Add kmalloc failover to vmalloc

[lttng-modules.git] / wrapper / vmalloc.h

diff --git a/wrapper/vmalloc.h b/wrapper/vmalloc.h
index 2332439fe34c56515cefcaa4eda787a65ecaf835..2dd06cbf53e0fe565538b99fd633be504f7b7f9f 100644 (file)
--- a/wrapper/vmalloc.h
+++ b/wrapper/vmalloc.h
@@ -25,6 +25,9 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <linux/version.h>
+#include <linux/vmalloc.h>
+
 #ifdef CONFIG_KALLSYMS
 
 #include <linux/kallsyms.h>
@@ -51,8 +54,6 @@ void wrapper_vmalloc_sync_all(void)
 }
 #else
 
-#include <linux/vmalloc.h>
-
 static inline
 void wrapper_vmalloc_sync_all(void)
 {
@@ -60,4 +61,168 @@ void wrapper_vmalloc_sync_all(void)
 }
 #endif
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,12,0))
+static inline
+void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
+{
+       void *ret;
+
+       ret = kvmalloc_node(size, flags, node);
+       if (is_vmalloc_addr(ret)) {
+               /*
+                * Make sure we don't trigger recursive page faults in the
+                * tracing fast path.
+                */
+               wrapper_vmalloc_sync_all();
+       }
+       return ret;
+}
+
+static inline
+void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
+{
+       return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
+}
+
+static inline
+void *lttng_kvmalloc(unsigned long size, gfp_t flags)
+{
+       return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
+}
+
+static inline
+void *lttng_kvzalloc(unsigned long size, gfp_t flags)
+{
+       return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
+}
+
+static inline
+void lttng_kvfree(const void *addr)
+{
+       kvfree(addr);
+}
+
+#else
+
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+/*
+ * kallsyms wrapper of __vmalloc_node with a fallback to kmalloc_node.
+ */
+static inline
+void *__lttng_vmalloc_node_fallback(unsigned long size, unsigned long align,
+                         gfp_t gfp_mask, pgprot_t prot, int node, void *caller)
+{
+       void *ret;
+
+#ifdef CONFIG_KALLSYMS
+       /*
+        * If we have KALLSYMS, get * __vmalloc_node which is not exported.
+        */
+       void *(*lttng__vmalloc_node)(unsigned long size, unsigned long align,
+                       gfp_t gfp_mask, pgprot_t prot, int node, void *caller);
+
+       lttng__vmalloc_node = (void *) kallsyms_lookup_funcptr("__vmalloc_node");
+       ret = lttng__vmalloc_node(size, align, gfp_mask, prot, node, caller);
+#else
+       /*
+        * If we don't have KALLSYMS, fallback to kmalloc_node.
+        */
+       ret = kmalloc_node(size, flags, node);
+#endif
+
+       return ret;
+}
+
+/**
+ * lttng_kvmalloc_node - attempt to allocate physically contiguous memory, but upon
+ * failure, fall back to non-contiguous (vmalloc) allocation.
+ * @size: size of the request.
+ * @flags: gfp mask for the allocation - must be compatible with GFP_KERNEL.
+ *
+ * Uses kmalloc to get the memory but if the allocation fails then falls back
+ * to the vmalloc allocator. Use lttng_kvfree to free the memory.
+ *
+ * Reclaim modifiers - __GFP_NORETRY, __GFP_REPEAT and __GFP_NOFAIL are not supported
+ */
+static inline
+void *lttng_kvmalloc_node(unsigned long size, gfp_t flags, int node)
+{
+       void *ret;
+
+       /*
+        * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables)
+        * so the given set of flags has to be compatible.
+        */
+       WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL);
+
+       /*
+        * If the allocation fits in a single page, do not fallback.
+        */
+       if (size <= PAGE_SIZE) {
+               return kmalloc_node(size, flags, node);
+       }
+
+       /*
+        * Make sure that larger requests are not too disruptive - no OOM
+        * killer and no allocation failure warnings as we have a fallback
+        */
+       ret = kmalloc_node(size, flags | __GFP_NOWARN | __GFP_NORETRY, node);
+       if (!ret) {
+               if (node == NUMA_NO_NODE) {
+                       /*
+                        * If no node was specified, use __vmalloc which is
+                        * always exported.
+                        */
+                       ret = __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL);
+               } else {
+                       /*
+                        * Otherwise, we need to select a node but __vmalloc_node
+                        * is not exported, use this fallback wrapper which uses
+                        * kallsyms if available or falls back to kmalloc_node.
+                        */
+                       ret = __lttng_vmalloc_node_fallback(size, 1,
+                                       flags | __GFP_HIGHMEM, PAGE_KERNEL, node,
+                                       __builtin_return_address(0));
+               }
+
+               /*
+                * Make sure we don't trigger recursive page faults in the
+                * tracing fast path.
+                */
+               wrapper_vmalloc_sync_all();
+       }
+       return ret;
+}
+
+static inline
+void *lttng_kvzalloc_node(unsigned long size, gfp_t flags, int node)
+{
+       return lttng_kvmalloc_node(size, flags | __GFP_ZERO, node);
+}
+
+static inline
+void *lttng_kvmalloc(unsigned long size, gfp_t flags)
+{
+       return lttng_kvmalloc_node(size, flags, NUMA_NO_NODE);
+}
+
+static inline
+void *lttng_kvzalloc(unsigned long size, gfp_t flags)
+{
+       return lttng_kvzalloc_node(size, flags, NUMA_NO_NODE);
+}
+
+static inline
+void lttng_kvfree(const void *addr)
+{
+       if (is_vmalloc_addr(addr)) {
+               vfree(addr);
+       } else {
+               kfree(addr);
+       }
+}
+#endif
+
 #endif /* _LTTNG_WRAPPER_VMALLOC_H */