005b2a9dc8
-----BEGIN PGP SIGNATURE----- iQJEBAABCAAuFiEEwPw5LcreJtl1+l5K99NY+ylx4KYFAl/YJxsQHGF4Ym9lQGtl cm5lbC5kawAKCRD301j7KXHgpjpyEACBdW+YjenjTbkUPeEXzQgkBkTZUYw3g007 DPcUT1g8PQZXYXlQvBKCvGhhIr7/KVcjepKoowiNQfBNGcIPJTVopW58nzpqAfTQ goI2WYGn5EKFFKBPvtH04cJD/Wo8muXdxynKtqyZbnGGgZjQxPrE259b8dpHjBSR 6L7HHkk0D1oU/5b6h6Ocpg9mc/0iIUCZylySAYY3eGO0JaVPJaXgZSJZYgHxCHll Lb+/y/fXdtm/0PmQ3ko0ev54g3yEWqZIX0NsZW1asrButIy+KLzQ2Mz1xFLFDMag prtIfwb8tzgc4dFPY090C/azjCh5CPpxqYS6FkRwS0p86n6OhkyXrqfily5Hs4/B NC7CBPBSH/j+NKUK7CYZcpTzTpxPjUr9p0anUdlvMJz8FhTb/3YEEZ1UTeWOeHmk Yo5SxnFghLeZZeZ1ok6rdymnVa7WEX12SCLGQX31BB2mld0tNbKb4b+FsBF6OUMk IUaX6OjwDFVRaysC88BQ4hjcIP1HxsViG4/VZDX15gjAAH2Pvb+7tev+lcDcOhjz TCD4GNFspTFzRhh9nT7oxQ679qCh9G9zHbzuIRewnrS6iqvo5SJQB3dR2yrWZRRH ySkQFiHpYOlnLJYv0jg9COlGwo2FUdcvKhCvkjQKKBz48rzW/IC0LwKdRQWZDFk3 FKGzP/NBig== =cadT -----END PGP SIGNATURE----- Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe: "This sits on top of of the core entry/exit and x86 entry branch from the tip tree, which contains the generic and x86 parts of this work. Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL. With that done, we can get rid of JOBCTL_TASK_WORK from task_work and signal.c, and also remove a deadlock work-around in io_uring around knowing that signal based task_work waking is invoked with the sighand wait queue head lock. The motivation for this work is to decouple signal notify based task_work, of which io_uring is a heavy user of, from sighand. The sighand lock becomes a huge contention point, particularly for threaded workloads where it's shared between threads. Even outside of threaded applications it's slower than it needs to be. Roman Gershman <romger@amazon.com> reported that his networked workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all spent hammering on the sighand lock, showing 57% of the CPU time there [1]. There are further cleanups possible on top of this. One example is TIF_PATCH_PENDING, where a patch already exists to use TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more consolidation, but the work stands on its own as well" [1] https://github.com/axboe/liburing/issues/215 * tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits) io_uring: remove 'twa_signal_ok' deadlock work-around kernel: remove checking for TIF_NOTIFY_SIGNAL signal: kill JOBCTL_TASK_WORK io_uring: JOBCTL_TASK_WORK is no longer used by task_work task_work: remove legacy TWA_SIGNAL path sparc: add support for TIF_NOTIFY_SIGNAL riscv: add support for TIF_NOTIFY_SIGNAL nds32: add support for TIF_NOTIFY_SIGNAL ia64: add support for TIF_NOTIFY_SIGNAL h8300: add support for TIF_NOTIFY_SIGNAL c6x: add support for TIF_NOTIFY_SIGNAL alpha: add support for TIF_NOTIFY_SIGNAL xtensa: add support for TIF_NOTIFY_SIGNAL arm: add support for TIF_NOTIFY_SIGNAL microblaze: add support for TIF_NOTIFY_SIGNAL hexagon: add support for TIF_NOTIFY_SIGNAL csky: add support for TIF_NOTIFY_SIGNAL openrisc: add support for TIF_NOTIFY_SIGNAL sh: add support for TIF_NOTIFY_SIGNAL um: add support for TIF_NOTIFY_SIGNAL ...
