mem: add internal API to get and set segment fd

Enable setting and retrieving segment fd's internally.

For now, retrieving fd's will not be used anywhere until we
get an external API, but it will be useful for things like
virtio, where we wish to share segment fd's.

Setting segment fd's will not be available as a public API
at this time, but internally it is needed for legacy mode,
because we're not allocating our hugepages in memalloc in
legacy mode case, and we still need to store the fd.

Another user of get segment fd API is memseg info dump, to
show which pages use which fd's.

Not supported on FreeBSD.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

lib/librte_eal/bsdapp/eal/eal_memalloc.c

@@ -47,6 +47,18 @@ eal_memalloc_sync_with_primary(void)
 	return -1;
 }
 
+int
+eal_memalloc_get_seg_fd(int list_idx, int seg_idx)
+{
+	return -1;
+}
+
+int
+eal_memalloc_set_seg_fd(int list_idx, int seg_idx, int fd)
+{
+	return -1;
+}
+
 int
 eal_memalloc_init(void)
 {

lib/librte_eal/common/eal_common_memory.c

@@ -294,7 +294,7 @@ dump_memseg(const struct rte_memseg_list *msl, const struct rte_memseg *ms,
 		void *arg)
 {
 	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
-	int msl_idx, ms_idx;
+	int msl_idx, ms_idx, fd;
 	FILE *f = arg;
 
 	msl_idx = msl - mcfg->memsegs;
@@ -305,10 +305,11 @@ dump_memseg(const struct rte_memseg_list *msl, const struct rte_memseg *ms,
 	if (ms_idx < 0)
 		return -1;
 
+	fd = eal_memalloc_get_seg_fd(msl_idx, ms_idx);
 	fprintf(f, "Segment %i-%i: IOVA:0x%"PRIx64", len:%zu, "
 			"virt:%p, socket_id:%"PRId32", "
 			"hugepage_sz:%"PRIu64", nchannel:%"PRIx32", "
-			"nrank:%"PRIx32"\n",
+			"nrank:%"PRIx32" fd:%i\n",
 			msl_idx, ms_idx,
 			ms->iova,
 			ms->len,
@@ -316,7 +317,8 @@ dump_memseg(const struct rte_memseg_list *msl, const struct rte_memseg *ms,
 			ms->socket_id,
 			ms->hugepage_sz,
 			ms->nchannel,
-			ms->nrank);
+			ms->nrank,
+			fd);
 
 	return 0;
 }

lib/librte_eal/common/eal_memalloc.h

@@ -76,6 +76,12 @@ eal_memalloc_mem_alloc_validator_unregister(const char *name, int socket_id);
 int
 eal_memalloc_mem_alloc_validate(int socket_id, size_t new_len);
 
+int
+eal_memalloc_get_seg_fd(int list_idx, int seg_idx);
+
+int
+eal_memalloc_set_seg_fd(int list_idx, int seg_idx, int fd);
+
 int
 eal_memalloc_init(void);
 

lib/librte_eal/linuxapp/eal/eal_memalloc.c

@@ -1334,16 +1334,10 @@ secondary_msl_create_walk(const struct rte_memseg_list *msl,
 }
 
 static int
-fd_list_create_walk(const struct rte_memseg_list *msl,
+alloc_list(int list_idx, int len)
-		void *arg __rte_unused)
 {
-	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
-	unsigned int i, len;
-	int msl_idx;
 	int *data;
-
+	int i;
-	msl_idx = msl - mcfg->memsegs;
-	len = msl->memseg_arr.len;
 
 	/* ensure we have space to store fd per each possible segment */
 	data = malloc(sizeof(int) * len);
@@ -1355,14 +1349,56 @@ fd_list_create_walk(const struct rte_memseg_list *msl,
 	for (i = 0; i < len; i++)
 		data[i] = -1;
 
