), 42LL); + KUNIT_EXPECT_EQ(test, abs(-42LL), 42LL); + + /* Unsigned types get casted to signed. */ + KUNIT_EXPECT_EQ(test, abs(0ULL), 0LL); + KUNIT_EXPECT_EQ(test, abs(42ULL), 42LL); +} + +static void int_sqrt_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, int_sqrt(0UL), 0UL); + KUNIT_EXPECT_EQ(test, int_sqrt(1UL), 1UL); + KUNIT_EXPECT_EQ(test, int_sqrt(4UL), 2UL); + KUNIT_EXPECT_EQ(test, int_sqrt(5UL), 2UL); + KUNIT_EXPECT_EQ(test, int_sqrt(8UL), 2UL); + KUNIT_EXPECT_EQ(test, int_sqrt(1UL << 30), 1UL << 15); +} + +static void round_up_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, round_up(0, 1), 0); + KUNIT_EXPECT_EQ(test, round_up(1, 2), 2); + KUNIT_EXPECT_EQ(test, round_up(3, 2), 4); + KUNIT_EXPECT_EQ(test, round_up((1 << 30) - 1, 2), 1 << 30); + KUNIT_EXPECT_EQ(test, round_up((1 << 30) - 1, 1 << 29), 1 << 30); +} + +static void round_down_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, round_down(0, 1), 0); + KUNIT_EXPECT_EQ(test, round_down(1, 2), 0); + KUNIT_EXPECT_EQ(test, round_down(3, 2), 2); + KUNIT_EXPECT_EQ(test, round_down((1 << 30) - 1, 2), (1 << 30) - 2); + KUNIT_EXPECT_EQ(test, round_down((1 << 30) - 1, 1 << 29), 1 << 29); +} + +/* These versions can round to numbers that aren't a power of two */ +static void roundup_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, roundup(0, 1), 0); + KUNIT_EXPECT_EQ(test, roundup(1, 2), 2); + KUNIT_EXPECT_EQ(test, roundup(3, 2), 4); + KUNIT_EXPECT_EQ(test, roundup((1 << 30) - 1, 2), 1 << 30); + KUNIT_EXPECT_EQ(test, roundup((1 << 30) - 1, 1 << 29), 1 << 30); + + KUNIT_EXPECT_EQ(test, roundup(3, 2), 4); + KUNIT_EXPECT_EQ(test, roundup(4, 3), 6); +} + +static void rounddown_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, rounddown(0, 1), 0); + KUNIT_EXPECT_EQ(test, rounddown(1, 2), 0); + KUNIT_EXPECT_EQ(test, rounddown(3, 2), 2); + KUNIT_EXPECT_EQ(test, rounddown((1 << 30) - 1, 2), (1 << 30) - 2); + KUNIT_EXPECT_EQ(test, rounddown((1 << 30) - 1, 1 << 29), 1 << 29); + + KUNIT_EXPECT_EQ(test, rounddown(3, 2), 2); + KUNIT_EXPECT_EQ(test, rounddown(4, 3), 3); +} + +static void div_round_up_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(0, 1), 0); + KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(20, 10), 2); + KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(21, 10), 3); + KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(21, 20), 2); + KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(21, 99), 1); +} + +static void div_round_closest_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(0, 1), 0); + KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(20, 10), 2); + KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(21, 10), 2); + KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(25, 10), 3); +} + +/* Generic test case for unsigned long inputs. */ +struct test_case { + unsigned long a, b; + unsigned long result; +}; + +static struct test_case gcd_cases[] = { + { + .a = 0, .b = 0, + .result = 0, + }, + { + .a = 0, .b = 1, + .result = 1, + }, + { + .a = 2, .b = 2, + .result = 2, + }, + { + .a = 2, .b = 4, + .result = 2, + }, + { + .a = 3, .b = 5, + .result = 1, + }, + { + .a = 3 * 9, .b = 3 * 5, + .result = 3, + }, + { + .a = 3 * 5 * 7, .b = 3 * 5 * 11, + .result = 15, + }, + { + .a = 1 << 21, + .b = (1 << 21) - 1, + .result = 1, + }, +}; + +KUNIT_ARRAY_PARAM(gcd, gcd_cases, NULL); + +static void gcd_test(struct kunit *test) +{ + const char *message_fmt = "gcd(%lu, %lu)"; + const struct test_case *test_param = test->param_value; + + KUNIT_EXPECT_EQ_MSG(test, test_param->result, + gcd(test_param->a, test_param->b), + message_fmt, test_param->a, + test_param->b); + + if (test_param->a == test_param->b) + return; + + /* gcd(a,b) == gcd(b,a) */ + KUNIT_EXPECT_EQ_MSG(test, test_param->result, + gcd(test_param->b, test_param->a), + message_fmt, test_param->b, + test_param->a); +} + +static struct test_case lcm_cases[] = { + { + .a = 0, .b = 0, + .result = 0, + }, + { + .a = 0, .b = 1, + .result = 0, + }, + { + .a = 1, .b = 2, + .result = 2, + }, + { + .a = 2, .b = 2, + .result = 2, + }, + { + .a = 3 * 5, .b = 3 * 7, + .result = 3 * 5 * 7, + }, +}; + +KUNIT_ARRAY_PARAM(lcm, lcm_cases, NULL); + +static void lcm_test(struct kunit *test) +{ + const char *message_fmt = "lcm(%lu, %lu)"; + const struct test_case *test_param = test->param_value; + + KUNIT_EXPECT_EQ_MSG(test, test_param->result, + lcm(test_param->a, test_param->b), + message_fmt, test_param->a, + test_param->b); + + if (test_param->a == test_param->b) + return; + + /* lcm(a,b) == lcm(b,a) */ + KUNIT_EXPECT_EQ_MSG(test, test_param->result, + lcm(test_param->b, test_param->a), + message_fmt, test_param->b, + test_param->a); +} + +struct u32_test_case { + u32 a, b; + u32 result; +}; + +static struct u32_test_case reciprocal_div_cases[] = { + { + .a = 0, .b = 1, + .result = 0, + }, + { + .a = 42, .b = 20, + .result = 2, + }, + { + .a = 42, .b = 9999, + .result = 0, + }, + { + .a = (1 << 16), .b = (1 << 14), + .result = 1 << 2, + }, +}; + +KUNIT_ARRAY_PARAM(reciprocal_div, reciprocal_div_cases, NULL); + +static void reciprocal_div_test(struct kunit *test) +{ + const struct u32_test_case *test_param = test->param_value; + struct reciprocal_value rv = reciprocal_value(test_param->b); + + KUNIT_EXPECT_EQ_MSG(test, test_param->result, + reciprocal_divide(test_param->a, rv), + "reciprocal_divide(%u, %u)", + test_param->a, test_param->b); +} + +static void reciprocal_scale_test(struct kunit *test) +{ + KUNIT_EXPECT_EQ(test, reciprocal_scale(0u, 100), 0u); + KUNIT_EXPECT_EQ(test, reciprocal_scale(1u, 100), 0u); + KUNIT_EXPECT_EQ(test, reciprocal_scale(1u << 4, 1 << 28), 1u); + KUNIT_EXPECT_EQ(test, reciprocal_scale(1u << 16, 1 << 28), 1u << 12); + KUNIT_EXPECT_EQ(test, reciprocal_scale(~0u, 1 << 28), (1u << 28) - 1); +} + +static struct kunit_case math_test_cases[] = { + KUNIT_CASE(abs_test), + KUNIT_CASE(int_sqrt_test), + KUNIT_CASE(round_up_test), + KUNIT_CASE(round_down_test), + KUNIT_CASE(roundup_test), + KUNIT_CASE(rounddown_test), + KUNIT_CASE(div_round_up_test), + KUNIT_CASE(div_round_closest_test), + KUNIT_CASE_PARAM(gcd_test, gcd_gen_params), + KUNIT_CASE_PARAM(lcm_test, lcm_gen_params), + KUNIT_CASE_PARAM(reciprocal_div_test, reciprocal_div_gen_params), + KUNIT_CASE(reciprocal_scale_test), + {} +}; + +static struct kunit_suite math_test_suite = { + .name = "lib-math", + .test_cases = math_test_cases, +}; + +kunit_test_suites(&math_test_suite); + +MODULE_LICENSE("GPL v2"); base-commit: 7e25f40eab52c57ff6772d27d2aef3640a3237d7 -- 2.31.1.368.gbe11c130af-goog

