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authorNicholas Bellinger <nab@daterainc.com>2013-09-23 12:12:42 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2013-10-01 21:40:55 -0700
commit5f544cfac956971099e906f94568bc3fd1a7108a (patch)
tree01693c400aeae3cf1fbaf26b54f7b55e083387d3
parent15c03dd4859ab16f9212238f29dd315654aa94f6 (diff)
downloadop-kernel-dev-5f544cfac956971099e906f94568bc3fd1a7108a.zip
op-kernel-dev-5f544cfac956971099e906f94568bc3fd1a7108a.tar.gz
tcm_fc: Convert to per-cpu command map pre-allocation of ft_cmd
This patch converts tcm_fc to use transport_init_session_tags() pre-allocation logic for struct ft_cmd descriptors using per-cpu session tag pooling in order to effectively avoid memory allocation + release for each received I/O. It adds percpu_ida_alloc() in ft_recv_cmd() to obtain an tag and locate ft_cmd from se_sess->sess_cmd_map[], and percpu_ida_free() in ft_free_cmd() to release the tag based upon se_cmd->map_tag id. It also uses a TCM_FC_DEFAULT_TAGS value of 512, that puts the per se_sess->sess_cmd_map allocation at ~360K on 64-bit. v2 changes: - Handle possible tag < 0 failure with GFP_ATOMIC Cc: Mark Rustad <mark.d.rustad@intel.com> Cc: Robert Love <robert.w.love@intel.com> Cc: Kent Overstreet <kmo@daterainc.com> Signed-off-by: Nicholas Bellinger <nab@daterainc.com>
-rw-r--r--drivers/target/tcm_fc/tcm_fc.h1
-rw-r--r--drivers/target/tcm_fc/tfc_cmd.c18
-rw-r--r--drivers/target/tcm_fc/tfc_sess.c3
3 files changed, 17 insertions, 5 deletions
diff --git a/drivers/target/tcm_fc/tcm_fc.h b/drivers/target/tcm_fc/tcm_fc.h
index 0dd54a4..752863a 100644
--- a/drivers/target/tcm_fc/tcm_fc.h
+++ b/drivers/target/tcm_fc/tcm_fc.h
@@ -22,6 +22,7 @@
#define FT_NAMELEN 32 /* length of ASCII WWPNs including pad */
#define FT_TPG_NAMELEN 32 /* max length of TPG name */
#define FT_LUN_NAMELEN 32 /* max length of LUN name */
+#define TCM_FC_DEFAULT_TAGS 512 /* tags used for per-session preallocation */
struct ft_transport_id {
__u8 format;
diff --git a/drivers/target/tcm_fc/tfc_cmd.c b/drivers/target/tcm_fc/tfc_cmd.c
index 0e5a1cae..479ec56 100644
--- a/drivers/target/tcm_fc/tfc_cmd.c
+++ b/drivers/target/tcm_fc/tfc_cmd.c
@@ -28,6 +28,7 @@
#include <linux/configfs.h>
#include <linux/ctype.h>
#include <linux/hash.h>
+#include <linux/percpu_ida.h>
#include <asm/unaligned.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
@@ -89,16 +90,18 @@ static void ft_free_cmd(struct ft_cmd *cmd)
{
struct fc_frame *fp;
struct fc_lport *lport;
+ struct se_session *se_sess;
if (!cmd)
return;
+ se_sess = cmd->sess->se_sess;
fp = cmd->req_frame;
lport = fr_dev(fp);
if (fr_seq(fp))
lport->tt.seq_release(fr_seq(fp));
fc_frame_free(fp);
+ percpu_ida_free(&se_sess->sess_tag_pool, cmd->se_cmd.map_tag);
ft_sess_put(cmd->sess); /* undo get from lookup at recv */
- kfree(cmd);
}
void ft_release_cmd(struct se_cmd *se_cmd)
@@ -432,14 +435,21 @@ static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp)
{
struct ft_cmd *cmd;
struct fc_lport *lport = sess->tport->lport;
+ struct se_session *se_sess = sess->se_sess;
+ int tag;
- cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
- if (!cmd)
+ tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC);
+ if (tag < 0)
goto busy;
+
+ cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
+ memset(cmd, 0, sizeof(struct ft_cmd));
+
+ cmd->se_cmd.map_tag = tag;
cmd->sess = sess;
cmd->seq = lport->tt.seq_assign(lport, fp);
if (!cmd->seq) {
- kfree(cmd);
+ percpu_ida_free(&se_sess->sess_tag_pool, tag);
goto busy;
}
cmd->req_frame = fp; /* hold frame during cmd */
diff --git a/drivers/target/tcm_fc/tfc_sess.c b/drivers/target/tcm_fc/tfc_sess.c
index 4859505..ae52c08 100644
--- a/drivers/target/tcm_fc/tfc_sess.c
+++ b/drivers/target/tcm_fc/tfc_sess.c
@@ -210,7 +210,8 @@ static struct ft_sess *ft_sess_create(struct ft_tport *tport, u32 port_id,
if (!sess)
return NULL;
- sess->se_sess = transport_init_session();
+ sess->se_sess = transport_init_session_tags(TCM_FC_DEFAULT_TAGS,
+ sizeof(struct ft_cmd));
if (IS_ERR(sess->se_sess)) {
kfree(sess);
return NULL;
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