From: guoren@kernel.org
To: paul.walmsley@sifive.com, palmer@dabbelt.com, guoren@kernel.org,
panqinglin2020@iscas.ac.cn, bjorn@rivosinc.com,
conor.dooley@microchip.com, leobras@redhat.com,
peterz@infradead.org, anup@brainfault.org, keescook@chromium.org,
wuwei2016@iscas.ac.cn, xiaoguang.xing@sophgo.com,
chao.wei@sophgo.com, unicorn_wang@outlook.com, uwu@icenowy.me,
jszhang@kernel.org, wefu@redhat.com, atishp@atishpatra.org
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
Guo Ren <guoren@linux.alibaba.com>
Subject: [PATCH V12 12/14] RISC-V: paravirt: pvqspinlock: Add nopvspin kernel parameter
Date: Mon, 25 Dec 2023 07:58:45 -0500 [thread overview]
Message-ID: <20231225125847.2778638-13-guoren@kernel.org> (raw)
In-Reply-To: <20231225125847.2778638-1-guoren@kernel.org>
From: Guo Ren <guoren@linux.alibaba.com>
Disables the qspinlock slow path using PV optimizations which
allow the hypervisor to 'idle' the guest on lock contention.
Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
Documentation/admin-guide/kernel-parameters.txt | 2 +-
arch/riscv/kernel/qspinlock_paravirt.c | 13 +++++++++++++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b7794c96d91e..4aff81d741e2 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3927,7 +3927,7 @@
as generic guest with no PV drivers. Currently support
XEN HVM, KVM, HYPER_V and VMWARE guest.
- nopvspin [X86,XEN,KVM]
+ nopvspin [X86,XEN,KVM,RISC-V]
Disables the qspinlock slow path using PV optimizations
which allow the hypervisor to 'idle' the guest on lock
contention.
diff --git a/arch/riscv/kernel/qspinlock_paravirt.c b/arch/riscv/kernel/qspinlock_paravirt.c
index 7d1b99412222..4b04c93c4b9b 100644
--- a/arch/riscv/kernel/qspinlock_paravirt.c
+++ b/arch/riscv/kernel/qspinlock_paravirt.c
@@ -43,8 +43,21 @@ EXPORT_STATIC_CALL(pv_queued_spin_lock_slowpath);
DEFINE_STATIC_CALL(pv_queued_spin_unlock, native_queued_spin_unlock);
EXPORT_STATIC_CALL(pv_queued_spin_unlock);
+static bool nopvspin __initdata;
+static __init int parse_nopvspin(char *arg)
+{
+ nopvspin = true;
+ return 0;
+}
+early_param("nopvspin", parse_nopvspin);
+
void __init pv_qspinlock_init(void)
{
+ if (nopvspin) {
+ pr_info("PV qspinlocks disabled\n");
+ return;
+ }
+
if (num_possible_cpus() == 1)
return;
--
2.40.1
next prev parent reply other threads:[~2023-12-25 13:00 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-25 12:58 [PATCH V12 00/14] riscv: Add Native/Paravirt qspinlock support guoren
2023-12-25 12:58 ` [PATCH V12 01/14] asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock guoren
2023-12-25 12:58 ` [PATCH V12 02/14] asm-generic: ticket-lock: Add separate ticket-lock.h guoren
2023-12-25 12:58 ` [PATCH V12 03/14] riscv: errata: Move errata vendor func-id into vendorid_list.h guoren
2024-01-04 4:00 ` Leonardo Bras
2023-12-25 12:58 ` [PATCH V12 04/14] riscv: qspinlock: errata: Add ERRATA_THEAD_WRITE_ONCE fixup guoren
2023-12-25 12:58 ` [PATCH V12 05/14] riscv: qspinlock: Add basic queued_spinlock support guoren
2023-12-25 12:58 ` [PATCH V12 06/14] riscv: qspinlock: Introduce combo spinlock guoren
2024-01-04 4:56 ` Leonardo Bras
2023-12-25 12:58 ` [PATCH V12 07/14] riscv: qspinlock: Add virt_spin_lock() support for VM guest guoren
2024-01-04 5:06 ` Leonardo Bras
2023-12-25 12:58 ` [PATCH V12 08/14] riscv: qspinlock: Force virt_spin_lock for KVM guests guoren
2024-01-04 5:11 ` Leonardo Bras
2023-12-25 12:58 ` [PATCH V12 09/14] RISC-V: paravirt: Add pvqspinlock KVM backend guoren
2023-12-25 12:58 ` [PATCH V12 10/14] RISC-V: paravirt: Add pvqspinlock frontend skeleton guoren
2023-12-25 12:58 ` [PATCH V12 11/14] RISC-V: paravirt: pvqspinlock: Add SBI implementation guoren
2023-12-25 12:58 ` guoren [this message]
2023-12-25 12:58 ` [PATCH V12 13/14] RISC-V: paravirt: pvqspinlock: Add kconfig entry guoren
2023-12-25 12:58 ` [PATCH V12 14/14] RISC-V: paravirt: pvqspinlock: Add trace point for pv_kick/wait guoren
2023-12-26 0:35 ` [PATCH V12 00/14] riscv: Add Native/Paravirt qspinlock support Guo Ren
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231225125847.2778638-13-guoren@kernel.org \
--to=guoren@kernel.org \
--cc=anup@brainfault.org \
--cc=atishp@atishpatra.org \
--cc=bjorn@rivosinc.com \
--cc=chao.wei@sophgo.com \
--cc=conor.dooley@microchip.com \
--cc=guoren@linux.alibaba.com \
--cc=jszhang@kernel.org \
--cc=keescook@chromium.org \
--cc=kvm@vger.kernel.org \
--cc=leobras@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=panqinglin2020@iscas.ac.cn \
--cc=paul.walmsley@sifive.com \
--cc=peterz@infradead.org \
--cc=unicorn_wang@outlook.com \
--cc=uwu@icenowy.me \
--cc=virtualization@lists.linux-foundation.org \
--cc=wefu@redhat.com \
--cc=wuwei2016@iscas.ac.cn \
--cc=xiaoguang.xing@sophgo.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).