11 months, 1 week

5
5
0 0

[PATCH v6 1/2] posix-timers: Prefer delivery of signals to the current thread

by Marco Elver

From: Dmitry Vyukov <dvyukov(a)google.com> POSIX timers using the CLOCK_PROCESS_CPUTIME_ID clock prefer the main thread of a thread group for signal delivery. However, this has a significant downside: it requires waking up a potentially idle thread. Instead, prefer to deliver signals to the current thread (in the same thread group) if SIGEV_THREAD_ID is not set by the user. This does not change guaranteed semantics, since POSIX process CPU time timers have never guaranteed that signal delivery is to a specific thread (without SIGEV_THREAD_ID set). The effect is that we no longer wake up potentially idle threads, and the kernel is no longer biased towards delivering the timer signal to any particular thread (which better distributes the timer signals esp. when multiple timers fire concurrently). Signed-off-by: Dmitry Vyukov <dvyukov(a)google.com> Suggested-by: Oleg Nesterov <oleg(a)redhat.com> Reviewed-by: Oleg Nesterov <oleg(a)redhat.com> Signed-off-by: Marco Elver <elver(a)google.com> --- v6: - Split test from this patch. - Update wording on what this patch aims to improve. v5: - Rebased onto v6.2. v4: - Restructured checks in send_sigqueue() as suggested. v3: - Switched to the completely different implementation (much simpler) based on the Oleg's idea. RFC v2: - Added additional Cc as Thomas asked. --- kernel/signal.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 8cb28f1df294..605445fa27d4 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1003,8 +1003,7 @@ static void complete_signal(int sig, struct task_struct *p, enum pid_type type) /* * Now find a thread we can wake up to take the signal off the queue. * - * If the main thread wants the signal, it gets first crack. - * Probably the least surprising to the average bear. + * Try the suggested task first (may or may not be the main thread). */ if (wants_signal(sig, p)) t = p; @@ -1970,8 +1969,23 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) ret = -1; rcu_read_lock(); + /* + * This function is used by POSIX timers to deliver a timer signal. + * Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID + * set), the signal must be delivered to the specific thread (queues + * into t->pending). + * + * Where type is not PIDTYPE_PID, signals must just be delivered to the + * current process. In this case, prefer to deliver to current if it is + * in the same thread group as the target, as it avoids unnecessarily + * waking up a potentially idle task. + */ t = pid_task(pid, type); - if (!t || !likely(lock_task_sighand(t, &flags))) + if (!t) + goto ret; + if (type != PIDTYPE_PID && same_thread_group(t, current)) + t = current; + if (!likely(lock_task_sighand(t, &flags))) goto ret; ret = 1; /* the signal is ignored */ @@ -1993,6 +2007,11 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) q->info.si_overrun = 0; signalfd_notify(t, sig); + /* + * If the type is not PIDTYPE_PID, we just use shared_pending, which + * won't guarantee that the specified task will receive the signal, but + * is sufficient if t==current in the common case. + */ pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending; list_add_tail(&q->list, &pending->list); sigaddset(&pending->signal, sig); -- 2.40.0.rc1.284.g88254d51c5-goog

1 year

9
50
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[PATCH v3] selftests/ftrace: traceonoff_triggers: strip off names

