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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Alexander Potapenko <glider@google.com>
Subject: [RFC patch 14/41] latency_top: Remove the ULONG_MAX stack trace hackery
Date: Wed, 10 Apr 2019 12:28:08 +0200
Message-ID: <20190410103644.853527514@linutronix.de> (raw)
In-Reply-To: <20190410102754.387743324@linutronix.de>

No architecture terminates the stack trace with ULONG_MAX anymore. The
consumer terminates on the first zero entry or at the number of entries, so
no functional change.

Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 fs/proc/base.c      |    3 +--
 kernel/latencytop.c |   12 ++++++------
 2 files changed, 7 insertions(+), 8 deletions(-)

--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -489,10 +489,9 @@ static int lstats_show_proc(struct seq_f
 				   lr->count, lr->time, lr->max);
 			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 				unsigned long bt = lr->backtrace[q];
+
 				if (!bt)
 					break;
-				if (bt == ULONG_MAX)
-					break;
 				seq_printf(m, " %ps", (void *)bt);
 			}
 			seq_putc(m, '\n');
--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -120,8 +120,8 @@ account_global_scheduler_latency(struct
 				break;
 			}
 
-			/* 0 and ULONG_MAX entries mean end of backtrace: */
-			if (record == 0 || record == ULONG_MAX)
+			/* 0 entry marks end of backtrace: */
+			if (!record)
 				break;
 		}
 		if (same) {
@@ -210,8 +210,8 @@ void __sched
 				break;
 			}
 
-			/* 0 and ULONG_MAX entries mean end of backtrace: */
-			if (record == 0 || record == ULONG_MAX)
+			/* 0 entry is end of backtrace */
+			if (!record)
 				break;
 		}
 		if (same) {
@@ -252,10 +252,10 @@ static int lstats_show(struct seq_file *
 				   lr->count, lr->time, lr->max);
 			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
 				unsigned long bt = lr->backtrace[q];
+
 				if (!bt)
 					break;
-				if (bt == ULONG_MAX)
-					break;
+
 				seq_printf(m, " %ps", (void *)bt);
 			}
 			seq_puts(m, "\n");