-	fd_list[msl_idx].fds = data;
+	fd_list[list_idx].fds = data;
-	fd_list[msl_idx].len = len;
+	fd_list[list_idx].len = len;
-	fd_list[msl_idx].count = 0;
+	fd_list[list_idx].count = 0;
-	fd_list[msl_idx].memseg_list_fd = -1;
+	fd_list[list_idx].memseg_list_fd = -1;
 
 	return 0;
 }
 
+static int
+fd_list_create_walk(const struct rte_memseg_list *msl,
+		void *arg __rte_unused)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	unsigned int len;
+	int msl_idx;
+
+	msl_idx = msl - mcfg->memsegs;
+	len = msl->memseg_arr.len;
+
+	return alloc_list(msl_idx, len);
+}
+
+int
+eal_memalloc_set_seg_fd(int list_idx, int seg_idx, int fd)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+
+	/* if list is not allocated, allocate it */
+	if (fd_list[list_idx].len == 0) {
+		int len = mcfg->memsegs[list_idx].memseg_arr.len;
+
+		if (alloc_list(list_idx, len) < 0)
+			return -1;
+	}
+	fd_list[list_idx].fds[seg_idx] = fd;
+
+	return 0;
+}
+
+int
+eal_memalloc_get_seg_fd(int list_idx, int seg_idx)
+{
+	if (internal_config.single_file_segments)
+		return fd_list[list_idx].memseg_list_fd;
+	/* list not initialized */
+	if (fd_list[list_idx].len == 0)
+		return -1;
+	return fd_list[list_idx].fds[seg_idx];
+}
+
 int
 eal_memalloc_init(void)
 {

lib/librte_eal/linuxapp/eal/eal_memory.c

@@ -772,7 +772,10 @@ remap_segment(struct hugepage_file *hugepages, int seg_start, int seg_end)
 
 		rte_fbarray_set_used(arr, ms_idx);
 
-		close(fd);
+		/* store segment fd internally */
+		if (eal_memalloc_set_seg_fd(msl_idx, ms_idx, fd) < 0)
+			RTE_LOG(ERR, EAL, "Could not store segment fd: %s\n",
+				rte_strerror(rte_errno));
 	}
 	RTE_LOG(DEBUG, EAL, "Allocated %" PRIu64 "M on socket %i\n",
 			(seg_len * page_sz) >> 20, socket_id);
@@ -1771,6 +1774,7 @@ getFileSize(int fd)
 static int
 eal_legacy_hugepage_attach(void)
 {
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
 	struct hugepage_file *hp = NULL;
 	unsigned int num_hp = 0;
 	unsigned int i = 0;
@@ -1814,6 +1818,9 @@ eal_legacy_hugepage_attach(void)
 		struct hugepage_file *hf = &hp[i];
 		size_t map_sz = hf->size;
 		void *map_addr = hf->final_va;
+		int msl_idx, ms_idx;
+		struct rte_memseg_list *msl;
+		struct rte_memseg *ms;
 
 		/* if size is zero, no more pages left */
 		if (map_sz == 0)
@@ -1831,25 +1838,50 @@ eal_legacy_hugepage_attach(void)
 		if (map_addr == MAP_FAILED) {
 			RTE_LOG(ERR, EAL, "Could not map %s: %s\n",
 				hf->filepath, strerror(errno));
-			close(fd);
+			goto fd_error;
-			goto error;
 		}
 
 		/* set shared lock on the file. */
 		if (flock(fd, LOCK_SH) < 0) {
 			RTE_LOG(DEBUG, EAL, "%s(): Locking file failed: %s\n",
 				__func__, strerror(errno));
-			close(fd);
+			goto fd_error;
-			goto error;
 		}
 
-		close(fd);
+		/* find segment data */
+		msl = rte_mem_virt2memseg_list(map_addr);
+		if (msl == NULL) {
+			RTE_LOG(DEBUG, EAL, "%s(): Cannot find memseg list\n",
+				__func__);
+			goto fd_error;
+		}
+		ms = rte_mem_virt2memseg(map_addr, msl);
+		if (ms == NULL) {
+			RTE_LOG(DEBUG, EAL, "%s(): Cannot find memseg\n",
+				__func__);
+			goto fd_error;
+		}
+
+		msl_idx = msl - mcfg->memsegs;
+		ms_idx = rte_fbarray_find_idx(&msl->memseg_arr, ms);
+		if (ms_idx < 0) {
+			RTE_LOG(DEBUG, EAL, "%s(): Cannot find memseg idx\n",
+				__func__);
+			goto fd_error;
+		}
+
+		/* store segment fd internally */
+		if (eal_memalloc_set_seg_fd(msl_idx, ms_idx, fd) < 0)
+			RTE_LOG(ERR, EAL, "Could not store segment fd: %s\n",
+				rte_strerror(rte_errno));
 	}
 	/* unmap the hugepage config file, since we are done using it */
 	munmap(hp, size);
 	close(fd_hugepage);
 	return 0;
 
+fd_error:
+	close(fd);
 error:
 	/* map all segments into memory to make sure we get the addrs */
 	cur_seg = 0;