by Yipeng Zou

The func_traceonoff_triggers.tc sometimes goes to fail on my board, Kunpeng-920. [root@localhost]# ./ftracetest ./test.d/ftrace/func_traceonoff_triggers.tc -l fail.log === Ftrace unit tests === [1] ftrace - test for function traceon/off triggers [FAIL] [2] (instance) ftrace - test for function traceon/off triggers [UNSUPPORTED] I look up the log, and it shows that the md5sum is different between csum1 and csum2. ++ cnt=611 ++ sleep .1 +++ cnt_trace +++ grep -v '^#' trace +++ wc -l ++ cnt2=611 ++ '[' 611 -ne 611 ']' +++ cat tracing_on ++ on=0 ++ '[' 0 '!=' 0 ']' +++ md5sum trace ++ csum1='76896aa74362fff66a6a5f3cf8a8a500 trace' ++ sleep .1 +++ md5sum trace ++ csum2='ee8625a21c058818fc26e45c1ed3f6de trace' ++ '[' '76896aa74362fff66a6a5f3cf8a8a500 trace' '!=' 'ee8625a21c058818fc26e45c1ed3f6de trace' ']' ++ fail 'Tracing file is still changing' ++ echo Tracing file is still changing Tracing file is still changing ++ exit_fail ++ exit 1 So I directly dump the trace file before md5sum, the diff shows that: [root@localhost]# diff trace_1.log trace_2.log -y --suppress-common-lines dockerd-12285 [036] d.... 18385.510290: sched_stat | <...>-12285 [036] d.... 18385.510290: sched_stat dockerd-12285 [036] d.... 18385.510291: sched_swit | <...>-12285 [036] d.... 18385.510291: sched_swit <...>-740 [044] d.... 18385.602859: sched_stat | kworker/44:1-740 [044] d.... 18385.602859: sched_stat <...>-740 [044] d.... 18385.602860: sched_swit | kworker/44:1-740 [044] d.... 18385.602860: sched_swit And we can see that <...> filed be filled with names. We can strip off the names there to fix that. After strip off the names: kworker/u257:0-12 [019] d..2. 2528.758910: sched_stat | -12 [019] d..2. 2528.758910: sched_stat_runtime: comm=k kworker/u257:0-12 [019] d..2. 2528.758912: sched_swit | -12 [019] d..2. 2528.758912: sched_switch: prev_comm=kw <idle>-0 [000] d.s5. 2528.762318: sched_waki | -0 [000] d.s5. 2528.762318: sched_waking: comm=sshd pi <idle>-0 [037] dNh2. 2528.762326: sched_wake | -0 [037] dNh2. 2528.762326: sched_wakeup: comm=sshd pi <idle>-0 [037] d..2. 2528.762334: sched_swit | -0 [037] d..2. 2528.762334: sched_switch: prev_comm=sw Fixes: d87b29179aa0 ("selftests: ftrace: Use md5sum to take less time of checking logs") Suggested-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> Signed-off-by: Yipeng Zou <zouyipeng(a)huawei.com> Acked-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- .../ftrace/test.d/ftrace/func_traceonoff_triggers.tc | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc index aee22289536b..1b57771dbfdf 100644 --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc @@ -90,9 +90,10 @@ if [ $on != "0" ]; then fail "Tracing is not off" fi -csum1=`md5sum trace` +# Cannot rely on names being around as they are only cached, strip them +csum1=`cat trace | sed -e 's/^ *[^ ]*$-[0-9][0-9]*$/\1/' | md5sum` sleep $SLEEP_TIME -csum2=`md5sum trace` +csum2=`cat trace | sed -e 's/^ *[^ ]*$-[0-9][0-9]*$/\1/' | md5sum` if [ "$csum1" != "$csum2" ]; then fail "Tracing file is still changing" -- 2.34.1

1 year

2
2
0 0

[PATCH v2] selftests: sud_test: return correct emulated syscall value on RISC-V

by Clément Léger

Currently, the sud_test expects the emulated syscall to return the emulated syscall number. This assumption only works on architectures were the syscall calling convention use the same register for syscall number/syscall return value. This is not the case for RISC-V and thus the return value must be also emulated using the provided ucontext. Signed-off-by: Clément Léger <cleger(a)rivosinc.com> Reviewed-by: Palmer Dabbelt <palmer(a)rivosinc.com> Acked-by: Palmer Dabbelt <palmer(a)rivosinc.com> --- Changes in V2: - Changes comment to be more explicit - Use A7 syscall arg rather than hardcoding MAGIC_SYSCALL_1 --- .../selftests/syscall_user_dispatch/sud_test.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/syscall_user_dispatch/sud_test.c b/tools/testing/selftests/syscall_user_dispatch/sud_test.c index b5d592d4099e..d975a6767329 100644 --- a/tools/testing/selftests/syscall_user_dispatch/sud_test.c +++ b/tools/testing/selftests/syscall_user_dispatch/sud_test.c @@ -158,6 +158,20 @@ static void handle_sigsys(int sig, siginfo_t *info, void *ucontext) /* In preparation for sigreturn. */ SYSCALL_DISPATCH_OFF(glob_sel); + + /* + * The tests for argument handling assume that `syscall(x) == x`. This + * is a NOP on x86 because the syscall number is passed in %rax, which + * happens to also be the function ABI return register. Other + * architectures may need to swizzle the arguments around. + */ +#if defined(__riscv) +/* REG_A7 is not defined in libc headers */ +# define REG_A7 (REG_A0 + 7) + + ((ucontext_t *)ucontext)->uc_mcontext.__gregs[REG_A0] = + ((ucontext_t *)ucontext)->uc_mcontext.__gregs[REG_A7]; +#endif } TEST(dispatch_and_return) -- 2.43.0

