Re: [PATCH linux-2.6.36-rc7] sunrpc/xprtrdma: clean up workqueueusage

From: Tom Tucker
Date: Fri Oct 15 2010 - 13:47:08 EST


On 10/15/10 12:11 PM, J. Bruce Fields wrote:
Tom, could you take a look?

This looks reasonable to me.

My bet is that it wasn't tested though due to hardware availability. I'll test it this weekend and let you know how it goes.

Tom
--b.

On Fri, Oct 15, 2010 at 05:49:27PM +0200, Tejun Heo wrote:
* Create and use svc_rdma_wq instead of using the system workqueue and
flush_scheduled_work(). This workqueue is necessary to serve as
flushing domain for rdma->sc_work which is used to destroy itself
and thus can't be flushed explicitly.

* Replace cancel_delayed_work() + flush_scheduled_work() with
cancel_delayed_work_sync().

* Implement synchronous connect in xprt_rdma_connect() using
flush_delayed_work() on the rdma_connect work instead of using
flush_scheduled_work().

This is to prepare for the deprecation and removal of
flush_scheduled_work().

Signed-off-by: Tejun Heo<tj@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/svc_rdma.c | 11 ++++++++++-
net/sunrpc/xprtrdma/svc_rdma_transport.c | 6 +++++-
net/sunrpc/xprtrdma/transport.c | 5 ++---
3 files changed, 17 insertions(+), 5 deletions(-)

Index: work/net/sunrpc/xprtrdma/svc_rdma.c
===================================================================
--- work.orig/net/sunrpc/xprtrdma/svc_rdma.c
+++ work/net/sunrpc/xprtrdma/svc_rdma.c
@@ -43,6 +43,7 @@
#include<linux/slab.h>
#include<linux/fs.h>
#include<linux/sysctl.h>
+#include<linux/workqueue.h>
#include<linux/sunrpc/clnt.h>
#include<linux/sunrpc/sched.h>
#include<linux/sunrpc/svc_rdma.h>
@@ -74,6 +75,8 @@ atomic_t rdma_stat_sq_prod;
struct kmem_cache *svc_rdma_map_cachep;
struct kmem_cache *svc_rdma_ctxt_cachep;

+struct workqueue_struct *svc_rdma_wq;
+
/*
* This function implements reading and resetting an atomic_t stat
* variable through read/write to a proc file. Any write to the file
@@ -231,7 +234,7 @@ static ctl_table svcrdma_root_table[] =
void svc_rdma_cleanup(void)
{
dprintk("SVCRDMA Module Removed, deregister RPC RDMA transport\n");
- flush_scheduled_work();
+ destroy_workqueue(svc_rdma_wq);
if (svcrdma_table_header) {
unregister_sysctl_table(svcrdma_table_header);
svcrdma_table_header = NULL;
@@ -249,6 +252,11 @@ int svc_rdma_init(void)
dprintk("\tsq_depth : %d\n",
svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT);
dprintk("\tmax_inline : %d\n", svcrdma_max_req_size);
+
+ svc_rdma_wq = alloc_workqueue("svc_rdma", 0, 0);
+ if (!svc_rdma_wq)
+ return -ENOMEM;
+
if (!svcrdma_table_header)
svcrdma_table_header =
register_sysctl_table(svcrdma_root_table);
@@ -283,6 +291,7 @@ int svc_rdma_init(void)
kmem_cache_destroy(svc_rdma_map_cachep);
err0:
unregister_sysctl_table(svcrdma_table_header);
+ destroy_workqueue(svc_rdma_wq);
return -ENOMEM;
}
MODULE_AUTHOR("Tom Tucker<tom@xxxxxxxxxxxxxxxxxxxxx>");
Index: work/net/sunrpc/xprtrdma/svc_rdma_transport.c
===================================================================
--- work.orig/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ work/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -45,6 +45,7 @@
#include<linux/sched.h>
#include<linux/slab.h>
#include<linux/spinlock.h>
+#include<linux/workqueue.h>
#include<rdma/ib_verbs.h>
#include<rdma/rdma_cm.h>
#include<linux/sunrpc/svc_rdma.h>
@@ -89,6 +90,9 @@ struct svc_xprt_class svc_rdma_class = {
/* WR context cache. Created in svc_rdma.c */
extern struct kmem_cache *svc_rdma_ctxt_cachep;

+/* Workqueue created in svc_rdma.c */
+extern struct workqueue_struct *svc_rdma_wq;
+
struct svc_rdma_op_ctxt *svc_rdma_get_context(struct svcxprt_rdma *xprt)
{
struct svc_rdma_op_ctxt *ctxt;
@@ -1184,7 +1188,7 @@ static void svc_rdma_free(struct svc_xpr
struct svcxprt_rdma *rdma =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
INIT_WORK(&rdma->sc_work, __svc_rdma_free);
- schedule_work(&rdma->sc_work);
+ queue_work(svc_rdma_wq,&rdma->sc_work);
}

static int svc_rdma_has_wspace(struct svc_xprt *xprt)
Index: work/net/sunrpc/xprtrdma/transport.c
===================================================================
--- work.orig/net/sunrpc/xprtrdma/transport.c
+++ work/net/sunrpc/xprtrdma/transport.c
@@ -237,8 +237,7 @@ xprt_rdma_destroy(struct rpc_xprt *xprt)

dprintk("RPC: %s: called\n", __func__);

- cancel_delayed_work(&r_xprt->rdma_connect);
- flush_scheduled_work();
+ cancel_delayed_work_sync(&r_xprt->rdma_connect);

xprt_clear_connected(xprt);

@@ -460,7 +459,7 @@ xprt_rdma_connect(struct rpc_task *task)
} else {
schedule_delayed_work(&r_xprt->rdma_connect, 0);
if (!RPC_IS_ASYNC(task))
- flush_scheduled_work();
+ flush_delayed_work(&r_xprt->rdma_connect);
}
}

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