On 2011-09-10 10:41, Jim Rees wrote:
> From: Peng Tao <bergwolf@xxxxxxxxx>
Hi, I have a few comments inline below.
Otherwise, the direction and the patch looks good.
>
> For layoutdriver io done functions, default workqueue is not a good place as
> the code is executed in IO path. So add a pnfs private workqueue to handle
> them.
>
> Also change block and object layout code to make use of this private
> workqueue.
>
> Signed-off-by: Peng Tao <peng_tao@xxxxxxx>
> Signed-off-by: Jim Rees <rees@xxxxxxxxx>
> ---
> fs/nfs/blocklayout/blocklayout.c | 17 ++++++++---
> fs/nfs/objlayout/objio_osd.c | 8 ++++++
> fs/nfs/objlayout/objlayout.c | 4 +-
> fs/nfs/pnfs.c | 52 +++++++++++++++++++++++++++++++++++++-
> fs/nfs/pnfs.h | 4 +++
> 5 files changed, 77 insertions(+), 8 deletions(-)
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index dc23833..51f70f0 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -228,7 +228,7 @@ bl_end_par_io_read(void *data)
> struct nfs_read_data *rdata = data;
>
> INIT_WORK(&rdata->task.u.tk_work, bl_read_cleanup);
> - schedule_work(&rdata->task.u.tk_work);
> + pnfsiod_queue_work(&rdata->task.u.tk_work);
> }
>
> /* We don't want normal .rpc_call_done callback used, so we replace it
> @@ -418,7 +418,7 @@ static void bl_end_par_io_write(void *data)
> wdata->task.tk_status = 0;
> wdata->verf.committed = NFS_FILE_SYNC;
> INIT_WORK(&wdata->task.u.tk_work, bl_write_cleanup);
> - schedule_work(&wdata->task.u.tk_work);
> + pnfsiod_queue_work(&wdata->task.u.tk_work);
> }
>
> /* FIXME STUB - mark intersection of layout and page as bad, so is not
> @@ -981,29 +981,35 @@ static int __init nfs4blocklayout_init(void)
> if (ret)
> goto out;
>
> + ret = pnfsiod_start();
> + if (ret)
> + goto out_remove;
> +
> init_waitqueue_head(&bl_wq);
>
> mnt = rpc_get_mount();
> if (IS_ERR(mnt)) {
> ret = PTR_ERR(mnt);
> - goto out_remove;
> + goto out_stop;
> }
>
> ret = vfs_path_lookup(mnt->mnt_root,
> mnt,
> NFS_PIPE_DIRNAME, 0, &path);
> if (ret)
> - goto out_remove;
> + goto out_stop;
>
> bl_device_pipe = rpc_mkpipe(path.dentry, "blocklayout", NULL,
> &bl_upcall_ops, 0);
> if (IS_ERR(bl_device_pipe)) {
> ret = PTR_ERR(bl_device_pipe);
> - goto out_remove;
> + goto out_stop;
> }
> out:
> return ret;
>
> +out_stop:
> + pnfsiod_stop();
> out_remove:
> pnfs_unregister_layoutdriver(&blocklayout_type);
> return ret;
> @@ -1015,6 +1021,7 @@ static void __exit nfs4blocklayout_exit(void)
> __func__);
>
> pnfs_unregister_layoutdriver(&blocklayout_type);
> + pnfsiod_stop();
> rpc_unlink(bl_device_pipe);
> }
>
> diff --git a/fs/nfs/objlayout/objio_osd.c b/fs/nfs/objlayout/objio_osd.c
> index d0cda12..f28013f 100644
> --- a/fs/nfs/objlayout/objio_osd.c
> +++ b/fs/nfs/objlayout/objio_osd.c
> @@ -1042,7 +1042,14 @@ static int __init
> objlayout_init(void)
> {
> int ret = pnfs_register_layoutdriver(&objlayout_type);
> + if (ret)
> + goto out;
>
> + ret = pnfsiod_start();
> + if (ret)
> + pnfs_unregister_layoutdriver(&objlayout_type);
> +
> +out:
> if (ret)
> printk(KERN_INFO
> "%s: Registering OSD pNFS Layout Driver failed: error=%d\n",
> @@ -1057,6 +1064,7 @@ static void __exit
> objlayout_exit(void)
> {
> pnfs_unregister_layoutdriver(&objlayout_type);
> + pnfsiod_stop();
> printk(KERN_INFO "%s: Unregistered OSD pNFS Layout Driver\n",
> __func__);
> }
> diff --git a/fs/nfs/objlayout/objlayout.c b/fs/nfs/objlayout/objlayout.c
> index 1d06f8e..f7c6c21 100644
> --- a/fs/nfs/objlayout/objlayout.c
> +++ b/fs/nfs/objlayout/objlayout.c
> @@ -305,7 +305,7 @@ objlayout_read_done(struct objlayout_io_state *state, ssize_t status, bool sync)
> pnfs_ld_read_done(rdata);
> else {
> INIT_WORK(&rdata->task.u.tk_work, _rpc_read_complete);
> - schedule_work(&rdata->task.u.tk_work);
> + pnfsiod_queue_work(&rdata->task.u.tk_work);
> }
> }
>
> @@ -396,7 +396,7 @@ objlayout_write_done(struct objlayout_io_state *state, ssize_t status,
> pnfs_ld_write_done(wdata);
> else {
> INIT_WORK(&wdata->task.u.tk_work, _rpc_write_complete);
> - schedule_work(&wdata->task.u.tk_work);
> + pnfsiod_queue_work(&wdata->task.u.tk_work);
> }
> }
>
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index e550e88..5ac7a78 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -38,7 +38,7 @@
> /* Locking:
> *
> * pnfs_spinlock:
> - * protects pnfs_modules_tbl.
