On Thu, 2017-03-02 at 17:38 +0100, Arnd Bergmann wrote:
The internal logging infrastructure in ocfs2 causes special warning code to be used with KASAN, which produces rather large stack frames:
fs/ocfs2/super.c: In function 'ocfs2_fill_super': fs/ocfs2/super.c:1219:1: error: the frame size of 3264 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
At least by default it doesn't seem to.
gcc 6.2 allyesconfig, CONFIG_KASAN=y with either CONFIG_KASAN_INLINE or CONFIG_KASAN_OUTLINE
gcc doesn't emit a stack warning
By simply passing the mask by value instead of reference, we can avoid the problem completely.
Any idea why that's so?
On 64-bit architectures, this is also more efficient,
Efficient true, but the same overall stack no?
while on the less common (at least among ocfs2 users) 32-bit architectures, I'm guessing that the resulting code is comparable to what it was before.
The current version was introduced by Joe Perches as an optimization, maybe he can see if my change regresses compared to his.
I don't see it.
Cc: Joe Perches joe@perches.com Fixes: 7c2bd2f930ae ("ocfs2: reduce object size of mlog uses") Signed-off-by: Arnd Bergmann arnd@arndb.de
fs/ocfs2/cluster/masklog.c | 10 +++++----- fs/o cfs2/cluster/masklog.h | 4 ++-- 2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c index d331c2386b94..9720c5443e4d 100644 --- a/fs/ocfs2/cluster/masklog.c +++ b/fs/ocfs2/cluster/masklog.c @@ -64,7 +64,7 @@ static ssize_t mlog_mask_store(u64 mask, const char *buf, size_t count) return count; } -void __mlog_printk(const u64 *mask, const char *func, int line, +void __mlog_printk(const u64 mask, const char *func, int line, const char *fmt, ...) { struct va_format vaf; @@ -72,14 +72,14 @@ void __mlog_printk(const u64 *mask, const char *func, int line, const char *level; const char *prefix = "";
- if (!__mlog_test_u64(*mask, mlog_and_bits) ||
__mlog_test_u64(*mask, mlog_not_bits))
- if (!__mlog_test_u64(mask, mlog_and_bits) ||
__mlog_test_u64(mask, mlog_not_bits))
- if (*mask & ML_ERROR) {
- if (mask & ML_ERROR) { level = KERN_ERR; prefix = "ERROR: ";
- } else if (*mask & ML_NOTICE) {
- } else if (mask & ML_NOTICE) { level = KERN_NOTICE; } else { level = KERN_INFO;
diff --git a/fs/ocfs2/cluster/masklog.h b/fs/ocfs2/cluster/masklog.h index 308ea0eb35fd..0d0f4bf2c3d8 100644 --- a/fs/ocfs2/cluster/masklog.h +++ b/fs/ocfs2/cluster/masklog.h @@ -163,7 +163,7 @@ extern struct mlog_bits mlog_and_bits, mlog_not_bits; #endif __printf(4, 5) -void __mlog_printk(const u64 *m, const char *func, int line, +void __mlog_printk(const u64 m, const char *func, int line, const char *fmt, ...); /* @@ -174,7 +174,7 @@ void __mlog_printk(const u64 *m, const char *func, int line, do { \ u64 _m = MLOG_MASK_PREFIX | (mask); \ if (_m & ML_ALLOWED_BITS) \
__mlog_printk(&_m, __func__, __LINE__, fmt, \
__mlog_printk(_m, __func__, __LINE__, fmt, \ ##__VA_ARGS__); \} while (0)