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From: Boqun Feng <boqun@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Catalin Marinas" <catalin.marinas@arm.com>,
	"Will Deacon" <will@kernel.org>,
	"Jonas Bonn" <jonas@southpole.se>,
	"Stefan Kristiansson" <stefan.kristiansson@saunalahti.fi>,
	"Stafford Horne" <shorne@gmail.com>,
	"Heiko Carstens" <hca@linux.ibm.com>,
	"Vasily Gorbik" <gor@linux.ibm.com>,
	"Alexander Gordeev" <agordeev@linux.ibm.com>,
	"Christian Borntraeger" <borntraeger@linux.ibm.com>,
	"Sven Schnelle" <svens@linux.ibm.com>,
	"Thomas Gleixner" <tglx@kernel.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Juri Lelli" <juri.lelli@redhat.com>,
	"Vincent Guittot" <vincent.guittot@linaro.org>,
	"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Ben Segall" <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>,
	"Valentin Schneider" <vschneid@redhat.com>,
	"K Prateek Nayak" <kprateek.nayak@amd.com>,
	"Boqun Feng" <boqun@kernel.org>,
	"Waiman Long" <longman@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Eduard Zingerman" <eddyz87@gmail.com>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Martin KaFai Lau" <martin.lau@linux.dev>,
	"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
	"Song Liu" <song@kernel.org>,
	"Yonghong Song" <yonghong.song@linux.dev>,
	"Jiri Olsa" <jolsa@kernel.org>, "Shuah Khan" <shuah@kernel.org>,
	"Miguel Ojeda" <ojeda@kernel.org>, "Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Jinjie Ruan" <ruanjinjie@huawei.com>,
	"Lyude Paul" <lyude@redhat.com>, "Thomas Huth" <thuth@redhat.com>,
	"Sohil Mehta" <sohil.mehta@intel.com>,
	"Xin Li (Intel)" <xin@zytor.com>,
	"Pawan Gupta" <pawan.kumar.gupta@linux.intel.com>,
	"Nikunj A Dadhania" <nikunj@amd.com>,
	"Joel Fernandes" <joelagnelf@nvidia.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Yury Norov" <ynorov@nvidia.com>,
	"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
	linux-kernel@vger.kernel.org, linux-openrisc@vger.kernel.org,
	linux-s390@vger.kernel.org, linux-arch@vger.kernel.org,
	bpf@vger.kernel.org, linux-kselftest@vger.kernel.org,
	rust-for-linux@vger.kernel.org, "Onur Özkan" <work@onurozkan.dev>,
	"Daniel Almeida" <daniel.almeida@collabora.com>,
	"Boqun Feng" <boqun.feng@gmail.com>
Subject: [PATCH v2 02/12] preempt: Introduce HARDIRQ_DISABLE_BITS
Date: Tue, 26 May 2026 08:21:38 -0700	[thread overview]
Message-ID: <20260526152148.30514-3-boqun@kernel.org> (raw)
In-Reply-To: <20260526152148.30514-1-boqun@kernel.org>

From: Boqun Feng <boqun.feng@gmail.com>

In order to support preempt_disable()-like interrupt disabling, that is,
using part of preempt_count() to track interrupt disabling nested level,
change the preempt_count() layout to contain 8-bit HARDIRQ_DISABLE
count.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Link: https://patch.msgid.link/20260121223933.1568682-2-lyude@redhat.com
---
 include/linux/preempt.h                        | 16 +++++++++++-----
 tools/testing/selftests/bpf/bpf_experimental.h |  5 ++++-
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 586f96688325..e2d3079d3f5f 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -17,8 +17,9 @@
  *
  * - bits 0-7 are the preemption count (max preemption depth: 256)
  * - bits 8-15 are the softirq count (max # of softirqs: 256)
- * - bits 16-19 are the hardirq count (max # of hardirqs: 16)
- * - bit 20 is the NMI flag (no nesting count, tracked separately)
+ * - bits 16-23 are the hardirq disable count (max # of hardirq disable: 256)
+ * - bits 24-27 are the hardirq count (max # of hardirqs: 16)
+ * - bit 28 is the NMI flag (no nesting count, tracked separately)
  *
  * The hardirq count could in theory be the same as the number of
  * interrupts in the system, but we run all interrupt handlers with
@@ -31,29 +32,34 @@
  *
  *         PREEMPT_MASK:	0x000000ff
  *         SOFTIRQ_MASK:	0x0000ff00
- *         HARDIRQ_MASK:	0x000f0000
- *             NMI_MASK:	0x00100000
+ * HARDIRQ_DISABLE_MASK:	0x00ff0000
+ *         HARDIRQ_MASK:	0x0f000000
+ *             NMI_MASK:	0x10000000
  * PREEMPT_NEED_RESCHED:	0x80000000
  */
 #define PREEMPT_BITS	8
 #define SOFTIRQ_BITS	8
+#define HARDIRQ_DISABLE_BITS	8
 #define HARDIRQ_BITS	4
 #define NMI_BITS	1
 
