Add a puts function for the coredump printer to bypass printf() for constant strings for a speed boost. Reorganize the coredump printf callback to share as much code as possible.
v2: Try to reuse code between print and puts as suggested by Chris Wilson
Signed-off-by: Jordan Crouse jcrouse@codeaurora.org --- drivers/gpu/drm/drm_print.c | 84 +++++++++++++++++++++---------------- include/drm/drm_print.h | 2 + 2 files changed, 51 insertions(+), 35 deletions(-)
diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index 8ddeaba4bf9d..7631a40389ba 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -30,7 +30,7 @@ #include <drm/drmP.h> #include <drm/drm_print.h>
-void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf) +void __drm_puts_coredump(struct drm_printer *p, const char *str) { struct drm_print_iterator *iterator = p->arg; ssize_t len; @@ -38,26 +38,16 @@ void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf) if (!iterator->remain) return;
- /* Figure out how big the string will be */ - len = snprintf(NULL, 0, "%pV", vaf); - if (iterator->offset < iterator->start) { - char *buf; ssize_t copy;
+ len = strlen(str); + if (iterator->offset + len <= iterator->start) { iterator->offset += len; return; }
- /* Print the string into a temporary buffer */ - buf = kmalloc(len + 1, - GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY); - if (!buf) - return; - - snprintf(buf, len + 1, "%pV", vaf); - copy = len - (iterator->start - iterator->offset);
if (copy > iterator->remain) @@ -65,42 +55,66 @@ void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf)
/* Copy out the bit of the string that we need */ memcpy(iterator->data, - buf + (iterator->start - iterator->offset), copy); + str + (iterator->start - iterator->offset), copy);
iterator->offset = iterator->start + copy; iterator->remain -= copy; - - kfree(buf); } else { - char *buf; ssize_t pos = iterator->offset - iterator->start;
- if (len < iterator->remain) { - snprintf(((char *) iterator->data) + pos, - iterator->remain, "%pV", vaf); + len = min_t(ssize_t, strlen(str), iterator->remain);
- iterator->offset += len; - iterator->remain -= len; + memcpy(iterator->data + pos, str, len);
- return; - } + iterator->offset += len; + iterator->remain -= len; + } +} +EXPORT_SYMBOL(__drm_puts_coredump);
- /* Print the string into a temporary buffer */ - buf = kmalloc(len + 1, - GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY); - if (!buf) - return; +void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf) +{ + struct drm_print_iterator *iterator = p->arg; + size_t len; + char *buf; + + if (!iterator->remain) + return; + + /* Figure out how big the string will be */ + len = snprintf(NULL, 0, "%pV", vaf); + + /* This is the easiest path, we've already advanced beyond the offset */ + if (iterator->offset + len <= iterator->start) { + iterator->offset += len; + return; + }
- snprintf(buf, len + 1, "%pV", vaf); + /* Then check if we can directly copy into the target buffer */ + if ((iterator->offset >= iterator->start) && (len < iterator->remain)) { + ssize_t pos = iterator->offset - iterator->start;
- /* Copy out the remaining bits */ - memcpy(iterator->data + pos, buf, iterator->remain); + snprintf(((char *) iterator->data) + pos, + iterator->remain, "%pV", vaf);
- iterator->offset += iterator->remain; - iterator->remain = 0; + iterator->offset += len; + iterator->remain -= len;
- kfree(buf); + return; } + + /* + * Finally, hit the slow path and make a temporary string to copy over + * using _drm_puts_coredump + */ + buf = kmalloc(len + 1, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY); + if (!buf) + return; + + snprintf(buf, len + 1, "%pV", vaf); + __drm_puts_coredump(p, (const char *) buf); + + kfree(buf); } EXPORT_SYMBOL(__drm_printfn_coredump);
diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h index 1834ec6244bf..e0e791a094b9 100644 --- a/include/drm/drm_print.h +++ b/include/drm/drm_print.h @@ -75,6 +75,7 @@ struct drm_printer { };
void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf); +void __drm_puts_coredump(struct drm_printer *p, const char *str); void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf); void __drm_puts_seq_file(struct drm_printer *p, const char *str); void __drm_printfn_info(struct drm_printer *p, struct va_format *vaf); @@ -163,6 +164,7 @@ drm_coredump_printer(struct drm_print_iterator *iter) { struct drm_printer p = { .printfn = __drm_printfn_coredump, + .puts = __drm_puts_coredump, .arg = iter, };