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authorShyam Prasad N <sprasad@microsoft.com>2022-12-26 11:24:56 +0000
committerSteve French <stfrench@microsoft.com>2023-11-09 10:25:17 -0600
commita6d8fb54a515f0546ffdb7870102b1238917e567 (patch)
tree7e3d5020ea3e68e21d8373b687205a2815c8a102 /fs/smb/client/sess.c
parent0c51cc6f2cb0108e7d49805f6e089cd85caab279 (diff)
cifs: distribute channels across interfaces based on speed
Today, if the server interfaces RSS capable, we simply choose the fastest interface to setup a channel. This is not a scalable approach, and does not make a lot of attempt to distribute the connections. This change does a weighted distribution of channels across all the available server interfaces, where the weight is a function of the advertised interface speed. Also make sure that we don't mix rdma and non-rdma for channels. Signed-off-by: Shyam Prasad N <sprasad@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/smb/client/sess.c')
-rw-r--r--fs/smb/client/sess.c84
1 files changed, 70 insertions, 14 deletions
diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c
index d13a24613710..336b64d93e41 100644
--- a/fs/smb/client/sess.c
+++ b/fs/smb/client/sess.c
@@ -179,7 +179,9 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
int left;
int rc = 0;
int tries = 0;
+ size_t iface_weight = 0, iface_min_speed = 0;
struct cifs_server_iface *iface = NULL, *niface = NULL;
+ struct cifs_server_iface *last_iface = NULL;
spin_lock(&ses->chan_lock);
@@ -207,21 +209,11 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
}
spin_unlock(&ses->chan_lock);
- /*
- * Keep connecting to same, fastest, iface for all channels as
- * long as its RSS. Try next fastest one if not RSS or channel
- * creation fails.
- */
- spin_lock(&ses->iface_lock);
- iface = list_first_entry(&ses->iface_list, struct cifs_server_iface,
- iface_head);
- spin_unlock(&ses->iface_lock);
-
while (left > 0) {
tries++;
if (tries > 3*ses->chan_max) {
- cifs_dbg(FYI, "too many channel open attempts (%d channels left to open)\n",
+ cifs_dbg(VFS, "too many channel open attempts (%d channels left to open)\n",
left);
break;
}
@@ -229,17 +221,35 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
spin_lock(&ses->iface_lock);
if (!ses->iface_count) {
spin_unlock(&ses->iface_lock);
+ cifs_dbg(VFS, "server %s does not advertise interfaces\n",
+ ses->server->hostname);
break;
}
+ if (!iface)
+ iface = list_first_entry(&ses->iface_list, struct cifs_server_iface,
+ iface_head);
+ last_iface = list_last_entry(&ses->iface_list, struct cifs_server_iface,
+ iface_head);
+ iface_min_speed = last_iface->speed;
+
list_for_each_entry_safe_from(iface, niface, &ses->iface_list,
iface_head) {
+ /* do not mix rdma and non-rdma interfaces */
+ if (iface->rdma_capable != ses->server->rdma)
+ continue;
+
/* skip ifaces that are unusable */
if (!iface->is_active ||
(is_ses_using_iface(ses, iface) &&
- !iface->rss_capable)) {
+ !iface->rss_capable))
+ continue;
+
+ /* check if we already allocated enough channels */
+ iface_weight = iface->speed / iface_min_speed;
+
+ if (iface->weight_fulfilled >= iface_weight)
continue;
- }
/* take ref before unlock */
kref_get(&iface->refcount);
@@ -256,10 +266,21 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
continue;
}
- cifs_dbg(FYI, "successfully opened new channel on iface:%pIS\n",
+ iface->num_channels++;
+ iface->weight_fulfilled++;
+ cifs_dbg(VFS, "successfully opened new channel on iface:%pIS\n",
&iface->sockaddr);
break;
}
+
+ /* reached end of list. reset weight_fulfilled and start over */
+ if (list_entry_is_head(iface, &ses->iface_list, iface_head)) {
+ list_for_each_entry(iface, &ses->iface_list, iface_head)
+ iface->weight_fulfilled = 0;
+ spin_unlock(&ses->iface_lock);
+ iface = NULL;
+ continue;
+ }
spin_unlock(&ses->iface_lock);
left--;
@@ -278,8 +299,10 @@ int
cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
{
unsigned int chan_index;
+ size_t iface_weight = 0, iface_min_speed = 0;
struct cifs_server_iface *iface = NULL;
struct cifs_server_iface *old_iface = NULL;
+ struct cifs_server_iface *last_iface = NULL;
int rc = 0;
spin_lock(&ses->chan_lock);
@@ -299,13 +322,34 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
spin_unlock(&ses->chan_lock);
spin_lock(&ses->iface_lock);
+ if (!ses->iface_count) {
+ spin_unlock(&ses->iface_lock);
+ cifs_dbg(VFS, "server %s does not advertise interfaces\n", ses->server->hostname);
+ return 0;
+ }
+
+ last_iface = list_last_entry(&ses->iface_list, struct cifs_server_iface,
+ iface_head);
+ iface_min_speed = last_iface->speed;
+
/* then look for a new one */
list_for_each_entry(iface, &ses->iface_list, iface_head) {
+ /* do not mix rdma and non-rdma interfaces */
+ if (iface->rdma_capable != server->rdma)
+ continue;
+
if (!iface->is_active ||
(is_ses_using_iface(ses, iface) &&
!iface->rss_capable)) {
continue;
}
+
+ /* check if we already allocated enough channels */
+ iface_weight = iface->speed / iface_min_speed;
+
+ if (iface->weight_fulfilled >= iface_weight)
+ continue;
+
kref_get(&iface->refcount);
break;
}
@@ -321,10 +365,22 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
cifs_dbg(FYI, "replacing iface: %pIS with %pIS\n",
&old_iface->sockaddr,
&iface->sockaddr);
+
+ old_iface->num_channels--;
+ if (old_iface->weight_fulfilled)
+ old_iface->weight_fulfilled--;
+ iface->num_channels++;
+ iface->weight_fulfilled++;
+
kref_put(&old_iface->refcount, release_iface);
} else if (old_iface) {
cifs_dbg(FYI, "releasing ref to iface: %pIS\n",
&old_iface->sockaddr);
+
+ old_iface->num_channels--;
+ if (old_iface->weight_fulfilled)
+ old_iface->weight_fulfilled--;
+
kref_put(&old_iface->refcount, release_iface);
} else {
WARN_ON(!iface);