+ kallsyms-unroll-24-bit-sequence-reconstruction-in-get_symbol_seq.patch added to mm-nonmm-unstable branch

+ kallsyms-unroll-24-bit-sequence-reconstruction-in-get_symbol_seq.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: kallsyms: unroll 24-bit sequence reconstruction in get_symbol_seq()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     kallsyms-unroll-24-bit-sequence-reconstruction-in-get_symbol_seq.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kallsyms-unroll-24-bit-sequence-reconstruction-in-get_symbol_seq.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Jim Cromie <jim.cromie@gmail.com>
Subject: kallsyms: unroll 24-bit sequence reconstruction in get_symbol_seq()
Date: Tue, 29 Sep 2026 12:07:32 -0600

kallsyms_seqs_of_names[] stores 3-byte big-endian sequence indices that
map alphabetical symbol positions to address-ordered symbol records. 
Currently, get_symbol_seq() reconstructs each 24-bit integer using a
3-iteration for-loop that shifts and bitwise-ORs each byte sequentially. 
During binary search in kallsyms_lookup_names() and duplicate boundary
scans, this loop introduces branch and loop overhead on the hot lookup
path.

Mark get_symbol_seq() as static inline and unroll the 3-byte extraction
into direct byte shifts: (p[0] << 16) | (p[1] << 8) | p[2].  This
eliminates loop induction variable maintenance and allows the compiler to
generate direct loads and constant shifts.

Link: https://lore.kernel.org/20260929-ksyms-tune-v7-3-be568ceef41e@gmail.com
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: David Laight <david.laight.linux@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
---

 kernel/kallsyms.c |    9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

--- a/kernel/kallsyms.c~kallsyms-unroll-24-bit-sequence-reconstruction-in-get_symbol_seq
+++ a/kernel/kallsyms.c
@@ -185,14 +185,11 @@ unsigned long kallsyms_sym_address(int i
 	return (unsigned long)offset_to_ptr(kallsyms_offsets + idx);
 }
 
-static unsigned int get_symbol_seq(int index)
+static inline unsigned int get_symbol_seq(int index)
 {
-	unsigned int i, seq = 0;
+	const u8 *p = &kallsyms_seqs_of_names[3 * index];
 
-	for (i = 0; i < 3; i++)
-		seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i];
-
-	return seq;
+	return (p[0] << 16) | (p[1] << 8) | p[2];
 }
 
 static int kallsyms_lookup_names(const char *name,
_

Patches currently in -mm which might be from jim.cromie@gmail.com are

kallsyms-match-compressed-tokens-on-the-fly-during-binary-search.patch
kallsyms-increase-marker-density-to-16-1-to-accelerate-lookups.patch
kallsyms-unroll-24-bit-sequence-reconstruction-in-get_symbol_seq.patch