[v2] libibverbs: ibv_fork_init() and libhugetlbfs

Commit Message

Alexander Schmidt May 31, 2010, 9:13 a.m. UTC

None

Patch

--- libibverbs-1.1.2.orig/src/memory.c
+++ libibverbs-1.1.2/src/memory.c
@@ -40,6 +40,10 @@ 
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include <limits.h>
 
 #include "ibverbs.h"
 
@@ -68,12 +72,117 @@  struct ibv_mem_node {
 static struct ibv_mem_node *mm_root;
 static pthread_mutex_t mm_mutex = PTHREAD_MUTEX_INITIALIZER;
 static int page_size;
+static int huge_page_enabled;
 static int too_late;
 
+static int is_huge_page_enabled(void)
+{
+	int n, ret = 0;
+	char *bufp;
+	DIR *dir;
+	struct dirent *entry;
+	FILE *file;
+	unsigned long nr_hugepages;
+	char buf[1024];
+
+	dir = opendir("/sys/kernel/mm/hugepages/");
+	if (!dir)
+		return 0;
+
+	while ((entry = readdir(dir))) {
+		if (strncmp(entry->d_name, "hugepages-", 10))
+			continue;
+
+		snprintf(buf, sizeof(buf), "/sys/kernel/mm/hugepages/%s/nr_hugepages",
+				entry->d_name);
+
+		file = fopen(buf, "r");
+		if (!file)
+			continue;
+
+		bufp = fgets(buf, sizeof(buf), file);
+		fclose(file);
+		if (!bufp)
+			continue;
+
+		n = sscanf(buf, "%lu", &nr_hugepages);
+		if (n < 1)
+			continue;
+
+		if (nr_hugepages) {
+			ret = 1;
+			goto out;
+		}
+	}
+
+out:
+	closedir(dir);
+
+	return ret;
+}
+
+static unsigned long smaps_page_size(FILE *file)
+{
+	int n;
+	unsigned long size = page_size;
+	char buf[1024];
+
+	while (fgets(buf, sizeof(buf), file) != NULL) {
+		if (!strstr(buf, "KernelPageSize:"))
+			continue;
+
+		n = sscanf(buf, "%*s %lu", &size);
+		if (n < 1)
+			continue;
+
+		/* page size is printed in Kb */
+		size = size * 1024;
+
+		break;
+	}
+
+	return size;
+}
+
+static unsigned long get_page_size(void *base)
+{
+	unsigned long ret = page_size;
+	pid_t pid;
+	FILE *file;
+	char buf[1024];
+
+	pid = getpid();
+	snprintf(buf, sizeof(buf), "/proc/%d/smaps", pid);
+
+	file = fopen(buf, "r");
+	if (!file)
+		goto out;
+
+	while (fgets(buf, sizeof(buf), file) != NULL) {
+		int n;
+		uintptr_t range_start, range_end;
+
+		n = sscanf(buf, "%lx-%lx", &range_start, &range_end);
+
+		if (n < 2)
+			continue;
+
+		if ((uintptr_t) base >= range_start && (uintptr_t) base < range_end) {
+			ret = smaps_page_size(file);
+			break;
+		}
+	}
+	fclose(file);
+
+out:
+	return ret;
+}
+
 int ibv_fork_init(void)
 {
-	void *tmp;
+	void *tmp, *tmp_aligned;
 	int ret;
+	unsigned long size;
 
 	if (mm_root)
 		return 0;
@@ -88,8 +197,18 @@  int ibv_fork_init(void)
 	if (posix_memalign(&tmp, page_size, page_size))
 		return ENOMEM;
 
-	ret = madvise(tmp, page_size, MADV_DONTFORK) ||
-	      madvise(tmp, page_size, MADV_DOFORK);
+	huge_page_enabled = is_huge_page_enabled();
+
+	if (huge_page_enabled) {
+		size = get_page_size(tmp);
+		tmp_aligned = (void *)((uintptr_t)tmp & ~(size - 1));
+	} else {
+		size = page_size;
+		tmp_aligned = tmp;
+	}
+
+	ret = madvise(tmp_aligned, size, MADV_DONTFORK) ||
+	      madvise(tmp_aligned, size, MADV_DOFORK);
 
 	free(tmp);
 
@@ -452,15 +571,21 @@  static int ibv_madvise_range(void *base,
 	struct ibv_mem_node *node, *tmp;
 	int inc;
 	int ret = 0;
+	unsigned long range_page_size;
 
 	if (!size)
 		return 0;
 
 	inc = advice == MADV_DONTFORK ? 1 : -1;
 
-	start = (uintptr_t) base & ~(page_size - 1);
-	end   = ((uintptr_t) (base + size + page_size - 1) &
-		 ~(page_size - 1)) - 1;
+	if (huge_page_enabled)
+		range_page_size = get_page_size(base);
+	else
+		range_page_size = page_size;
+
+	start = (uintptr_t) base & ~(range_page_size - 1);
+	end   = ((uintptr_t) (base + size + range_page_size - 1) &
+		 ~(range_page_size - 1)) - 1;
 
 	pthread_mutex_lock(&mm_mutex);