X-Git-Url: http://git.lttng.org/?p=lttng-modules.git;a=blobdiff_plain;f=lib%2Fringbuffer%2Fring_buffer_backend.c;h=8207f764377a34f5cb0fda0e41da8e56985dbd45;hp=9d199e516aacbaf009538faf394671113e18bf70;hb=1f0ab1eb0409d23de5f67cc588c3ea4cee4d10e0;hpb=426eff93d09b3e6709d6e6d29a285ef4bcdf60c6

diff --git a/lib/ringbuffer/ring_buffer_backend.c b/lib/ringbuffer/ring_buffer_backend.c
index 9d199e51..8207f764 100644
--- a/lib/ringbuffer/ring_buffer_backend.c
+++ b/lib/ringbuffer/ring_buffer_backend.c
@@ -12,6 +12,7 @@
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
+#include <linux/oom.h>
 #include <linux/cpu.h>
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
@@ -43,6 +44,23 @@ int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config
 	unsigned long i;
 
 	num_pages = size >> PAGE_SHIFT;
+
+	/*
+	 * Verify that the number of pages requested for that buffer is smaller
+	 * than the number of available pages on the system. si_mem_available()
+	 * returns an _estimate_ of the number of available pages.
+	 */
+	if (num_pages > si_mem_available())
+		goto not_enough_pages;
+
+	/*
+	 * Set the current user thread as the first target of the OOM killer.
+	 * If the estimate received by si_mem_available() was off, and we do
+	 * end up running out of memory because of this buffer allocation, we
+	 * want to kill the offending app first.
+	 */
+	set_current_oom_origin();
+
 	num_pages_per_subbuf = num_pages >> get_count_order(num_subbuf);
 	subbuf_size = chanb->subbuf_size;
 	num_subbuf_alloc = num_subbuf;
@@ -137,6 +155,7 @@ int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config
 	 * will not fault.
 	 */
 	wrapper_vmalloc_sync_all();
+	clear_current_oom_origin();
 	vfree(pages);
 	return 0;
 
@@ -153,6 +172,8 @@ depopulate:
 array_error:
 	vfree(pages);
 pages_error:
+	clear_current_oom_origin();
+not_enough_pages:
 	return -ENOMEM;
 }