From: Vaibhav Nagarnaik Date: Tue, 14 Jun 2011 00:51:57 +0000 (-0700) Subject: tracing: Add a proc file to stop tracing and free buffer X-Git-Tag: v3.1-rc1~299^2~13^2~13 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4f271a2a60c748599b30bb4dafff30d770439b96;p=pandora-kernel.git tracing: Add a proc file to stop tracing and free buffer The proc file entry buffer_size_kb is used to set the size of tracing buffer. The memory to expand the buffer size is kernel memory. Consider a use case where tracing is handled by a user space utility, which acts as a gate keeper for tracing requests. In an OOM condition, tracing is considered a low priority task and if the utility gets killed the ring buffer memory cannot be released back to the kernel. This patch adds a proc file called "free_buffer" whose purpose is to stop tracing and free up the ring buffer when it is closed. The user space process can then set the desired size in buffer_size_kb file and open the fd to the "free_buffer" file. Under OOM condition, if the process gets killed, the kernel closes the file descriptor. The release handler stops the tracing and releases the kernel memory automatically. Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Michael Rubin Cc: David Sharp Signed-off-by: Vaibhav Nagarnaik Link: http://lkml.kernel.org/r/1308012717-11148-1-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt --- Reading git-diff-tree failed