1 year

3
2
0 0

[PATCH] KVM: selftests: Use TAP in the steal_time test

by Thomas Huth

For easier use of the tests in automation and for having some status information for the user while the test is running, let's provide some TAP output in this test. Signed-off-by: Thomas Huth <thuth(a)redhat.com> --- NB: This patch does not use the interface from kselftest_harness.h since it is not very suitable for the for-loop in this patch. tools/testing/selftests/kvm/steal_time.c | 46 ++++++++++++------------ 1 file changed, 23 insertions(+), 23 deletions(-) diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c index 171adfb2a6cb..aa6149eb9ea1 100644 --- a/tools/testing/selftests/kvm/steal_time.c +++ b/tools/testing/selftests/kvm/steal_time.c @@ -81,20 +81,18 @@ static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i) static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx) { struct kvm_steal_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpu_idx]); - int i; - pr_info("VCPU%d:\n", vcpu_idx); - pr_info(" steal: %lld\n", st->steal); - pr_info(" version: %d\n", st->version); - pr_info(" flags: %d\n", st->flags); - pr_info(" preempted: %d\n", st->preempted); - pr_info(" u8_pad: "); - for (i = 0; i < 3; ++i) - pr_info("%d", st->u8_pad[i]); - pr_info("\n pad: "); - for (i = 0; i < 11; ++i) - pr_info("%d", st->pad[i]); - pr_info("\n"); + ksft_print_msg("VCPU%d:\n", vcpu_idx); + ksft_print_msg(" steal: %lld\n", st->steal); + ksft_print_msg(" version: %d\n", st->version); + ksft_print_msg(" flags: %d\n", st->flags); + ksft_print_msg(" preempted: %d\n", st->preempted); + ksft_print_msg(" u8_pad: %d %d %d\n", + st->u8_pad[0], st->u8_pad[1], st->u8_pad[2]); + ksft_print_msg(" pad: %d %d %d %d %d %d %d %d %d %d %d\n", + st->pad[0], st->pad[1], st->pad[2], st->pad[3], + st->pad[4], st->pad[5], st->pad[6], st->pad[7], + st->pad[8], st->pad[9], st->pad[10]); } #elif defined(__aarch64__) @@ -197,10 +195,10 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx) { struct st_time *st = addr_gva2hva(vm, (ulong)st_gva[vcpu_idx]); - pr_info("VCPU%d:\n", vcpu_idx); - pr_info(" rev: %d\n", st->rev); - pr_info(" attr: %d\n", st->attr); - pr_info(" st_time: %ld\n", st->st_time); + ksft_print_msg("VCPU%d:\n", vcpu_idx); + ksft_print_msg(" rev: %d\n", st->rev); + ksft_print_msg(" attr: %d\n", st->attr); + ksft_print_msg(" st_time: %ld\n", st->st_time); } #endif @@ -267,7 +265,9 @@ int main(int ac, char **av) vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, ST_GPA_BASE, 1, gpages, 0); virt_map(vm, ST_GPA_BASE, ST_GPA_BASE, gpages); + ksft_print_header(); TEST_REQUIRE(is_steal_time_supported(vcpus[0])); + ksft_set_plan(NR_VCPUS); /* Run test on each VCPU */ for (i = 0; i < NR_VCPUS; ++i) { @@ -308,14 +308,14 @@ int main(int ac, char **av) run_delay, stolen_time); if (verbose) { - pr_info("VCPU%d: total-stolen-time=%ld test-stolen-time=%ld", i, - guest_stolen_time[i], stolen_time); - if (stolen_time == run_delay) - pr_info(" (BONUS: guest test-stolen-time even exactly matches test-run_delay)"); - pr_info("\n"); + ksft_print_msg("VCPU%d: total-stolen-time=%ld test-stolen-time=%ld%s\n", + i, guest_stolen_time[i], stolen_time, + stolen_time == run_delay ? + " (BONUS: guest test-stolen-time even exactly matches test-run_delay)" : ""); steal_time_dump(vm, i); } + ksft_test_result_pass("vcpu%d\n", i); } - return 0; + ksft_finished(); /* Print results and exit() accordingly */ } -- 2.41.0

1 year

5
6
0 0

[PATCH 0/8] iommufd support pasid attach/replace

by Yi Liu

PASID (Process Address Space ID) is a PCIe extension to tag the DMA transactions out of a physical device, and most modern IOMMU hardware have supported PASID granular address translation. So a PASID-capable device can be attached to multiple hwpts (a.k.a. domains), each attachment is tagged with a pasid. This series first adds a missing iommu API to replace domain for a pasid, then adds iommufd APIs for device drivers to attach/replace/detach pasid to/from hwpt per userspace's request, and adds selftest to validate the iommufd APIs. pasid attach/replace is mandatory on Intel VT-d given the PASID table locates in the physical address space hence must be managed by the kernel, both for supporting vSVA and coming SIOV. But it's optional on ARM/AMD which allow configuring the PASID/CD table either in host physical address space or nested on top of an GPA address space. This series only add VT-d support as the minimal requirement. Complete code can be found in below link: https://github.com/yiliu1765/iommufd/tree/iommufd_pasid Change log: v1: - Implemnet iommu_replace_device_pasid() to fall back to the original domain if this replacement failed (Kevin) - Add check in do_attach() to check corressponding attach_fn per the pasid value. rfc: https://lore.kernel.org/linux-iommu/20230926092651.17041-1-yi.l.liu@intel.c… Regards, Yi Liu Kevin Tian (1): iommufd: Support attach/replace hwpt per pasid Lu Baolu (2): iommu: Introduce a replace API for device pasid iommu/vt-d: Add set_dev_pasid callback for nested domain Yi Liu (5): iommufd: replace attach_fn with a structure iommufd/selftest: Add set_dev_pasid and remove_dev_pasid in mock iommu iommufd/selftest: Add a helper to get test device iommufd/selftest: Add test ops to test pasid attach/detach iommufd/selftest: Add coverage for iommufd pasid attach/detach drivers/iommu/intel/nested.c | 47 +++++ drivers/iommu/iommu-priv.h | 2 + drivers/iommu/iommu.c | 82 ++++++-- drivers/iommu/iommufd/Makefile | 1 + drivers/iommu/iommufd/device.c | 50 +++-- drivers/iommu/iommufd/iommufd_private.h | 23 +++ drivers/iommu/iommufd/iommufd_test.h | 24 +++ drivers/iommu/iommufd/pasid.c | 138 ++++++++++++++ drivers/iommu/iommufd/selftest.c | 176 ++++++++++++++++-- include/linux/iommufd.h | 6 + tools/testing/selftests/iommu/iommufd.c | 172 +++++++++++++++++ .../selftests/iommu/iommufd_fail_nth.c | 28 ++- tools/testing/selftests/iommu/iommufd_utils.h | 78 ++++++++ 13 files changed, 785 insertions(+), 42 deletions(-) create mode 100644 drivers/iommu/iommufd/pasid.c -- 2.34.1

1 year, 1 month

5
35
0 0

[PATCH v3 0/2] selftests/vDSO: Fix errors on LoongArch

by Tiezhu Yang

v3: Rebase on the next branch of linux-kselftest.git, modify the patch title and update the commit message v2: Rebase on 6.5-rc1 and update the commit message Tiezhu Yang (2): selftests/vDSO: Fix building errors on LoongArch selftests/vDSO: Fix runtime errors on LoongArch tools/testing/selftests/vDSO/vdso_config.h | 6 ++++- .../testing/selftests/vDSO/vdso_test_getcpu.c | 16 +++++------- .../selftests/vDSO/vdso_test_gettimeofday.c | 26 +++++-------------- 3 files changed, 18 insertions(+), 30 deletions(-) -- 2.42.0

