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Merge tag 'rcu.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Browse Source 
Pull RCU updates from Paul McKenney:

 - Documentation updates, perhaps most notably Neil Brown's writeup of
   the reference-counting analogy to RCU.

 - Expedited grace-period cleanups.

 - Remove CONFIG_RCU_FAST_NO_HZ due to lack of valid users. I have asked
   around, posted a blog entry, and sent this series to LKML without
   result.

 - Miscellaneous fixes.

 - RCU callback offloading updates, perhaps most notably Frederic
   Weisbecker's updates allowing CPUs booted in the de-offloaded state
   to be offloaded at runtime.

 - nolibc fixes from Willy Tarreau and Anmar Faizi, but also including
   Mark Brown's addition of gettid().

 - RCU Tasks Trace fixes, including changes that increase the
   scalability of call_rcu_tasks_trace() for the BPF folks (Martin Lau
   and KP Singh).

 - Various fixes including those from Wander Lairson Costa and Li
   Zhijian.

 - Fixes plus addition of tests for the increased call_rcu_tasks_trace()
   scalability.

* tag 'rcu.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (87 commits)
  rcu/nocb: Merge rcu_spawn_cpu_nocb_kthread() and rcu_spawn_one_nocb_kthread()
  rcu/nocb: Allow empty "rcu_nocbs" kernel parameter
  rcu/nocb: Create kthreads on all CPUs if "rcu_nocbs=" or "nohz_full=" are passed
  rcu/nocb: Optimize kthreads and rdp initialization
  rcu/nocb: Prepare nocb_cb_wait() to start with a non-offloaded rdp
  rcu/nocb: Remove rcu_node structure from nocb list when de-offloaded
  rcu-tasks: Use fewer callbacks queues if callback flood ends
  rcu-tasks: Use separate ->percpu_dequeue_lim for callback dequeueing
  rcu-tasks: Use more callback queues if contention encountered
  rcu-tasks: Avoid raw-spinlocked wakeups from call_rcu_tasks_generic()
  rcu-tasks: Count trylocks to estimate call_rcu_tasks() contention
  rcu-tasks: Add rcupdate.rcu_task_enqueue_lim to set initial queueing
  rcu-tasks: Make rcu_barrier_tasks*() handle multiple callback queues
  rcu-tasks: Use workqueues for multiple rcu_tasks_invoke_cbs() invocations
  rcu-tasks: Abstract invocations of callbacks
  rcu-tasks: Abstract checking of callback lists
  rcu-tasks: Add a ->percpu_enqueue_lim to the rcu_tasks structure
  rcu-tasks: Inspect stalled task's trc state in locked state
  rcu-tasks: Use spin_lock_rcu_node() and friends
  rcutorture: Combine n_max_cbs from all kthreads in a callback flood
  ...
This commit is contained in:
Linus Torvalds
2022-01-11 09:29:44 -08:00
parent a229327733 f80fe66c38
commit e7d38f16c2
68 changed files with 1243 additions and 794 deletions
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86
tools/include/nolibc/nolibc.h
View File

