Messages in this thread Patch in this message | | | Date | Sat, 28 Nov 2009 16:40:16 +0800 | From | Lai Jiangshan <> | Subject | [PATCH] trace_output: change struct trace_seq's size to PAGE_SIZE |
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It's not very good that we allocate pages with page_order > 1. So we change struct trace_seq's size to PAGE_SIZE.
Where we allocate a struct trace_seq:
kernel/trace/trace.c:3720: s = kmalloc(sizeof(*s), GFP_KERNEL); kernel/trace/trace_events.c:539: s = kmalloc(sizeof(*s), GFP_KERNEL); kernel/trace/trace_events.c:580: s = kmalloc(sizeof(*s), GFP_KERNEL); kernel/trace/trace_events.c:604: s = kmalloc(sizeof(*s), GFP_KERNEL); kernel/trace/trace_events.c:660: s = kmalloc(sizeof(*s), GFP_KERNEL); kernel/trace/trace_events.c:715: s = kmalloc(sizeof(*s), GFP_KERNEL); kernel/trace/trace_ksym.c:230: s = kmalloc(sizeof(*s), GFP_KERNEL);
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 09077f6..128d86a 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -7,13 +7,24 @@ /* * Trace sequences are used to allow a function to call several other functions - * to create a string of data to use (up to a max of PAGE_SIZE). + * to create a string of data to use (up to a max of TRACE_SEQ_BUFFER_SIZE). */ struct trace_seq { - unsigned char buffer[PAGE_SIZE]; - unsigned int len; - unsigned int readpos; + union { + struct { + unsigned int len; + unsigned int readpos; + unsigned char buffer[]; + }; + unsigned char __make_it_PAGE_SIZE[PAGE_SIZE]; + }; +}; + +#define TRACE_SEQ_BUFFER_SIZE (PAGE_SIZE - offsetof(struct trace_seq, buffer)) + +struct __check_trace_seq_size { + int __check[-!!(sizeof(struct trace_seq) - PAGE_SIZE)]; }; static inline void diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index b6c12c6..578e347 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -25,7 +25,10 @@ static int next_event_type = __TRACE_LAST_TYPE + 1; void trace_print_seq(struct seq_file *m, struct trace_seq *s) { - int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; + int len = s->len; + + if (len >= TRACE_SEQ_BUFFER_SIZE) + len = TRACE_SEQ_BUFFER_SIZE - 1; seq_write(m, s->buffer, len); @@ -81,7 +84,7 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter) int trace_seq_printf(struct trace_seq *s, const char *fmt, ...) { - int len = (PAGE_SIZE - 1) - s->len; + int len = (TRACE_SEQ_BUFFER_SIZE - 1) - s->len; va_list ap; int ret; @@ -116,7 +119,7 @@ EXPORT_SYMBOL_GPL(trace_seq_printf); int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) { - int len = (PAGE_SIZE - 1) - s->len; + int len = (TRACE_SEQ_BUFFER_SIZE - 1) - s->len; int ret; if (!len) @@ -136,7 +139,7 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf); int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) { - int len = (PAGE_SIZE - 1) - s->len; + int len = (TRACE_SEQ_BUFFER_SIZE - 1) - s->len; int ret; if (!len) @@ -167,7 +170,7 @@ int trace_seq_puts(struct trace_seq *s, const char *str) { int len = strlen(str); - if (len > ((PAGE_SIZE - 1) - s->len)) + if (len > ((TRACE_SEQ_BUFFER_SIZE - 1) - s->len)) return 0; memcpy(s->buffer + s->len, str, len); @@ -178,7 +181,7 @@ int trace_seq_puts(struct trace_seq *s, const char *str) int trace_seq_putc(struct trace_seq *s, unsigned char c) { - if (s->len >= (PAGE_SIZE - 1)) + if (s->len >= (TRACE_SEQ_BUFFER_SIZE - 1)) return 0; s->buffer[s->len++] = c; @@ -188,7 +191,7 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c) int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) { - if (len > ((PAGE_SIZE - 1) - s->len)) + if (len > ((TRACE_SEQ_BUFFER_SIZE - 1) - s->len)) return 0; memcpy(s->buffer + s->len, mem, len); @@ -220,7 +223,7 @@ void *trace_seq_reserve(struct trace_seq *s, size_t len) { void *ret; - if (len > ((PAGE_SIZE - 1) - s->len)) + if (len > ((TRACE_SEQ_BUFFER_SIZE - 1) - s->len)) return NULL; ret = s->buffer + s->len; @@ -233,9 +236,9 @@ int trace_seq_path(struct trace_seq *s, struct path *path) { unsigned char *p; - if (s->len >= (PAGE_SIZE - 1)) + if (s->len >= (TRACE_SEQ_BUFFER_SIZE - 1)) return 0; - p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); + p = d_path(path, s->buffer + s->len, TRACE_SEQ_BUFFER_SIZE - s->len); if (!IS_ERR(p)) { p = mangle_path(s->buffer + s->len, p, "\n"); if (p) {
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