1 year, 1 month

2
10
0 0

[net-next v1 00/16] Device Memory TCP

by Mina Almasry

Major changes in v1: -------------- 1. Implemented MVP queue API ndos to remove the userspace-visible driver reset. 2. Fixed issues in the napi_pp_put_page() devmem frag unref path. 3. Removed RFC tag. Many smaller addressed comments across all the patches (patches have individual change log). Full tree including the rest of the GVE driver changes: https://github.com/mina/linux/commits/tcpdevmem-v1 Cc: Yunsheng Lin <linyunsheng(a)huawei.com> Cc: Shailend Chand <shailend(a)google.com> Cc: Harshitha Ramamurthy <hramamurthy(a)google.com> Changes in RFC v3: ------------------ 1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the series reviewable and mergable. 2. Implemented multi-rx-queue binding which was a todo in v2. 3. Fix to cmsg handling. The sticking point in RFC v2[2] was the device reset required to refill the device rx-queues after the dmabuf bind/unbind. The solution suggested as I understand is a subset of the per-queue management ops Jakub suggested or similar: https://lore.kernel.org/netdev/20230815171638.4c057dcd@kernel.org/ This is not addressed in this revision, because: 1. This point was discussed at netconf & netdev and there is openness to using the current approach of requiring a device reset. 2. Implementing individual queue resetting seems to be difficult for my test bed with GVE. My prototype to test this ran into issues with the rx-queues not coming back up properly if reset individually. At the moment I'm unsure if it's a mistake in the POC or a genuine issue in the virtualization stack behind GVE, which currently doesn't test individual rx-queue restart. 3. Our usecases are not bothered by requiring a device reset to refill the buffer queues, and we'd like to support NICs that run into this limitation with resetting individual queues. My thought is that drivers that have trouble with per-queue configs can use the support in this series, while drivers that support new netdev ops to reset individual queues can automatically reset the queue as part of the dma-buf bind/unbind. The same approach with device resets is presented again for consideration with other sticking points addressed. This proposal includes the rx devmem path only proposed for merge. For a snapshot of my entire tree which includes the GVE POC page pool support & device memory support: https://github.com/torvalds/linux/compare/master...mina:linux:tcpdevmem-v3 [1] https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.… [2] https://lore.kernel.org/netdev/CAHS8izOVJGJH5WF68OsRWFKJid1_huzzUK+hpKbLcL4… Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Jeroen de Borst <jeroendb(a)google.com> Cc: Praveen Kaligineedi <pkaligineedi(a)google.com> Changes in RFC v2: ------------------ The sticking point in RFC v1[1] was the dma-buf pages approach we used to deliver the device memory to the TCP stack. RFC v2 is a proof-of-concept that attempts to resolve this by implementing scatterlist support in the networking stack, such that we can import the dma-buf scatterlist directly. This is the approach proposed at a high level here[2]. Detailed changes: 1. Replaced dma-buf pages approach with importing scatterlist into the page pool. 2. Replace the dma-buf pages centric API with a netlink API. 3. Removed the TX path implementation - there is no issue with implementing the TX path with scatterlist approach, but leaving out the TX path makes it easier to review. 4. Functionality is tested with this proposal, but I have not conducted perf testing yet. I'm not sure there are regressions, but I removed perf claims from the cover letter until they can be re-confirmed. 5. Added Signed-off-by: contributors to the implementation. 6. Fixed some bugs with the RX path since RFC v1. Any feedback welcome, but specifically the biggest pending questions needing feedback IMO are: 1. Feedback on the scatterlist-based approach in general. 2. Netlink API (Patch 1 & 2). 3. Approach to handle all the drivers that expect to receive pages from the page pool (Patch 6). [1] https://lore.kernel.org/netdev/dfe4bae7-13a0-3c5d-d671-f61b375cb0b4@gmail.c… [2] https://lore.kernel.org/netdev/CAHS8izPm6XRS54LdCDZVd0C75tA1zHSu6jLVO8nzTLX… ---------------------- * TL;DR: Device memory TCP (devmem TCP) is a proposal for transferring data to and/or from device memory efficiently, without bouncing the data to a host memory buffer. * Problem: A large amount of data transfers have device memory as the source and/or destination. Accelerators drastically increased the volume of such transfers. Some examples include: - ML accelerators transferring large amounts of training data from storage into GPU/TPU memory. In some cases ML training setup time can be as long as 50% of TPU compute time, improving data transfer throughput & efficiency can help improving GPU/TPU utilization. - Distributed training, where ML accelerators, such as GPUs on different hosts, exchange data among them. - Distributed raw block storage applications transfer large amounts of data with remote SSDs, much of this data does not require host processing. Today, the majority of the Device-to-Device data transfers the network are implemented as the following low level operations: Device-to-Host copy, Host-to-Host network transfer, and Host-to-Device copy. The implementation is suboptimal, especially for bulk data transfers, and can put significant strains on system resources, such as host memory bandwidth, PCIe bandwidth, etc. One important reason behind the current state is the kernel’s lack of semantics to express device to network transfers. * Proposal: In this patch series we attempt to optimize this use case by implementing socket APIs that enable the user to: 1. send device memory across the network directly, and 2. receive incoming network packets directly into device memory. Packet _payloads_ go directly from the NIC to device memory for receive and from device memory to NIC for transmit. Packet _headers_ go to/from host memory and are processed by the TCP/IP stack normally. The NIC _must_ support header split to achieve this. Advantages: - Alleviate host memory bandwidth pressure, compared to existing network-transfer + device-copy semantics. - Alleviate PCIe BW pressure, by limiting data transfer to the lowest level of the PCIe tree, compared to traditional path which sends data through the root complex. * Patch overview: ** Part 1: netlink API Gives user ability to bind dma-buf to an RX queue. ** Part 2: scatterlist support Currently the standard for device memory sharing is DMABUF, which doesn't generate struct pages. On the other hand, networking stack (skbs, drivers, and page pool) operate on pages. We have 2 options: 1. Generate struct pages for dmabuf device memory, or, 2. Modify the networking stack to process scatterlist. Approach #1 was attempted in RFC v1. RFC v2 implements approach #2. ** part 3: page pool support We piggy back on page pool memory providers proposal: https://github.com/kuba-moo/linux/tree/pp-providers It allows the page pool to define a memory provider that provides the page allocation and freeing. It helps abstract most of the device memory TCP changes from the driver. ** part 4: support for unreadable skb frags Page pool iovs are not accessible by the host; we implement changes throughput the networking stack to correctly handle skbs with unreadable frags. ** Part 5: recvmsg() APIs We define user APIs for the user to send and receive device memory. Not included with this RFC is the GVE devmem TCP support, just to simplify the review. Code available here if desired: https://github.com/mina/linux/tree/tcpdevmem This RFC is built on top of net-next with Jakub's pp-providers changes cherry-picked. * NIC dependencies: 1. (strict) Devmem TCP require the NIC to support header split, i.e. the capability to split incoming packets into a header + payload and to put each into a separate buffer. Devmem TCP works by using device memory for the packet payload, and host memory for the packet headers. 2. (optional) Devmem TCP works better with flow steering support & RSS support, i.e. the NIC's ability to steer flows into certain rx queues. This allows the sysadmin to enable devmem TCP on a subset of the rx queues, and steer devmem TCP traffic onto these queues and non devmem TCP elsewhere. The NIC I have access to with these properties is the GVE with DQO support running in Google Cloud, but any NIC that supports these features would suffice. I may be able to help reviewers bring up devmem TCP on their NICs. * Testing: The series includes a udmabuf kselftest that show a simple use case of devmem TCP and validates the entire data path end to end without a dependency on a specific dmabuf provider. ** Test Setup Kernel: net-next with this RFC and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Jakub Kicinski (2): net: page_pool: factor out releasing DMA from releasing the page net: page_pool: create hooks for custom page providers Mina Almasry (14): queue_api: define queue api gve: implement queue api net: netdev netlink api to bind dma-buf to a net device netdev: support binding dma-buf to netdevice netdev: netdevice devmem allocator memory-provider: dmabuf devmem memory provider page_pool: device memory support page_pool: don't release iov on elevanted refcount net: support non paged skb frags net: add support for skbs with unreadable frags tcp: RX path for devmem TCP net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags net: add devmem TCP documentation selftests: add ncdevmem, netcat for devmem TCP Documentation/netlink/specs/netdev.yaml | 52 ++ Documentation/networking/devmem.rst | 270 ++++++++++ drivers/net/ethernet/google/gve/gve_adminq.c | 6 +- drivers/net/ethernet/google/gve/gve_adminq.h | 3 + drivers/net/ethernet/google/gve/gve_dqo.h | 2 + drivers/net/ethernet/google/gve/gve_main.c | 286 +++++++++++ drivers/net/ethernet/google/gve/gve_rx_dqo.c | 5 +- include/linux/netdevice.h | 24 + include/linux/skbuff.h | 56 ++- include/linux/socket.h | 1 + include/net/devmem.h | 109 +++++ include/net/netdev_rx_queue.h | 1 + include/net/page_pool/helpers.h | 162 +++++- include/net/page_pool/types.h | 48 ++ include/net/sock.h | 2 + include/net/tcp.h | 5 +- include/uapi/asm-generic/socket.h | 6 + include/uapi/linux/netdev.h | 19 + include/uapi/linux/uio.h | 14 + net/core/datagram.c | 6 + net/core/dev.c | 314 +++++++++++- net/core/gro.c | 7 +- net/core/netdev-genl-gen.c | 19 + net/core/netdev-genl-gen.h | 2 + net/core/netdev-genl.c | 124 +++++ net/core/page_pool.c | 239 +++++++-- net/core/skbuff.c | 108 +++- net/core/sock.c | 38 ++ net/ipv4/tcp.c | 196 +++++++- net/ipv4/tcp_input.c | 13 +- net/ipv4/tcp_ipv4.c | 8 + net/ipv4/tcp_output.c | 5 +- net/packet/af_packet.c | 4 +- tools/include/uapi/linux/netdev.h | 19 + tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 5 + tools/testing/selftests/net/ncdevmem.c | 489 +++++++++++++++++++ 37 files changed, 2585 insertions(+), 83 deletions(-) create mode 100644 Documentation/networking/devmem.rst create mode 100644 include/net/devmem.h create mode 100644 tools/testing/selftests/net/ncdevmem.c -- 2.43.0.472.g3155946c3a-goog

