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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: [for-linus][PATCH 09/15] ftrace: Use fls() to get the bits for dup_hash()
Date: Tue, 06 Oct 2020 10:34:55 -0400	[thread overview]
Message-ID: <20201006143512.029082917@goodmis.org> (raw)
In-Reply-To: 20201006143446.182666356@goodmis.org

From: Wei Yang <richard.weiyang@linux.alibaba.com>

The effect here is to get the number of bits, lets use fls() to do
this job.

Link: https://lkml.kernel.org/r/20200831031104.23322-3-richard.weiyang@linux.alibaba.com

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 123d520b9261..5633d37d8806 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1370,8 +1370,9 @@ static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
 	/*
 	 * Make the hash size about 1/2 the # found
 	 */
-	for (size /= 2; size; size >>= 1)
-		bits++;
+	bits = fls(size);
+	if (bits)
+		bits--;
 
 	/* Don't allocate too much */
 	if (bits > FTRACE_HASH_MAX_BITS)
-- 
2.28.0



  parent reply	other threads:[~2020-10-06 14:35 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-06 14:34 [for-linus][PATCH 00/15] tracing: Some final updates for 5.10 Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 01/15] ftrace: Fix some typos in comment Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 02/15] tracing: Change STR_VAR_MAX_LEN Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 03/15] tracing: Fix parse_synth_field() error handling Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 04/15] tracing: Save normal string variables Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 05/15] tracing: Add support for dynamic strings to synthetic events Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 06/15] tracing: Add README information for synthetic_events file Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 07/15] selftests/ftrace: Add test case for synthetic event dynamic strings Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 08/15] tracing: Change synthetic event string format to limit printed length Steven Rostedt
2020-10-06 14:34 ` Steven Rostedt [this message]
2020-10-06 14:34 ` [for-linus][PATCH 10/15] ftrace: Simplify the hash calculation Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 11/15] ftrace: Simplify the dyn_ftrace->flags macro Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 12/15] ftrace: Simplify the calculation of page number for ftrace_page->records Steven Rostedt
2020-10-06 14:34 ` [for-linus][PATCH 13/15] ftrace: Format variable declarations of ftrace_allocate_records Steven Rostedt
2020-10-06 14:35 ` [for-linus][PATCH 14/15] ftrace: ftrace_global_list is renamed to ftrace_ops_list Steven Rostedt
2020-10-06 14:35 ` [for-linus][PATCH 15/15] tracing: Remove a pointless assignment Steven Rostedt
2020-10-06 15:01 ` [for-linus][PATCH 00/15] tracing: Some final updates for 5.10 Steven Rostedt

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