support for huge pages

common/nanoBench.c

@@ -45,6 +45,7 @@ void* runtime_rbp;
 void* runtime_rdi;
 void* runtime_rsi;
 void* runtime_rsp;
+void* huge_pages = NULL;
 int64_t pfc_mem[MAX_PROGRAMMABLE_COUNTERS];
 void* RSP_mem;
 
@@ -383,7 +384,11 @@ void create_runtime_code(char* measurement_template, long local_unroll_count, lo
             templateI += 8;
             rci += 8;
         } else if (starts_with_magic_bytes(&measurement_template[templateI], MAGIC_BYTES_RUNTIME_R14)) {
-            *(void**)(&runtime_code[rci]) = runtime_r14 + RUNTIME_R_SIZE/2;
+            if (huge_pages) {
+                *(void**)(&runtime_code[rci]) = huge_pages;
+            } else {
+                *(void**)(&runtime_code[rci]) = runtime_r14 + RUNTIME_R_SIZE/2;
+            }
             templateI += 8;
             rci += 8;
         } else if (starts_with_magic_bytes(&measurement_template[templateI], MAGIC_BYTES_RUNTIME_RBP)) {

common/nanoBench.h

@@ -158,6 +158,9 @@ extern void* runtime_rdi;
 extern void* runtime_rsi;
 extern void* runtime_rsp;
 
+// If non-null, R14 will contain this address instead of runtime_r14.
+extern void* huge_pages;
+
 // Stores performance counter values during measurements.
 extern int64_t pfc_mem[MAX_PROGRAMMABLE_COUNTERS];
 

kernel/Makefile

@@ -20,10 +20,12 @@ CFLAGS_nanoBench.o := -DDEBUG
 
 ccflags-y+=-std=gnu99 -Wno-declaration-after-statement
 
-all:
+all: hp
 	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
 
+hp: hp.o
+
 clean:
-	rm -f ../common/*.o ../common/*.ur-safe
+	rm -f hp ../common/*.o ../common/*.ur-safe
 	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
 

kernel/nb_km.c

@@ -11,6 +11,8 @@
 
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
 #include <../arch/x86/include/asm/fpu/api.h>
 
 #include "../common/nanoBench.h"
@@ -18,6 +20,9 @@
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Andreas Abel");
 
+struct page** pages = NULL;
+unsigned long npages = 0;
+
 static ssize_t init_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) {
     memcpy(buf, code_init, code_init_length);
     return code_init_length;
@@ -158,6 +163,42 @@ static ssize_t agg_store(struct kobject *kobj, struct kobj_attribute *attr, cons
 }
 static struct kobj_attribute agg_attribute =__ATTR(agg, 0660, agg_show, agg_store);
 
+static ssize_t use_huge_pages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) {
+    return 0;
+}
+static ssize_t use_huge_pages_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) {
+    if (huge_pages) {
+        vm_unmap_ram(huge_pages, npages);
+    }
+    for (int i=0; i<npages; i++) {
+       put_page(pages[i]);
+    }
+    vfree(pages);
+
+    long len = *(long*)(buf+sizeof(void*));
+    npages = (len+PAGE_SIZE-1)/PAGE_SIZE;
+    if (npages == 0) {
+        pr_debug("Huge pages disabled.");
+        pages = NULL;
+        huge_pages = NULL;
+        return count;
+    }
+
+    pages = vmalloc(npages * sizeof(struct page*));
+
+    down_read(&current->mm->mmap_sem);
+    int res = get_user_pages(*(unsigned long*)(buf), npages, FOLL_WRITE, pages, NULL);
+    if (res) {
+        int nid = page_to_nid(pages[0]);
+        huge_pages = vm_map_ram(pages, npages, nid, PAGE_KERNEL);
+    }
+    up_read(&current->mm->mmap_sem);
+
+    pr_debug("Huge pages enabled. Start address: %px", huge_pages);
+    return count;
+}
+static struct kobj_attribute use_huge_pages_attribute =__ATTR(use_huge_pages, 0660, use_huge_pages_show, use_huge_pages_store);
+
 static ssize_t verbose_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) {
     return sprintf(buf, "%u\n", verbose);
 }
@@ -381,6 +422,7 @@ static int __init nb_init (void) {
     error |= sysfs_create_file(nb_kobject, &agg_attribute.attr);
     error |= sysfs_create_file(nb_kobject, &basic_mode_attribute.attr);
     error |= sysfs_create_file(nb_kobject, &no_mem_attribute.attr);
+    error |= sysfs_create_file(nb_kobject, &use_huge_pages_attribute.attr);
     error |= sysfs_create_file(nb_kobject, &verbose_attribute.attr);
 
     if (error) {
@@ -402,6 +444,14 @@ static void __exit nb_exit (void) {
     vfree(runtime_rsi);
     vfree(runtime_rsp);
 
+    if (huge_pages) {
+        vm_unmap_ram(huge_pages, npages);
+    }
+    for (int i=0; i<npages; i++) {
+       put_page(pages[i]);
+    }
+    vfree(pages);
+
     for (int i=0; i<MAX_PROGRAMMABLE_COUNTERS; i++) {
         kfree(measurement_results[i]);
         kfree(measurement_results_base[i]);