1 year, 1 month

14
74
0 0

[PATCH] kselftest: Add basic test for probing the rust sample modules

by Laura Nao

Add new basic kselftest that checks if the available rust sample modules can be added and removed correctly. Signed-off-by: Laura Nao <laura.nao(a)collabora.com> --- MAINTAINERS | 1 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/rust/.gitignore | 1 + tools/testing/selftests/rust/Makefile | 8 ++++ .../selftests/rust/test_probe_samples.sh | 42 +++++++++++++++++++ 5 files changed, 53 insertions(+) create mode 100644 tools/testing/selftests/rust/.gitignore create mode 100644 tools/testing/selftests/rust/Makefile create mode 100755 tools/testing/selftests/rust/test_probe_samples.sh diff --git a/MAINTAINERS b/MAINTAINERS index e2c6187a3ac8..acf283a5d2c0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18847,6 +18847,7 @@ F: Documentation/rust/ F: rust/ F: samples/rust/ F: scripts/*rust* +F: tools/testing/selftests/rust/ K: \b(?i:rust)\b RXRPC SOCKETS (AF_RXRPC) diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 3b2061d1c1a5..26140426c849 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -74,6 +74,7 @@ TARGETS += riscv TARGETS += rlimits TARGETS += rseq TARGETS += rtc +TARGETS += rust TARGETS += seccomp TARGETS += sgx TARGETS += sigaltstack diff --git a/tools/testing/selftests/rust/.gitignore b/tools/testing/selftests/rust/.gitignore new file mode 100644 index 000000000000..e3c5c04d1b19 --- /dev/null +++ b/tools/testing/selftests/rust/.gitignore @@ -0,0 +1 @@ +ktap_helpers.sh diff --git a/tools/testing/selftests/rust/Makefile b/tools/testing/selftests/rust/Makefile new file mode 100644 index 000000000000..ccaa50f35b5b --- /dev/null +++ b/tools/testing/selftests/rust/Makefile @@ -0,0 +1,8 @@ + +TEST_PROGS += test_probe_samples.sh +TEST_GEN_FILES := ktap_helpers.sh + +include ../lib.mk + +$(OUTPUT)/ktap_helpers.sh: + cp $(top_srcdir)/tools/testing/selftests/dt/ktap_helpers.sh $@ diff --git a/tools/testing/selftests/rust/test_probe_samples.sh b/tools/testing/selftests/rust/test_probe_samples.sh new file mode 100755 index 000000000000..a46550543f73 --- /dev/null +++ b/tools/testing/selftests/rust/test_probe_samples.sh @@ -0,0 +1,42 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (c) 2023 Collabora Ltd +# +# This script tests whether the rust sample modules can +# be added and removed correctly. +# + +DIR="$(dirname "$(readlink -f "$0")")" + +source "${DIR}"/ktap_helpers.sh + +rust_sample_modules=("rust_minimal" "rust_print") + +KSFT_PASS=0 +KSFT_FAIL=1 +KSFT_SKIP=4 + +ret="${KSFT_PASS}" + +ktap_print_header + +ktap_set_plan "${#rust_sample_modules[@]}" + +for sample in "${rust_sample_modules[@]}"; do + if ! /sbin/modprobe -n -q "$sample"; then + ktap_test_skip "module $sample is not found in /lib/modules/$(uname -r)" + continue + fi + + if /sbin/modprobe -q "$sample"; then + /sbin/modprobe -q -r "$sample" + ktap_test_pass "$sample" + else + ret="${KSFT_FAIL}" + ktap_test_fail "$sample" + fi +done + +ktap_print_totals +exit "${ret}" -- 2.30.2

