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Subject[PATCH v2 4/6] 9p: Embed wait_queue_head into p9_req_t
Date
On a 64-bit system, the wait_queue_head_t is 24 bytes while the pointer
to it is 8 bytes. Growing the p9_req_t by 16 bytes is better than
performing a 24-byte memory allocation.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
include/net/9p/client.h | 2 +-
net/9p/client.c | 19 +++++--------------
net/9p/trans_virtio.c | 2 +-
3 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index e405729cd1c7..0fa0fbab33b0 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -113,7 +113,7 @@ enum p9_req_status_t {
struct p9_req_t {
int status;
int t_err;
- wait_queue_head_t *wq;
+ wait_queue_head_t wq;
struct p9_fcall *tc;
struct p9_fcall *rc;
void *aux;
diff --git a/net/9p/client.c b/net/9p/client.c
index b89c7298267c..bc8aba6b5ce0 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -282,8 +282,9 @@ p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
return ERR_PTR(-ENOMEM);
}
for (col = 0; col < P9_ROW_MAXTAG; col++) {
- c->reqs[row][col].status = REQ_STATUS_IDLE;
- c->reqs[row][col].tc = NULL;
+ req = &c->reqs[row][col];
+ req->status = REQ_STATUS_IDLE;
+ init_waitqueue_head(&req->wq);
}
c->max_tag += P9_ROW_MAXTAG;
}
@@ -293,13 +294,6 @@ p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
col = tag % P9_ROW_MAXTAG;

req = &c->reqs[row][col];
- if (!req->wq) {
- req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
- if (!req->wq)
- goto grow_failed;
- init_waitqueue_head(req->wq);
- }
-
if (!req->tc)
req->tc = p9_fcall_alloc(alloc_msize);
if (!req->rc)
@@ -319,9 +313,7 @@ p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
pr_err("Couldn't grow tag array\n");
kfree(req->tc);
kfree(req->rc);
- kfree(req->wq);
req->tc = req->rc = NULL;
- req->wq = NULL;
return ERR_PTR(-ENOMEM);
}

@@ -409,7 +401,6 @@ static void p9_tag_cleanup(struct p9_client *c)
/* free requests associated with tags */
for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
for (col = 0; col < P9_ROW_MAXTAG; col++) {
- kfree(c->reqs[row][col].wq);
kfree(c->reqs[row][col].tc);
kfree(c->reqs[row][col].rc);
}
@@ -452,7 +443,7 @@ void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
smp_wmb();
req->status = status;

- wake_up(req->wq);
+ wake_up(&req->wq);
p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
}
EXPORT_SYMBOL(p9_client_cb);
@@ -773,7 +764,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
}
again:
/* Wait for the response */
- err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
+ err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);

/*
* Make sure our req is coherent with regard to updates in other
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 05006cbb3361..3e096c98313c 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -490,7 +490,7 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
virtqueue_kick(chan->vq);
spin_unlock_irqrestore(&chan->lock, flags);
p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
- err = wait_event_killable(*req->wq, req->status >= REQ_STATUS_RCVD);
+ err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
/*
* Non kernel buffers are pinned, unpin them
*/
--
2.18.0
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