On Fri, 17 Apr 2015 00:17:50 -0700 Joe Perches <j...@perches.com> wrote:
> Using a function for __mlog_printk instead of a macro
> reduces the object size of built-in.o more than 120KB, or
> ~10% overall (x86-64 defconfig with all ocfs2 options)
>
> $ size fs/ocfs2/built-in.o*
> text data bss dec hex filename
> 936255 118071 134408 1188734 12237e fs/ocfs2/built-in.o.new
> 1064081 118071 134408 1316560 1416d0 fs/ocfs2/built-in.o.old
It's a start.
> --- a/fs/ocfs2/cluster/masklog.c
> +++ b/fs/ocfs2/cluster/masklog.c
> @@ -64,6 +64,23 @@ static ssize_t mlog_mask_store(u64 mask, const char *buf,
> size_t count)
> return count;
> }
>
> +void __mlog_printk(const char *level, const char *func, int line,
> + const char *fmt, ...)
> +{
> + struct va_format vaf;
> + va_list args;
> +
> + va_start(args, fmt);
> +
> + vaf.fmt = fmt;
> + vaf.va = &args;
> +
> + printk("%s(%s,%u,%lu):%s:%d %pV",
> + level, current->comm, task_pid_nr(current), __mlog_cpu_guess,
> + func, line, &vaf);
> +
> + va_end(args);
> +}
Logging function-name and line-number was a bit weird. I wonder if
anyone will mind if this is converted to file-n-line, as God intended.
That will shrink rodata a bit, because number-of-files is a lot less
than number-of-functions.
> struct mlog_attribute {
> struct attribute attr;
> u64 mask;
> diff --git a/fs/ocfs2/cluster/masklog.h b/fs/ocfs2/cluster/masklog.h
> index 7fdc25a..6036e6a 100644
> --- a/fs/ocfs2/cluster/masklog.h
> +++ b/fs/ocfs2/cluster/masklog.h
> @@ -168,7 +168,8 @@ extern struct mlog_bits mlog_and_bits, mlog_not_bits;
> * scream. just do this instead of trying to guess which we're building
> * against.. *sigh*.
> */
> -#define __mlog_cpu_guess ({ \
> +#define __mlog_cpu_guess \
> +({ \
While we're in there we should turn this into __mlog_cpu_guess().
Or, preferably, just zap the sorry thing and use
raw_smp_processor_id().
> unsigned long _cpu = get_cpu(); \
> put_cpu(); \
> _cpu; \
> @@ -178,21 +179,25 @@ extern struct mlog_bits mlog_and_bits, mlog_not_bits;
> * before ##args is intentional. Otherwise, gcc 2.95 will eat the
> * previous token if args expands to nothing.
> */
> -#define __mlog_printk(level, fmt, args...) \
> - printk(level "(%s,%u,%lu):%s:%d " fmt, current->comm, \
> - task_pid_nr(current), __mlog_cpu_guess, \
> - __PRETTY_FUNCTION__, __LINE__ , ##args)
> +__printf(4, 5)
> +void __mlog_printk(const char *level, const char *func, int line,
> + const char *fmt, ...);
>
> -#define mlog(mask, fmt, args...) do {
> \
> +#define mlog(mask, fmt, ...) \
> +do { \
> u64 __m = MLOG_MASK_PREFIX | (mask); \
> if ((__m & ML_ALLOWED_BITS) && \
> __mlog_test_u64(__m, mlog_and_bits) && \
> !__mlog_test_u64(__m, mlog_not_bits)) { \
> if (__m & ML_ERROR) \
All this goop can also be uninlined?
> - __mlog_printk(KERN_ERR, "ERROR: "fmt , ##args); \
> + __mlog_printk(KERN_ERR, __func__, __LINE__, \
> + "ERROR: " fmt, ##__VA_ARGS__); \
> else if (__m & ML_NOTICE) \
> - __mlog_printk(KERN_NOTICE, fmt , ##args); \
> - else __mlog_printk(KERN_INFO, fmt , ##args); \
> + __mlog_printk(KERN_NOTICE, __func__, __LINE__, \
> + fmt, ##__VA_ARGS__); \
> + else \
> + __mlog_printk(KERN_INFO, __func__, __LINE__, \
> + fmt, ##__VA_ARGS__); \
> } \
> } while (0)
>
I guess this patch is a step on the way - a 10% shrink is decent. But
I believe that with full uninlining of the ocfs2 logging code we can
shrink the filesystem's footprint by 50%.
This code needs some pretty serious rework and rethink, perhaps
involving a change to the emitted info. I was hoping one of the ocfs2
developers would take the bait, but they're all in hiding.
If you feel like undertaking such a rotorooting then go wild - that should
wake 'em up ;)
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