From: Ralf Hoffmann <ralf.hoffmann@allegro-packets.com>
Date: Thu, 7 Jan 2016 14:54:02 +0000 (+0100)
Subject: eal/linux: change hugepage sorting to avoid overlapping memcpy
X-Git-Tag: spdx-start~7568
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=a5f6b5ddca9617974321728eb0e2bc6098ad26ff;p=dpdk.git

eal/linux: change hugepage sorting to avoid overlapping memcpy

with only one hugepage or already sorted hugepage addresses, the sort
function called memcpy with same src and dst pointer. Debugging with
valgrind will issue a warning about overlapping area. This patch changes
the sort method to qsort to avoid this behavior. The separate sort
function is no longer necessary.

Suggested-by: Jay Rolette <rolette@infiniteio.com>
Signed-off-by: Ralf Hoffmann <ralf.hoffmann@allegro-packets.com>
Acked-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
---

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 6008533b0d..5b9132c672 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -693,54 +693,23 @@ error:
 	return -1;
 }
 
-/*
- * Sort the hugepg_tbl by physical address (lower addresses first on x86,
- * higher address first on powerpc). We use a slow algorithm, but we won't
- * have millions of pages, and this is only done at init time.
- */
 static int
-sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
+cmp_physaddr(const void *a, const void *b)
 {
-	unsigned i, j;
-	int compare_idx;
-	uint64_t compare_addr;
-	struct hugepage_file tmp;
-
-	for (i = 0; i < hpi->num_pages[0]; i++) {
-		compare_addr = 0;
-		compare_idx = -1;
-
-		/*
-		 * browse all entries starting at 'i', and find the
-		 * entry with the smallest addr
-		 */
-		for (j=i; j< hpi->num_pages[0]; j++) {
-
-			if (compare_addr == 0 ||
-#ifdef RTE_ARCH_PPC_64
-				hugepg_tbl[j].physaddr > compare_addr) {
+#ifndef RTE_ARCH_PPC_64
+	const struct hugepage_file *p1 = (const struct hugepage_file *)a;
+	const struct hugepage_file *p2 = (const struct hugepage_file *)b;
 #else
-				hugepg_tbl[j].physaddr < compare_addr) {
+	/* PowerPC needs memory sorted in reverse order from x86 */
+	const struct hugepage_file *p1 = (const struct hugepage_file *)b;
+	const struct hugepage_file *p2 = (const struct hugepage_file *)a;
 #endif
-				compare_addr = hugepg_tbl[j].physaddr;
-				compare_idx = j;
-			}
-		}
-
-		/* should not happen */
-		if (compare_idx == -1) {
-			RTE_LOG(ERR, EAL, "%s(): error in physaddr sorting\n", __func__);
-			return -1;
-		}
-
-		/* swap the 2 entries in the table */
-		memcpy(&tmp, &hugepg_tbl[compare_idx],
-			sizeof(struct hugepage_file));
-		memcpy(&hugepg_tbl[compare_idx], &hugepg_tbl[i],
-			sizeof(struct hugepage_file));
-		memcpy(&hugepg_tbl[i], &tmp, sizeof(struct hugepage_file));
-	}
-	return 0;
+	if (p1->physaddr < p2->physaddr)
+		return -1;
+	else if (p1->physaddr > p2->physaddr)
+		return 1;
+	else
+		return 0;
 }
 
 /*
@@ -1187,8 +1156,8 @@ rte_eal_hugepage_init(void)
 			goto fail;
 		}
 
-		if (sort_by_physaddr(&tmp_hp[hp_offset], hpi) < 0)
-			goto fail;
+		qsort(&tmp_hp[hp_offset], hpi->num_pages[0],
+		      sizeof(struct hugepage_file), cmp_physaddr);
 
 #ifdef RTE_EAL_SINGLE_FILE_SEGMENTS
 		/* remap all hugepages into single file segments */