Commit 3f020399 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull scheduler updates from Ingo Molnar:
 "Core facilities:

   - Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which
     optimizes fair-class preemption by delaying preemption requests to
     the tick boundary, while working as full preemption for
     RR/FIFO/DEADLINE classes. (Peter Zijlstra)
        - x86: Enable Lazy preemption (Peter Zijlstra)
        - riscv: Enable Lazy preemption (Jisheng Zhang)

   - Initialize idle tasks only once (Thomas Gleixner)

   - sched/ext: Remove sched_fork() hack (Thomas Gleixner)

  Fair scheduler:

   - Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)

  Idle loop:

   - Optimize the generic idle loop by removing unnecessary memory
     barrier (Zhongqiu Han)

  RSEQ:

   - Improve cache locality of RSEQ concurrency IDs for intermittent
     workloads (Mathieu Desnoyers)

  Waitqueues:

   - Make wake_up_{bit,var} less fragile (Neil Brown)

  PSI:

   - Pass enqueue/dequeue flags to psi callbacks directly (Johannes
     Weiner)

  Preparatory patches for proxy execution:

   - Add move_queued_task_locked helper (Connor O'Brien)

   - Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)

   - Split out __schedule() deactivate task logic into a helper (John
     Stultz)

   - Split scheduler and execution contexts (Peter Zijlstra)

   - Make mutex::wait_lock irq safe (Juri Lelli)

   - Expose __mutex_owner() (Juri Lelli)

   - Remove wakeups from under mutex::wait_lock (Peter Zijlstra)

  Misc fixes and cleanups:

   - Remove unused __HAVE_THREAD_FUNCTIONS hook support (David
     Disseldorp)

   - Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej
     Siewior)

   - Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)

   - remove the DOUBLE_TICK feature (Huang Shijie)

   - fix the comment for PREEMPT_SHORT (Huang Shijie)

   - Fix unnused variable warning (Christian Loehle)

   - No PREEMPT_RT=y for all{yes,mod}config"

* tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  sched, x86: Update the comment for TIF_NEED_RESCHED_LAZY.
  sched: No PREEMPT_RT=y for all{yes,mod}config
  riscv: add PREEMPT_LAZY support
  sched, x86: Enable Lazy preemption
  sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT
  sched: Add Lazy preemption model
  sched: Add TIF_NEED_RESCHED_LAZY infrastructure
  sched/ext: Remove sched_fork() hack
  sched: Initialize idle tasks only once
  sched: psi: pass enqueue/dequeue flags to psi callbacks directly
  sched/uclamp: Fix unnused variable warning
  sched: Split scheduler and execution contexts
  sched: Split out __schedule() deactivate task logic into a helper
  sched: Consolidate pick_*_task to task_is_pushable helper
  sched: Add move_queued_task_locked helper
  locking/mutex: Expose __mutex_owner()
  locking/mutex: Make mutex::wait_lock irq safe
  locking/mutex: Remove wakeups from under mutex::wait_lock
  sched: Improve cache locality of RSEQ concurrency IDs for intermittent workloads
  sched: idle: Optimize the generic idle loop by removing needless memory barrier
  ...
parents f41dac3e 771d271b

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ config RISCV 
	select ARCH_HAS_MMIOWB

	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	select ARCH_HAS_PMEM_API

	select ARCH_HAS_PREEMPT_LAZY

	select ARCH_HAS_PREPARE_SYNC_CORE_CMD

	select ARCH_HAS_PTE_DEVMAP if 64BIT && MMU

	select ARCH_HAS_PTE_SPECIAL

arch/riscv/include/asm/thread_info.h

+6 −4
Original line number Diff line number Diff line
@@ -107,9 +107,10 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); 
 * - pending work-to-be-done flags are in lowest half-word

 * - other flags in upper half-word(s)

 */

#define TIF_NOTIFY_RESUME	1	/* callback before returning to user */

#define TIF_SIGPENDING		2	/* signal pending */

#define TIF_NEED_RESCHED	3	/* rescheduling necessary */

#define TIF_NEED_RESCHED	0	/* rescheduling necessary */

#define TIF_NEED_RESCHED_LAZY	1       /* Lazy rescheduling needed */

#define TIF_NOTIFY_RESUME	2	/* callback before returning to user */

#define TIF_SIGPENDING		3	/* signal pending */

#define TIF_RESTORE_SIGMASK	4	/* restore signal mask in do_signal() */

#define TIF_MEMDIE		5	/* is terminating due to OOM killer */

#define TIF_NOTIFY_SIGNAL	9	/* signal notifications exist */
@@ -117,9 +118,10 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); 
#define TIF_32BIT		11	/* compat-mode 32bit process */

#define TIF_RISCV_V_DEFER_RESTORE	12 /* restore Vector before returing to user */



#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)

#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)

#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)

#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)

#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)

#define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)

#define _TIF_UPROBE		(1 << TIF_UPROBE)

#define _TIF_RISCV_V_DEFER_RESTORE	(1 << TIF_RISCV_V_DEFER_RESTORE)

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ config X86 
	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS

	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

	select ARCH_HAS_PMEM_API		if X86_64

	select ARCH_HAS_PREEMPT_LAZY

	select ARCH_HAS_PTE_DEVMAP		if X86_64

	select ARCH_HAS_PTE_SPECIAL

	select ARCH_HAS_HW_PTE_YOUNG

arch/x86/include/asm/thread_info.h

+4 −2
Original line number Diff line number Diff line
@@ -87,8 +87,9 @@ struct thread_info { 
#define TIF_NOTIFY_RESUME	1	/* callback before returning to user */

#define TIF_SIGPENDING		2	/* signal pending */

#define TIF_NEED_RESCHED	3	/* rescheduling necessary */

#define TIF_SINGLESTEP		4	/* reenable singlestep on user return*/

#define TIF_SSBD		5	/* Speculative store bypass disable */

#define TIF_NEED_RESCHED_LAZY	4	/* Lazy rescheduling needed */

#define TIF_SINGLESTEP		5	/* reenable singlestep on user return*/

#define TIF_SSBD		6	/* Speculative store bypass disable */

#define TIF_SPEC_IB		9	/* Indirect branch speculation mitigation */

#define TIF_SPEC_L1D_FLUSH	10	/* Flush L1D on mm switches (processes) */

#define TIF_USER_RETURN_NOTIFY	11	/* notify kernel of userspace return */
@@ -110,6 +111,7 @@ struct thread_info { 
#define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)

#define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)

#define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)

#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)

#define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)

#define _TIF_SSBD		(1 << TIF_SSBD)

#define _TIF_SPEC_IB		(1 << TIF_SPEC_IB)

fs/exec.c

+1 −1
Original line number Diff line number Diff line
@@ -990,7 +990,7 @@ static int exec_mmap(struct mm_struct *mm) 
	active_mm = tsk->active_mm;

	tsk->active_mm = mm;

	tsk->mm = mm;

	mm_init_cid(mm);

	mm_init_cid(mm, tsk);

	/*

	 * This prevents preemption while active_mm is being loaded and

	 * it and mm are being updated, which could cause problems for