> + * protects pnfs_modules_tbl, pnfsiod_workqueue and pnfsiod_users.
> */
> static DEFINE_SPINLOCK(pnfs_spinlock);
>
> @@ -47,6 +47,9 @@ static DEFINE_SPINLOCK(pnfs_spinlock);
> */
> static LIST_HEAD(pnfs_modules_tbl);
>
> +static struct workqueue_struct *pnfsiod_workqueue;
> +static int pnfsiod_users = 0;
There's no need to initialize static variables to zero.
> +
> /* Return the registered pnfs layout driver module matching given id */
> static struct pnfs_layoutdriver_type *
> find_pnfs_driver_locked(u32 id)
> @@ -1478,3 +1481,50 @@ out:
> dprintk("<-- %s status %d\n", __func__, status);
> return status;
> }
> +
> +/*
> + * start up the pnfsiod workqueue
> + */
> +int pnfsiod_start(void)
> +{
> + struct workqueue_struct *wq;
> + dprintk("RPC: creating workqueue pnfsiod\n");
hmm, s/RPC/NFS/ this is not the RPC module any more :)
looks like a cut'n'paste from rpciod_start...
> + wq = alloc_workqueue("pnfsiod", WQ_MEM_RECLAIM, 0);
> + if (wq == NULL)
> + return -ENOMEM;
> + spin_lock(&pnfs_spinlock);
> + pnfsiod_users++;
> + if (pnfsiod_workqueue == NULL) {
> + pnfsiod_workqueue = wq;
> + } else {
> + destroy_workqueue(wq);
> + }
The curly braces in this statement are an overkill
(and deviation from CodingStyle)
> + spin_unlock(&pnfs_spinlock);
> + return 0;
although this way of accounting is ultimately simple
it's wasteful and since we're not really expecting any concurrent
calls to this function. I'd consider coding this it as follows:
atomic_inc(&pnfsiod_users);
if (pnfsiod_workqueue == NULL) {
wq = alloc_workqueue("pnfsiod", WQ_MEM_RECLAIM, 0);
if (wq == NULL)
return -ENOMEM;
spin_lock(&pnfs_spinlock);
if (pnfsiod_workqueue == NULL)
pnfsiod_workqueue = wq;
else
destroy_workqueue(wq);
spin_unlock(&pnfs_spinlock);
}
return 0;
> +}
> +EXPORT_SYMBOL_GPL(pnfsiod_start);
> +
> +/*
> + * Destroy the pnfsiod workqueue
> + */
> +void pnfsiod_stop(void)
> +{
> + struct workqueue_struct *wq = NULL;
> +
> + spin_lock(&pnfs_spinlock);
> + pnfsiod_users--;
> + if (pnfsiod_users == 0) {
> + wq = pnfsiod_workqueue;
> + pnfsiod_workqueue = NULL;
> + }
> + spin_unlock(&pnfs_spinlock);
> + if (wq)
> + destroy_workqueue(wq);
and continuing my proposal from above:
if (atomic_dec_and_lock(&pnfsiod_users)) {
wq = pnfsiod_workqueue;
pnfsiod_workqueue = NULL;
spin_unlock(&pnfs_spinlock);
}
if (wq)
destroy_workqueue(wq);
Benny
> +}
> +EXPORT_SYMBOL_GPL(pnfsiod_stop);
> +
> +void pnfsiod_queue_work(struct work_struct* work)
> +{
> + queue_work(pnfsiod_workqueue, work);
> +}
> +EXPORT_SYMBOL_GPL(pnfsiod_queue_work);
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index 01cbfd5..bc1eed5 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -165,6 +165,10 @@ extern int nfs4_proc_layoutget(struct nfs4_layoutget *lgp);
> extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp);
>
> /* pnfs.c */
> +int pnfsiod_start(void);
> +void pnfsiod_stop(void);
> +void pnfsiod_queue_work(struct work_struct* work);
> +
> void get_layout_hdr(struct pnfs_layout_hdr *lo);
> void put_lseg(struct pnfs_layout_segment *lseg);
>
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