1 year, 2 months

4
5
0 0

[RFC PATCH net-next v5 00/14] Device Memory TCP

by Mina Almasry

Major changes in RFC v5: ------------------------ 1. Rebased on top of 'Abstract page from net stack' series and used the new netmem type to refer to LSB set pointers instead of re-using struct page. 2. Downgraded this series back to RFC and called it RFC v5. This is because this series is now dependent on 'Abstract page from net stack'[1] and the queue API. Both are removed from the series to pre-requisite work. 3. Reworked the page_pool devmem support to use netmem and for some more unified handling. 4. Reworked the reference counting of net_iov (renamed from page_pool_iov) to use pp_ref_count for refcounting. The full changes including the dependent series and GVE page pool support is here: https://github.com/mina/linux/commits/tcpdevmem-rfcv5/ [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=810774 Major changes in v1: -------------------- 1. Implemented MVP queue API ndos to remove the userspace-visible driver reset. 2. Fixed issues in the napi_pp_put_page() devmem frag unref path. 3. Removed RFC tag. Many smaller addressed comments across all the patches (patches have individual change log). Full tree including the rest of the GVE driver changes: https://github.com/mina/linux/commits/tcpdevmem-v1 Changes in RFC v3: ------------------ 1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the series reviewable and mergable. 2. Implemented multi-rx-queue binding which was a todo in v2. 3. Fix to cmsg handling. The sticking point in RFC v2[2] was the device reset required to refill the device rx-queues after the dmabuf bind/unbind. The solution suggested as I understand is a subset of the per-queue management ops Jakub suggested or similar: https://lore.kernel.org/netdev/20230815171638.4c057dcd@kernel.org/ This is not addressed in this revision, because: 1. This point was discussed at netconf & netdev and there is openness to using the current approach of requiring a device reset. 2. Implementing individual queue resetting seems to be difficult for my test bed with GVE. My prototype to test this ran into issues with the rx-queues not coming back up properly if reset individually. At the moment I'm unsure if it's a mistake in the POC or a genuine issue in the virtualization stack behind GVE, which currently doesn't test individual rx-queue restart. 3. Our usecases are not bothered by requiring a device reset to refill the buffer queues, and we'd like to support NICs that run into this limitation with resetting individual queues. My thought is that drivers that have trouble with per-queue configs can use the support in this series, while drivers that support new netdev ops to reset individual queues can automatically reset the queue as part of the dma-buf bind/unbind. The same approach with device resets is presented again for consideration with other sticking points addressed. This proposal includes the rx devmem path only proposed for merge. For a snapshot of my entire tree which includes the GVE POC page pool support & device memory support: https://github.com/torvalds/linux/compare/master...mina:linux:tcpdevmem-v3 [1] https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.… [2] https://lore.kernel.org/netdev/CAHS8izOVJGJH5WF68OsRWFKJid1_huzzUK+hpKbLcL4… Changes in RFC v2: ------------------ The sticking point in RFC v1[1] was the dma-buf pages approach we used to deliver the device memory to the TCP stack. RFC v2 is a proof-of-concept that attempts to resolve this by implementing scatterlist support in the networking stack, such that we can import the dma-buf scatterlist directly. This is the approach proposed at a high level here[2]. Detailed changes: 1. Replaced dma-buf pages approach with importing scatterlist into the page pool. 2. Replace the dma-buf pages centric API with a netlink API. 3. Removed the TX path implementation - there is no issue with implementing the TX path with scatterlist approach, but leaving out the TX path makes it easier to review. 4. Functionality is tested with this proposal, but I have not conducted perf testing yet. I'm not sure there are regressions, but I removed perf claims from the cover letter until they can be re-confirmed. 5. Added Signed-off-by: contributors to the implementation. 6. Fixed some bugs with the RX path since RFC v1. Any feedback welcome, but specifically the biggest pending questions needing feedback IMO are: 1. Feedback on the scatterlist-based approach in general. 2. Netlink API (Patch 1 & 2). 3. Approach to handle all the drivers that expect to receive pages from the page pool (Patch 6). [1] https://lore.kernel.org/netdev/dfe4bae7-13a0-3c5d-d671-f61b375cb0b4@gmail.c… [2] https://lore.kernel.org/netdev/CAHS8izPm6XRS54LdCDZVd0C75tA1zHSu6jLVO8nzTLX… ---------------------- * TL;DR: Device memory TCP (devmem TCP) is a proposal for transferring data to and/or from device memory efficiently, without bouncing the data to a host memory buffer. * Problem: A large amount of data transfers have device memory as the source and/or destination. Accelerators drastically increased the volume of such transfers. Some examples include: - ML accelerators transferring large amounts of training data from storage into GPU/TPU memory. In some cases ML training setup time can be as long as 50% of TPU compute time, improving data transfer throughput & efficiency can help improving GPU/TPU utilization. - Distributed training, where ML accelerators, such as GPUs on different hosts, exchange data among them. - Distributed raw block storage applications transfer large amounts of data with remote SSDs, much of this data does not require host processing. Today, the majority of the Device-to-Device data transfers the network are implemented as the following low level operations: Device-to-Host copy, Host-to-Host network transfer, and Host-to-Device copy. The implementation is suboptimal, especially for bulk data transfers, and can put significant strains on system resources, such as host memory bandwidth, PCIe bandwidth, etc. One