103 lines
3.3 KiB
C
103 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* S390 version
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* Copyright IBM Corp. 2002, 2006
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*/
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#ifndef _ASM_THREAD_INFO_H
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#define _ASM_THREAD_INFO_H
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#include <linux/bits.h>
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/*
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* General size of kernel stacks
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*/
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#ifdef CONFIG_KASAN
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#define THREAD_SIZE_ORDER 4
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#else
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#define THREAD_SIZE_ORDER 2
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#endif
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#define BOOT_STACK_SIZE (PAGE_SIZE << 2)
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#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
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#ifndef __ASSEMBLY__
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#include <asm/lowcore.h>
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#include <asm/page.h>
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#define STACK_INIT_OFFSET \
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(THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs))
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/*
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* low level task data that entry.S needs immediate access to
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* - this struct should fit entirely inside of one cache line
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* - this struct shares the supervisor stack pages
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* - if the contents of this structure are changed, the assembly constants must also be changed
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*/
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struct thread_info {
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unsigned long flags; /* low level flags */
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};
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/*
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* macros/functions for gaining access to the thread information structure
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*/
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#define INIT_THREAD_INFO(tsk) \
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{ \
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.flags = 0, \
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}
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void arch_release_task_struct(struct task_struct *tsk);
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int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
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void arch_setup_new_exec(void);
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#define arch_setup_new_exec arch_setup_new_exec
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#endif
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/*
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* thread information flags bit numbers
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*/
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/* _TIF_WORK bits */
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#define TIF_NOTIFY_RESUME 0 /* callback before returning to user */
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#define TIF_SIGPENDING 1 /* signal pending */
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#define TIF_NEED_RESCHED 2 /* rescheduling necessary */
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#define TIF_UPROBE 3 /* breakpointed or single-stepping */
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#define TIF_GUARDED_STORAGE 4 /* load guarded storage control block */
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#define TIF_PATCH_PENDING 5 /* pending live patching update */
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#define TIF_PGSTE 6 /* New mm's will use 4K page tables */
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#define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */
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#define TIF_ISOLATE_BP 8 /* Run process with isolated BP */
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#define TIF_ISOLATE_BP_GUEST 9 /* Run KVM guests with isolated BP */
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#define TIF_31BIT 16 /* 32bit process */
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#define TIF_MEMDIE 17 /* is terminating due to OOM killer */
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#define TIF_RESTORE_SIGMASK 18 /* restore signal mask in do_signal() */
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#define TIF_SINGLE_STEP 19 /* This task is single stepped */
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#define TIF_BLOCK_STEP 20 /* This task is block stepped */
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#define TIF_UPROBE_SINGLESTEP 21 /* This task is uprobe single stepped */
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/* _TIF_TRACE bits */
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#define TIF_SYSCALL_TRACE 24 /* syscall trace active */
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#define TIF_SYSCALL_AUDIT 25 /* syscall auditing active */
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#define TIF_SECCOMP 26 /* secure computing */
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#define TIF_SYSCALL_TRACEPOINT 27 /* syscall tracepoint instrumentation */
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#define _TIF_NOTIFY_RESUME BIT(TIF_NOTIFY_RESUME)
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#define _TIF_NOTIFY_SIGNAL BIT(TIF_NOTIFY_SIGNAL)
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#define _TIF_SIGPENDING BIT(TIF_SIGPENDING)
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#define _TIF_NEED_RESCHED BIT(TIF_NEED_RESCHED)
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#define _TIF_UPROBE BIT(TIF_UPROBE)
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#define _TIF_GUARDED_STORAGE BIT(TIF_GUARDED_STORAGE)
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#define _TIF_PATCH_PENDING BIT(TIF_PATCH_PENDING)
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#define _TIF_ISOLATE_BP BIT(TIF_ISOLATE_BP)
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#define _TIF_ISOLATE_BP_GUEST BIT(TIF_ISOLATE_BP_GUEST)
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#define _TIF_31BIT BIT(TIF_31BIT)
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#define _TIF_SINGLE_STEP BIT(TIF_SINGLE_STEP)
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#define _TIF_SYSCALL_TRACE BIT(TIF_SYSCALL_TRACE)
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#define _TIF_SYSCALL_AUDIT BIT(TIF_SYSCALL_AUDIT)
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#define _TIF_SECCOMP BIT(TIF_SECCOMP)
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#define _TIF_SYSCALL_TRACEPOINT BIT(TIF_SYSCALL_TRACEPOINT)
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#endif /* _ASM_THREAD_INFO_H */
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