 #define PREEMPT_SHIFT	0
 #define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
-#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)
+#define HARDIRQ_DISABLE_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)
+#define HARDIRQ_SHIFT	(HARDIRQ_DISABLE_SHIFT + HARDIRQ_DISABLE_BITS)
 #define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)
 
 #define __IRQ_MASK(x)	((1UL << (x))-1)
 
 #define PREEMPT_MASK	(__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
 #define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
+#define HARDIRQ_DISABLE_MASK	(__IRQ_MASK(HARDIRQ_DISABLE_BITS) << HARDIRQ_DISABLE_SHIFT)
 #define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
 #define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)
 
 #define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)
 #define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)
+#define HARDIRQ_DISABLE_OFFSET	(1UL << HARDIRQ_DISABLE_SHIFT)
 #define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)
 #define NMI_OFFSET	(1UL << NMI_SHIFT)
 
diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 2d4256ff471f..a811b080db02 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -448,17 +448,20 @@ extern int bpf_cgroup_read_xattr(struct cgroup *cgroup, const char *name__str,
 
 #define PREEMPT_BITS	8
 #define SOFTIRQ_BITS	8
+#define HARDIRQ_DISABLE_BITS	8
 #define HARDIRQ_BITS	4
 #define NMI_BITS	1
 
 #define PREEMPT_SHIFT	0
 #define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
-#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)
+#define HARDIRQ_DISABLE_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)
+#define HARDIRQ_SHIFT	(HARDIRQ_DISABLE_SHIFT + HARDIRQ_DISABLE_BITS)
 #define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)
 
 #define __IRQ_MASK(x)	((1UL << (x))-1)
 
 #define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
+#define HARDIRQ_DISABLE_MASK	(__IRQ_MASK(HARDIRQ_DISABLE_BITS) << HARDIRQ_DISABLE_SHIFT)
 #define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
 #define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)
 
-- 
2.50.1 (Apple Git-155)


  parent reply	other threads:[~2026-05-26 15:22 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-26 15:21 [PATCH v2 00/12] Refcounted interrupt disable and SpinLockIrq for rust (Part 1) Boqun Feng
2026-05-26 15:21 ` [PATCH v2 01/12] preempt: Track NMI nesting to separate per-CPU counter Boqun Feng
2026-05-26 15:21 ` Boqun Feng [this message]
2026-05-26 15:21 ` [PATCH v2 03/12] preempt: Introduce __preempt_count_{sub, add}_return() Boqun Feng
2026-05-26 15:21 ` [PATCH v2 04/12] openrisc: Include <linux/cpumask.h> in smp.h Boqun Feng
2026-05-26 15:21 ` [PATCH v2 05/12] irq & spin_lock: Add counted interrupt disabling/enabling Boqun Feng
2026-05-26 16:19   ` bot+bpf-ci
2026-05-28 10:43   ` Peter Zijlstra
2026-05-28 14:31     ` Boqun Feng
2026-05-26 15:21 ` [PATCH v2 06/12] irq: Add KUnit test for refcounted interrupt enable/disable Boqun Feng
2026-05-26 15:21 ` [PATCH v2 07/12] locking: Switch to _irq_{disable,enable}() variants in cleanup guards Boqun Feng
2026-05-28 10:45   ` Peter Zijlstra
2026-05-28 14:31     ` Boqun Feng
2026-05-26 15:21 ` [PATCH v2 08/12] sched: Remove the unused preempt_offset parameter of __cant_sleep() Boqun Feng
2026-05-26 15:21 ` [PATCH v2 09/12] sched: Avoid signed comparison of preempt_count() in __cant_migrate() Boqun Feng
2026-05-26 15:21 ` [PATCH v2 10/12] preempt: Introduce HAS_SEPARATE_PREEMPT_RESCHED_BITS Boqun Feng
2026-05-26 15:21 ` [PATCH v2 11/12] arm64: sched/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS Boqun Feng
2026-05-28 10:50   ` Peter Zijlstra
2026-05-26 15:21 ` [PATCH v2 12/12] s390/preempt: " Boqun Feng
2026-05-28 10:53   ` Peter Zijlstra
2026-05-28 14:41     ` Boqun Feng
2026-05-28 15:18       ` Heiko Carstens
2026-05-27 16:18 ` [PATCH v2 00/12] Refcounted interrupt disable and SpinLockIrq for rust (Part 1) Peter Zijlstra
2026-05-27 16:33   ` Boqun Feng

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