important reason behind the current state is the kernel’s lack of semantics to express device to network transfers. * Proposal: In this patch series we attempt to optimize this use case by implementing socket APIs that enable the user to: 1. send device memory across the network directly, and 2. receive incoming network packets directly into device memory. Packet _payloads_ go directly from the NIC to device memory for receive and from device memory to NIC for transmit. Packet _headers_ go to/from host memory and are processed by the TCP/IP stack normally. The NIC _must_ support header split to achieve this. Advantages: - Alleviate host memory bandwidth pressure, compared to existing network-transfer + device-copy semantics. - Alleviate PCIe BW pressure, by limiting data transfer to the lowest level of the PCIe tree, compared to traditional path which sends data through the root complex. * Patch overview: ** Part 1: netlink API Gives user ability to bind dma-buf to an RX queue. ** Part 2: scatterlist support Currently the standard for device memory sharing is DMABUF, which doesn't generate struct pages. On the other hand, networking stack (skbs, drivers, and page pool) operate on pages. We have 2 options: 1. Generate struct pages for dmabuf device memory, or, 2. Modify the networking stack to process scatterlist. ** part 3: page pool support We piggy back on page pool memory providers proposal: https://github.com/kuba-moo/linux/tree/pp-providers It allows the page pool to define a memory provider that provides the page allocation and freeing. It helps abstract most of the device memory TCP changes from the driver. ** part 4: support for unreadable skb frags Page pool iovs are not accessible by the host; we implement changes throughput the networking stack to correctly handle skbs with unreadable frags. ** Part 5: recvmsg() APIs We define user APIs for the user to send and receive device memory. Not included with this series is the GVE devmem TCP support, just to simplify the review. Code available here if desired: https://github.com/mina/linux/tree/tcpdevmem This series is built on top of net-next with Jakub's pp-providers changes cherry-picked. * NIC dependencies: 1. (strict) Devmem TCP require the NIC to support header split, i.e. the capability to split incoming packets into a header + payload and to put each into a separate buffer. Devmem TCP works by using device memory for the packet payload, and host memory for the packet headers. 2. (optional) Devmem TCP works better with flow steering support & RSS support, i.e. the NIC's ability to steer flows into certain rx queues. This allows the sysadmin to enable devmem TCP on a subset of the rx queues, and steer devmem TCP traffic onto these queues and non devmem TCP elsewhere. The NIC I have access to with these properties is the GVE with DQO support running in Google Cloud, but any NIC that supports these features would suffice. I may be able to help reviewers bring up devmem TCP on their NICs. * Testing: The series includes a udmabuf kselftest that show a simple use case of devmem TCP and validates the entire data path end to end without a dependency on a specific dmabuf provider. ** Test Setup Kernel: net-next with this series and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Cc: Pavel Begunkov <asml.silence(a)gmail.com> Cc: David Wei <dw(a)davidwei.uk> Cc: Jason Gunthorpe <jgg(a)ziepe.ca> Cc: Yunsheng Lin <linyunsheng(a)huawei.com> Cc: Shailend Chand <shailend(a)google.com> Cc: Harshitha Ramamurthy <hramamurthy(a)google.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Jeroen de Borst <jeroendb(a)google.com> Cc: Praveen Kaligineedi <pkaligineedi(a)google.com> Jakub Kicinski (1): net: page_pool: create hooks for custom page providers Mina Almasry (13): net: page_pool: factor out page_pool recycle check net: netdev netlink api to bind dma-buf to a net device netdev: support binding dma-buf to netdevice netdev: netdevice devmem allocator page_pool: convert to use netmem page_pool: devmem support memory-provider: dmabuf devmem memory provider net: support non paged skb frags net: add support for skbs with unreadable frags tcp: RX path for devmem TCP net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags net: add devmem TCP documentation selftests: add ncdevmem, netcat for devmem TCP Documentation/netlink/specs/netdev.yaml | 52 +++ Documentation/networking/devmem.rst | 271 +++++++++++++ Documentation/networking/index.rst | 1 + arch/alpha/include/uapi/asm/socket.h | 8 +- arch/mips/include/uapi/asm/socket.h | 6 + arch/parisc/include/uapi/asm/socket.h | 6 + arch/sparc/include/uapi/asm/socket.h | 6 + include/linux/skbuff.h | 68 +++- include/linux/socket.h | 1 + include/net/devmem.h | 127 ++++++ include/net/netdev_rx_queue.h | 1 + include/net/netmem.h | 223 ++++++++++- include/net/page_pool/helpers.h | 117 ++++-- include/net/page_pool/types.h | 27 +- include/net/sock.h | 2 + include/net/tcp.h | 5 +- include/trace/events/page_pool.h | 28 +- include/uapi/asm-generic/socket.h | 6 + include/uapi/linux/netdev.h | 19 + include/uapi/linux/uio.h | 14 + net/bpf/test_run.c | 5 +- net/core/datagram.c | 6 + net/core/dev.c | 314 ++++++++++++++- net/core/gro.c | 7 +- net/core/netdev-genl-gen.c | 19 + net/core/netdev-genl-gen.h | 2 + net/core/netdev-genl.c | 123 ++++++ net/core/page_pool.c | 419 +++++++++++++------- net/core/skbuff.c | 92 ++++- net/core/sock.c | 45 +++ net/ipv4/tcp.c | 196 +++++++++- net/ipv4/tcp_input.c | 13 +- net/ipv4/tcp_ipv4.c | 9 + net/ipv4/tcp_output.c | 5 +- net/packet/af_packet.c | 4 +- tools/include/uapi/linux/netdev.h | 19 + tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 5 + tools/testing/selftests/net/ncdevmem.c | 489 ++++++++++++++++++++++++ 39 files changed, 2527 insertions(+), 234 deletions(-) create mode 100644 Documentation/networking/devmem.rst create mode 100644 include/net/devmem.h create mode 100644 tools/testing/selftests/net/ncdevmem.c -- 2.43.0.472.g3155946c3a-goog

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Linux-kselftest-mirror December 2023