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| author | Sang-Heon Jeon <ekffu200098@gmail.com> | 2026-09-27 18:17:54 +0900 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2026-09-29 16:52:45 +0200 |
| commit | ae30792e536c80aed87fb11ec9140e55ed99da09 (patch) | |
| tree | 6ec8f4ddaced93ab03a673d02b786b32d9109531 /kernel | |
| parent | 267f1127c0f4035448acc6f2c3321eb38e54eecc (diff) | |
| download | linux-ae30792e536c80aed87fb11ec9140e55ed99da09.tar.gz linux-ae30792e536c80aed87fb11ec9140e55ed99da09.zip | |
printk: increase the ring buffer for more than 16 CPUs by default
The default LOG_BUF_SHIFT is 17, which means 128 KB, and
LOG_CPU_MAX_BUF_SHIFT is 12, which means 4 KB per CPU.
By default the ring buffer is increased when
(num_possible_cpus() - 1) * 4 KB > 64 KB, which requires more than 17
CPUs.
Remove the explicit subtraction of one, so the ring buffer is increased
for more than 16 CPUs, which is a power of two. Also fix the outdated
comment.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20260927091756.50831-1-ekffu200098@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/printk/printk.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index a3c4ee6d9f1d..45c3cfc28e78 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1085,9 +1085,9 @@ static void __init log_buf_add_cpu(void) if (num_possible_cpus() == 1) return; - cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; + cpu_extra = num_possible_cpus() * __LOG_CPU_MAX_BUF_LEN; - /* by default this will only continue through for large > 64 CPUs */ + /* by default this will only continue through for more than 16 CPUs */ if (cpu_extra <= __LOG_BUF_LEN / 2) return; |