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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2024-02-28 15:00:03 +0100 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2024-03-19 16:11:42 +0100 |
| commit | c26ec799042a3888935d59b599f33e41efedf5f8 (patch) | |
| tree | 7ee6a4051771bdab3fce868f45c5555c0fd0de4b /include/linux/dev_printk.h | |
| parent | 8522f6b760ca588928eede740d5d69dd1e936b49 (diff) | |
| download | lwn-c26ec799042a3888935d59b599f33e41efedf5f8.tar.gz lwn-c26ec799042a3888935d59b599f33e41efedf5f8.zip | |
dev_printk: Add and use dev_no_printk()
When printk-indexing is enabled, each dev_printk() invocation emits a
pi_entry structure. This is even true when the dev_printk() is
protected by an always-false check, as is typically the case for debug
messages: while the actual code to print the message is optimized out by
the compiler, the pi_entry structure is still emitted.
Avoid emitting pi_entry structures for unavailable dev_printk() kernel
messages by:
1. Introducing a dev_no_printk() helper, mimicked after the existing
no_printk() helper, which calls _dev_printk() instead of
dev_printk(),
2. Replacing all "if (0) dev_printk(...)" constructs by calls to the
new helper.
This reduces the size of an arm64 defconfig kernel with
CONFIG_PRINTK_INDEX=y by 957 KiB.
Fixes: ad7d61f159db7397 ("printk: index: Add indexing support to dev_printk")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/8583d54f1687c801c6cda8edddf2cf0344c6e883.1709127473.git.geert+renesas@glider.be
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'include/linux/dev_printk.h')
| -rw-r--r-- | include/linux/dev_printk.h | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h index 6bfe70decc9f..ae80a303c216 100644 --- a/include/linux/dev_printk.h +++ b/include/linux/dev_printk.h @@ -130,6 +130,16 @@ void _dev_info(const struct device *dev, const char *fmt, ...) }) /* + * Dummy dev_printk for disabled debugging statements to use whilst maintaining + * gcc's format checking. + */ +#define dev_no_printk(level, dev, fmt, ...) \ + ({ \ + if (0) \ + _dev_printk(level, dev, fmt, ##__VA_ARGS__); \ + }) + +/* * #defines for all the dev_<level> macros to prefix with whatever * possible use of #define dev_fmt(fmt) ... */ @@ -158,10 +168,7 @@ void _dev_info(const struct device *dev, const char *fmt, ...) dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #else #define dev_dbg(dev, fmt, ...) \ -({ \ - if (0) \ - dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \ -}) + dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #endif #ifdef CONFIG_PRINTK @@ -247,20 +254,14 @@ do { \ } while (0) #else #define dev_dbg_ratelimited(dev, fmt, ...) \ -do { \ - if (0) \ - dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \ -} while (0) + dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #endif #ifdef VERBOSE_DEBUG #define dev_vdbg dev_dbg #else #define dev_vdbg(dev, fmt, ...) \ -({ \ - if (0) \ - dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \ -}) + dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #endif /* |