Messages in this thread Patch in this message | | | Date | Thu, 02 Apr 2009 15:16:59 +0800 | From | Lai Jiangshan <> | Subject | [PATCH 2/4] tracing: allocate page when need |
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Impact: Cleanup
Sometimes, we open trace_pipe_raw, but we don't read(2) it, we just splice(2) it, thus, the page is not used.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7283b99..20e9f33 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3257,19 +3257,13 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp) info->tr = &global_trace; info->cpu = cpu; - info->spare = ring_buffer_alloc_read_page(info->tr->buffer); + info->spare = NULL; /* Force reading ring buffer for first read */ info->read = (unsigned int)-1; - if (!info->spare) - goto out; filp->private_data = info; return nonseekable_open(inode, filp); - - out: - kfree(info); - return -ENOMEM; } static ssize_t @@ -3284,6 +3278,11 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, if (!count) return 0; + if (!info->spare) + info->spare = ring_buffer_alloc_read_page(info->tr->buffer); + if (!info->spare) + return -ENOMEM; + /* Do we have previous read data to read? */ if (info->read < PAGE_SIZE) goto read; @@ -3322,7 +3321,8 @@ static int tracing_buffers_release(struct inode *inode, struct file *file) { struct ftrace_buffer_info *info = file->private_data; - ring_buffer_free_read_page(info->tr->buffer, info->spare); + if (info->spare) + ring_buffer_free_read_page(info->tr->buffer, info->spare); kfree(info); return 0;
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