@@ -265,12 +265,17 @@ struct stat {
* - arguments are in rdi, rsi, rdx, r10, r8, r9 respectively
* - the system call is performed by calling the syscall instruction
* - syscall return comes in rax
* - rcx and r8..r11 may be clobbered, others are preserved.
* - rcx and r11 are clobbered, others are preserved.
* - the arguments are cast to long and assigned into the target registers
* which are then simply passed as registers to the asm code, so that we
* don't have to experience issues with register constraints.
* - the syscall number is always specified last in order to allow to force
* some registers before (gcc refuses a %-register at the last position).
* - see also x86-64 ABI section A.2 AMD64 Linux Kernel Conventions, A.2.1
* Calling Conventions.
*
* Link x86-64 ABI: https://gitlab.com/x86-psABIs/x86-64-ABI/-/wikis/x86-64-psABI
*
*/
#define my_syscall0(num) \
@@ -280,9 +285,9 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret) \
: "=a"(_ret) \
: "0"(_num) \
: "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
@@ -295,10 +300,10 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret) \
: "=a"(_ret) \
: "r"(_arg1), \
"0"(_num) \
: "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
@@ -312,10 +317,10 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret) \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), \
"0"(_num) \
: "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
@@ -330,10 +335,10 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret) \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), \
"0"(_num) \
: "rcx", "r8", "r9", "r10", "r11", "memory", "cc" \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
@@ -349,10 +354,10 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret), "=r"(_arg4) \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \
"0"(_num) \
: "rcx", "r8", "r9", "r11", "memory", "cc" \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
@@ -369,10 +374,10 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret), "=r"(_arg4), "=r"(_arg5) \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"0"(_num) \
: "rcx", "r9", "r11", "memory", "cc" \
: "rcx", "r11", "memory", "cc" \
); \
_ret; \
})
@@ -390,7 +395,7 @@ struct stat {
\
asm volatile ( \
"syscall\n" \
: "=a" (_ret), "=r"(_arg4), "=r"(_arg5) \
: "=a"(_ret) \
: "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), "r"(_arg5), \
"r"(_arg6), "0"(_num) \
: "rcx", "r11", "memory", "cc" \
@@ -399,17 +404,23 @@ struct stat {
})
/* startup code */
/*
* x86-64 System V ABI mandates:
* 1) %rsp must be 16-byte aligned right before the function call.
* 2) The deepest stack frame should be zero (the %rbp).
*
*/
asm(".section .text\n"
".global _start\n"
"_start:\n"
"pop %rdi\n" // argc (first arg, %rdi)
"mov %rsp, %rsi\n" // argv[] (second arg, %rsi)
"lea 8(%rsi,%rdi,8),%rdx\n" // then a NULL then envp (third arg, %rdx)
"and $-16, %rsp\n" // x86 ABI : esp must be 16-byte aligned when
"sub $8, %rsp\n" // entering the callee
"xor %ebp, %ebp\n" // zero the stack frame
"and $-16, %rsp\n" // x86 ABI : esp must be 16-byte aligned before call
"call main\n" // main() returns the status code, we'll exit with it.
"movzb %al, %rdi\n" // retrieve exit code from 8 lower bits
"mov $60, %rax\n" // NR_exit == 60
"mov %eax, %edi\n" // retrieve exit code (32 bit)
"mov $60, %eax\n" // NR_exit == 60
"syscall\n" // really exit
"hlt\n" // ensure it does not return
"");
@@ -577,20 +588,28 @@ struct sys_stat_struct {
})
/* startup code */
/*
* i386 System V ABI mandates:
* 1) last pushed argument must be 16-byte aligned.
* 2) The deepest stack frame should be set to zero
*
*/
asm(".section .text\n"
".global _start\n"
"_start:\n"
"pop %eax\n" // argc (first arg, %eax)
"mov %esp, %ebx\n" // argv[] (second arg, %ebx)
"lea 4(%ebx,%eax,4),%ecx\n" // then a NULL then envp (third arg, %ecx)
"and $-16, %esp\n" // x86 ABI : esp must be 16-byte aligned when
"xor %ebp, %ebp\n" // zero the stack frame
"and $-16, %esp\n" // x86 ABI : esp must be 16-byte aligned before
"sub $4, %esp\n" // the call instruction (args are aligned)
"push %ecx\n" // push all registers on the stack so that we
"push %ebx\n" // support both regparm and plain stack modes
"push %eax\n"
"call main\n" // main() returns the status code in %eax
"movzbl %al, %ebx\n" // retrieve exit code from lower 8 bits
"movl $1, %eax\n" // NR_exit == 1
"int $0x80\n" // exit now
"mov %eax, %ebx\n" // retrieve exit code (32-bit int)
"movl $1, %eax\n" // NR_exit == 1
"int $0x80\n" // exit now
"hlt\n" // ensure it does not
"");
@@ -774,7 +793,6 @@ asm(".section .text\n"
"and %r3, %r1, $-8\n" // AAPCS : sp must be 8-byte aligned in the
"mov %sp, %r3\n" // callee, an bl doesn't push (lr=pc)
"bl main\n" // main() returns the status code, we'll exit with it.
"and %r0, %r0, $0xff\n" // limit exit code to 8 bits
"movs r7, $1\n" // NR_exit == 1
"svc $0x00\n"
"");
@@ -971,7 +989,6 @@ asm(".section .text\n"
"add x2, x2, x1\n" // + argv
"and sp, x1, -16\n" // sp must be 16-byte aligned in the callee
"bl main\n" // main() returns the status code, we'll exit with it.
"and x0, x0, 0xff\n" // limit exit code to 8 bits
"mov x8, 93\n" // NR_exit == 93
"svc #0\n"
"");
@@ -1176,7 +1193,7 @@ asm(".section .text\n"
"addiu $sp,$sp,-16\n" // the callee expects to save a0..a3 there!
"jal main\n" // main() returns the status code, we'll exit with it.
"nop\n" // delayed slot
"and $a0, $v0, 0xff\n" // limit exit code to 8 bits
"move $a0, $v0\n" // retrieve 32-bit exit code from v0
"li $v0, 4001\n" // NR_exit == 4001
"syscall\n"
".end __start\n"
@@ -1374,7 +1391,6 @@ asm(".section .text\n"
"add a2,a2,a1\n" // + argv
"andi sp,a1,-16\n" // sp must be 16-byte aligned
"call main\n" // main() returns the status code, we'll exit with it.
"andi a0, a0, 0xff\n" // limit exit code to 8 bits
"li a7, 93\n" // NR_exit == 93
"ecall\n"
"");
@@ -1555,6 +1571,12 @@ pid_t sys_getpid(void)
return my_syscall0(__NR_getpid);
}
static __attribute__((unused))
pid_t sys_gettid(void)
{
return my_syscall0(__NR_gettid);
}
static __attribute__((unused))
int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
{
@@ -2013,6 +2035,18 @@ pid_t getpid(void)
return ret;
}
static __attribute__((unused))
pid_t gettid(void)
{
pid_t ret = sys_gettid();
if (ret < 0) {
SET_ERRNO(-ret);
ret = -1;
}
return ret;
}
static __attribute__((unused))
int gettimeofday(struct timeval *tv, struct timezone *tz)
{