[dpdk-stable] patch 'net/virtio-user: fix hugepage files enumeration' has been queued to stable release 18.02.2

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 18.02.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/16/18. So please
shout if anyone has objections.

Thanks.

Luca Boccassi

---
>From becbf25bf99968d3153475ea339008334185fb83 Mon Sep 17 00:00:00 2001
From: Jianfeng Tan <jianfeng.tan at intel.com>
Date: Thu, 26 Apr 2018 15:34:07 +0000
Subject: [PATCH] net/virtio-user: fix hugepage files enumeration

[ upstream commit 169a9da64a859e1782e49886e7214982304a580f ]

After the commit 2a04139f66b4 ("eal: add single file segments option"),
one hugepage file could contain multiple hugepages which are further
mapped to different memory regions.

Original enumeration implementation cannot handle this situation.

This patch filters out the duplicated files; and adjust the size after
the enumeration.

Fixes: 6a84c37e3975 ("net/virtio-user: add vhost-user adapter layer")

Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
Acked-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 .../howto/virtio_user_for_container_networking.rst |  3 ++-
 drivers/net/virtio/virtio_user/vhost_user.c        | 28 ++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/doc/guides/howto/virtio_user_for_container_networking.rst b/doc/guides/howto/virtio_user_for_container_networking.rst
index aa68b5315..476ce3a63 100644
--- a/doc/guides/howto/virtio_user_for_container_networking.rst
+++ b/doc/guides/howto/virtio_user_for_container_networking.rst
@@ -109,7 +109,8 @@ We have below limitations in this solution:
  * Cannot work with --no-huge option. Currently, DPDK uses anonymous mapping
    under this option which cannot be reopened to share with vhost backend.
  * Cannot work when there are more than VHOST_MEMORY_MAX_NREGIONS(8) hugepages.
-   In another word, do not use 2MB hugepage so far.
+   If you have more regions (especially when 2MB hugepages are used), the option,
+   --single-file-segments, can help to reduce the number of shared files.
  * Applications should not use file name like HUGEFILE_FMT ("%smap_%d"). That
    will bring confusion when sharing hugepage files with backend by name.
  * Root privilege is a must. DPDK resolves physical addresses of hugepages
diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c
index 91c6449bb..163bf93ea 100644
--- a/drivers/net/virtio/virtio_user/vhost_user.c
+++ b/drivers/net/virtio/virtio_user/vhost_user.c
@@ -138,12 +138,13 @@ struct hugepage_file_info {
 static int
 get_hugepage_file_info(struct hugepage_file_info huges[], int max)
 {
-	int idx;
+	int idx, k, exist;
 	FILE *f;
 	char buf[BUFSIZ], *tmp, *tail;
 	char *str_underline, *str_start;
 	int huge_index;
 	uint64_t v_start, v_end;
+	struct stat stats;
 
 	f = fopen("/proc/self/maps", "r");
 	if (!f) {
@@ -183,16 +184,39 @@ get_hugepage_file_info(struct hugepage_file_info huges[], int max)
 		if (sscanf(str_start, "map_%d", &huge_index) != 1)
 			continue;
 
+		/* skip duplicated file which is mapped to different regions */
+		for (k = 0, exist = -1; k < idx; ++k) {
+			if (!strcmp(huges[k].path, tmp)) {
+				exist = k;
+				break;
+			}
+		}
+		if (exist >= 0)
+			continue;
+
 		if (idx >= max) {
 			PMD_DRV_LOG(ERR, "Exceed maximum of %d", max);
 			goto error;
 		}
+
 		huges[idx].addr = v_start;
-		huges[idx].size = v_end - v_start;
+		huges[idx].size = v_end - v_start; /* To be corrected later */
 		snprintf(huges[idx].path, PATH_MAX, "%s", tmp);
 		idx++;
 	}
 
+	/* correct the size for files who have many regions */
+	for (k = 0; k < idx; ++k) {
+		if (stat(huges[k].path, &stats) < 0) {
+			PMD_DRV_LOG(ERR, "Failed to stat %s, %s\n",
+				    huges[k].path, strerror(errno));
+			continue;
+		}
+		huges[k].size = stats.st_size;
+		PMD_DRV_LOG(INFO, "file %s, size %zx\n",
+			    huges[k].path, huges[k].size);
+	}
+
 	fclose(f);
 	return idx;
 
-- 
2.14.2