From d7ec4bfed6c97405c6417970ba06c439e08ab8e3 Mon Sep 17 00:00:00 2001 From: Vaibhav Nagarnaik Date: Tue, 7 Jun 2011 17:01:42 -0700 Subject: ring-buffer: Set __GFP_NORETRY flag for ring buffer allocating process The tracing ring buffer is allocated from kernel memory. While allocating a large chunk of memory, OOM might happen which destabilizes the system. Thus random processes might get killed during the allocation. This patch adds __GFP_NORETRY flag to the ring buffer allocation calls to make it fail more gracefully if the system will not be able to complete the allocation request. Acked-by: David Rientjes Signed-off-by: Vaibhav Nagarnaik Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Michael Rubin Cc: David Sharp Link: http://lkml.kernel.org/r/1307491302-9236-1-git-send-email-vnagarnaik@google.com Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) (limited to 'kernel/trace') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index f00ede314eb6..731201bf4acc 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1004,9 +1004,14 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, for (i = 0; i < nr_pages; i++) { struct page *page; - + /* + * __GFP_NORETRY flag makes sure that the allocation fails + * gracefully without invoking oom-killer and the system is + * not destabilized. + */ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), - GFP_KERNEL, cpu_to_node(cpu_buffer->cpu)); + GFP_KERNEL | __GFP_NORETRY, + cpu_to_node(cpu_buffer->cpu)); if (!bpage) goto free_pages; @@ -1015,7 +1020,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, list_add(&bpage->list, &pages); page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), - GFP_KERNEL, 0); + GFP_KERNEL | __GFP_NORETRY, 0); if (!page) goto free_pages; bpage->page = page_address(page); @@ -1377,13 +1382,20 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size) for_each_buffer_cpu(buffer, cpu) { for (i = 0; i < new_pages; i++) { struct page *page; + /* + * __GFP_NORETRY flag makes sure that the allocation + * fails gracefully without invoking oom-killer and + * the system is not destabilized. + */ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), - GFP_KERNEL, cpu_to_node(cpu)); + GFP_KERNEL | __GFP_NORETRY, + cpu_to_node(cpu)); if (!bpage) goto free_pages; list_add(&bpage->list, &pages); - page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0); + page = alloc_pages_node(cpu_to_node(cpu), + GFP_KERNEL | __GFP_NORETRY, 0); if (!page) goto free_pages; bpage->page = page_address(page); @@ -3737,7 +3749,8 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu) struct buffer_data_page *bpage; struct page *page; - page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, 0); + page = alloc_pages_node(cpu_to_node(cpu), + GFP_KERNEL | __GFP_NORETRY, 0); if (!page) return NULL; -- cgit v1.2.3