A new flag called _ODP_ISHM_LINK is added to _ishm. When this flag is
specified at reserve() time, a link ("/tmp/odp-<pid>-shm-<blockname>"
where <pid> is the process ID of the main ODP instatiation process and
<blockname> is the block name given at reserve time) is created, linking
to the underlying block file (either in /tmp or in hugetlbfs).
This link is meant to be used by processes external to ODP willing to
share this memory.
Signed-off-by: Christophe Milard <christophe.mil...@linaro.org>
---
platform/linux-generic/_ishm.c | 35 +++++++++++++++++++++++--
platform/linux-generic/include/_ishm_internal.h | 1 +
2 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/platform/linux-generic/_ishm.c b/platform/linux-generic/_ishm.c
index f4aa6d3..e6ceb24 100644
--- a/platform/linux-generic/_ishm.c
+++ b/platform/linux-generic/_ishm.c
@@ -99,6 +99,14 @@
#define ISHM_FILENAME_NORMAL_PAGE_DIR "/tmp"
/*
+ * when the memory is to be shared with an external entity (such as another
+ * ODP instance or an OS process not part of this ODP instance) then a
+ * link is created to the underlying filename: this defines the location
+ * and the format of this link name
+ */
+#define ISHM_LINKNAME_FORMAT "/tmp/odp-%d-shm-%s"
+
+/*
* At worse case the virtual space gets so fragmented that there is
* a unallocated fragment between each allocated fragment:
* In that case, the number of fragments to take care of is twice the
@@ -136,6 +144,7 @@ typedef struct ishm_fragment {
typedef struct ishm_block {
char name[ISHM_NAME_MAXLEN]; /* name for the ishm block (if any) */
char filename[ISHM_FILENAME_MAXLEN]; /* name of the .../odp-* file */
+ char linkname[ISHM_FILENAME_MAXLEN]; /* name of the /tmp/odp-* link */
int main_odpthread; /* The thread which did the initial reserve*/
uint32_t user_flags; /* any flags the user want to remember. */
uint32_t flags; /* block creation flags. */
@@ -380,7 +389,7 @@ static void free_fragment(ishm_fragment_t *fragmnt)
* or /mnt/huge/odp-<pid>-<sequence_or_name> (for huge pages)
* Return the new file descriptor, or -1 on error.
*/
-static int create_file(int block_index, int huge, uint64_t len)
+static int create_file(int block_index, int huge, uint64_t len, uint32_t flags)
{
char *name;
int fd;
@@ -429,6 +438,21 @@ static int create_file(int block_index, int huge, uint64_t
len)
strncpy(new_block->filename, filename, ISHM_FILENAME_MAXLEN - 1);
+ /* if _ODP_ISHM_LINK is set, create a symbolic link for external ref: */
+ if (flags & _ODP_ISHM_LINK) {
+ snprintf(new_block->linkname, ISHM_FILENAME_MAXLEN,
+ ISHM_LINKNAME_FORMAT,
+ odp_global_data.main_pid,
+ (name && name[0]) ? name : seq_string);
+ if (symlink(filename, new_block->linkname) < 0) {
+ ODP_ERR("symlink failed: err=%s.\n",
+ strerror(errno));
+ new_block->linkname[0] = 0;
+ }
+ } else {
+ new_block->linkname[0] = 0;
+ }
+
return fd;
}
@@ -456,7 +480,7 @@ static void *do_map(int block_index, uint64_t len, uint32_t
align,
* unless a fd was already given
*/
if (*fd < 0) {
- *fd = create_file(block_index, huge, len);
+ *fd = create_file(block_index, huge, len, flags);
if (*fd < 0)
return NULL;
} else {
@@ -472,6 +496,8 @@ static void *do_map(int block_index, uint64_t len, uint32_t
align,
close(*fd);
*fd = -1;
unlink(new_block->filename);
+ if (new_block->linkname[0])
+ unlink(new_block->linkname);
}
return NULL;
}
@@ -487,6 +513,8 @@ static void *do_map(int block_index, uint64_t len, uint32_t
align,
close(*fd);
*fd = -1;
unlink(new_block->filename);
+ if (new_block->linkname[0])
+ unlink(new_block->linkname);
}
return NULL;
}
@@ -870,6 +898,9 @@ static int block_free(int block_index)
/* remove the .../odp-* file, unless fd was external: */
if (block->filename[0] != 0)
unlink(block->filename);
+ /* also remove possible link: */
+ if (block->linkname[0] != 0)
+ unlink(block->linkname);
/* deregister the file descriptor from the file descriptor server. */
_odp_fdserver_deregister_fd(FD_SRV_CTX_ISHM, block_index);
diff --git a/platform/linux-generic/include/_ishm_internal.h
b/platform/linux-generic/include/_ishm_internal.h
index 3231b60..4fa6d9c 100644
--- a/platform/linux-generic/include/_ishm_internal.h
+++ b/platform/linux-generic/include/_ishm_internal.h
@@ -14,6 +14,7 @@ extern "C" {
/* flags available at ishm_reserve: */
#define _ODP_ISHM_SINGLE_VA 1
#define _ODP_ISHM_LOCK 2
+#define _ODP_ISHM_LINK 4 /*create soft link in /tmp */
/**
* Shared memory block info
--
2.7.4