  parent reply index

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-10 10:27 [RFC patch 00/41] stacktrace: Avoid the pointless redirection through struct stack_trace Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 01/41] um/stacktrace: Remove the pointless ULONG_MAX marker Thomas Gleixner
2019-04-14 20:34   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 02/41] x86/stacktrace: " Thomas Gleixner
2019-04-14 20:34   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 03/41] arm/stacktrace: " Thomas Gleixner
2019-04-14 20:35   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 04/41] sh/stacktrace: " Thomas Gleixner
2019-04-14 20:36   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:27 ` [RFC patch 05/41] unicore32/stacktrace: " Thomas Gleixner
2019-04-14 20:36   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 06/41] riscv/stacktrace: " Thomas Gleixner
2019-04-14 20:37   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 07/41] arm64/stacktrace: " Thomas Gleixner
2019-04-14 20:38   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 08/41] parisc/stacktrace: " Thomas Gleixner
2019-04-14 20:38   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 09/41] s390/stacktrace: " Thomas Gleixner
2019-04-14 20:39   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 10/41] lockdep: Remove the ULONG_MAX stack trace hackery Thomas Gleixner
2019-04-14 20:40   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 11/41] mm/slub: " Thomas Gleixner
2019-04-14 20:40   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 12/41] mm/page_owner: " Thomas Gleixner
2019-04-14 20:41   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 13/41] mm/kasan: " Thomas Gleixner
2019-04-10 11:31   ` Dmitry Vyukov
2019-04-14 20:42   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` Thomas Gleixner [this message]
2019-04-14 20:42   ` [tip:core/stacktrace] latency_top: " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 15/41] drm: " Thomas Gleixner
2019-04-14 20:43   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 16/41] tracing: " Thomas Gleixner
2019-04-11  2:34   ` Josh Poimboeuf
2019-04-11  3:07     ` Steven Rostedt
2019-04-14 20:44   ` [tip:core/stacktrace] " tip-bot for Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 17/41] tracing: Make stack_trace_print() static and rename it Thomas Gleixner
2019-04-10 12:47   ` Steven Rostedt
2019-04-11  0:19     ` AKASHI Takahiro
2019-04-10 10:28 ` [RFC patch 18/41] stacktrace: Provide helpers for common stack trace operations Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 19/41] lib/stackdepot: Provide functions which operate on plain storage arrays Thomas Gleixner
2019-04-10 13:39   ` Alexander Potapenko
2019-04-10 10:28 ` [RFC patch 20/41] backtrace-test: Simplify stack trace handling Thomas Gleixner
2019-04-11  2:47   ` Josh Poimboeuf
2019-04-10 10:28 ` [RFC patch 21/41] proc: Simplify task stack retrieval Thomas Gleixner
2019-04-14 14:49   ` Alexey Dobriyan
2019-04-10 10:28 ` [RFC patch 22/41] latency_top: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 23/41] mm/slub: Simplify stack trace retrieval Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 24/41] mm/kmemleak: Simplify stacktrace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 25/41] mm/kasan: " Thomas Gleixner
2019-04-10 11:33   ` Dmitry Vyukov
2019-04-11  2:55   ` Josh Poimboeuf
2019-04-14 16:54     ` Thomas Gleixner
2019-04-14 17:00       ` Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 26/41] mm/page_owner: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 27/41] fault-inject: Simplify stacktrace retrieval Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 28/41] dma/debug: Simplify stracktrace retrieval Thomas Gleixner
2019-04-10 11:08   ` Christoph Hellwig
2019-04-10 12:08     ` Thomas Gleixner
2019-04-10 12:25       ` Steven Rostedt
2019-04-11 17:21       ` Christoph Hellwig
2019-04-11 17:36         ` Steven Rostedt
2019-04-11 17:44           ` Christoph Hellwig
2019-04-11  3:02   ` Josh Poimboeuf
2019-04-11  3:09     ` Steven Rostedt
2019-04-10 10:28 ` [RFC patch 29/41] btrfs: ref-verify: Simplify stack trace retrieval Thomas Gleixner
2019-04-10 11:31   ` Johannes Thumshirn
2019-04-10 12:05     ` Thomas Gleixner
2019-04-10 12:38       ` Johannes Thumshirn
2019-04-10 12:50   ` David Sterba
2019-04-10 13:47   ` Alexander Potapenko
2019-04-10 10:28 ` [RFC patch 30/41] dm bufio: " Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 31/41] dm persistent data: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 32/41] drm: Simplify stacktrace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 33/41] lockdep: Remove unused trace argument from print_circular_bug() Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 34/41] lockdep: Move stack trace logic into check_prev_add() Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 35/41] lockdep: Simplify stack trace handling Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 36/41] tracing: Simplify stacktrace retrieval in histograms Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 37/41] tracing: Use percpu stack trace buffer more intelligently Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 38/41] tracing: Make ftrace_trace_userstack() static and conditional Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 39/41] tracing: Simplify stack trace retrieval Thomas Gleixner
2019-04-10 10:28 ` [RFC patch 40/41] stacktrace: Remove obsolete functions Thomas Gleixner
2019-04-11  3:33   ` Josh Poimboeuf
2019-04-11  9:13     ` Peter Zijlstra
2019-04-11 13:00     ` Josh Poimboeuf
2019-04-10 10:28 ` [RFC patch 41/41] lib/stackdepot: " Thomas Gleixner
2019-04-10 13:49   ` Alexander Potapenko
2019-04-10 11:49 ` [RFC patch 00/41] stacktrace: Avoid the pointless redirection through struct stack_trace Peter Zijlstra

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