[Devel] [PATCH v2 2/2] fs/fuse kio: simplify processing and sending kio requests
Pavel Butsykin
pbutsykin at virtuozzo.com
Mon May 27 18:29:51 MSK 2019
This patch makes functions kpcs_req_classify() and pcs_fuse_submit() easier,
reducing the number of cases to handle kio requests.
Also, this patch allows us to get rid of the additional context switch, when
kio request is moved to cc->work_queue list under bg_lock. After this patch,
execution of kpcs_req_send() is available only without fc->bg_lock.
Signed-off-by: Pavel Butsykin <pbutsykin at virtuozzo.com>
---
fs/fuse/dev.c | 24 ++++++-----
fs/fuse/fuse_i.h | 2 +-
fs/fuse/kio/pcs/pcs_fuse_kdirect.c | 84 +++++++++++++-------------------------
3 files changed, 43 insertions(+), 67 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 3e0fecbe8db3..b8a524f04298 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -393,9 +393,11 @@ void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
static void flush_bg_queue(struct fuse_conn *fc, struct fuse_iqueue *fiq)
{
+ struct fuse_req *req, *next;
+ LIST_HEAD(kio_reqs);
+
while (fc->active_background < fc->max_background &&
!list_empty(&fc->bg_queue)) {
- struct fuse_req *req;
req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
list_del_init(&req->list);
@@ -404,16 +406,24 @@ static void flush_bg_queue(struct fuse_conn *fc, struct fuse_iqueue *fiq)
if (fc->kio.op) {
int ret = fc->kio.op->req_classify(fc, req, true, true);
if (likely(!ret)) {
- fc->kio.op->req_send(fc, req, NULL, true, true);
+ list_add_tail(&req->list, &kio_reqs);
continue;
} else if (ret < 0)
continue;
}
+
spin_lock(&fiq->waitq.lock);
req->in.h.unique = fuse_get_unique(fiq);
queue_request(fiq, req);
spin_unlock(&fiq->waitq.lock);
}
+
+ spin_unlock(&fc->bg_lock);
+ list_for_each_entry_safe(req, next, &kio_reqs, list) {
+ list_del_init(&req->list);
+ fc->kio.op->req_send(fc, req, NULL, true);
+ }
+ spin_lock(&fc->bg_lock);
}
/*
@@ -563,7 +573,7 @@ static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req,
if (fc->kio.op) {
int ret = fc->kio.op->req_classify(fc, req, false, false);
if (likely(!ret))
- return fc->kio.op->req_send(fc, req, ff, false, false);
+ return fc->kio.op->req_send(fc, req, ff, false);
else if (ret < 0)
return;
}
@@ -656,14 +666,6 @@ void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
{
WARN_ON(!req->end);
- if (fc->kio.op) {
- int ret = fc->kio.op->req_classify(fc, req, true, false);
- if (likely(!ret))
- return fc->kio.op->req_send(fc, req, NULL, true, false);
- else if (ret < 0)
- return;
- }
-
if (!fuse_request_queue_background(fc, req)) {
if (!req->out.h.error)
req->out.h.error = -ENOTCONN;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 7978a1d891d2..34a4317a9689 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -530,7 +530,7 @@ struct fuse_kio_ops {
int (*req_classify)(struct fuse_conn *fc, struct fuse_req *req, bool bg,
bool locked);
void (*req_send)(struct fuse_conn *fc, struct fuse_req *req,
- struct fuse_file *ff, bool bg, bool locked);
+ struct fuse_file *ff, bool bg);
/* Inode scope hooks */
int (*file_open)(struct fuse_conn *fc, struct file *file,
diff --git a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
index a101d3950373..51e45911d6b8 100644
--- a/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
+++ b/fs/fuse/kio/pcs/pcs_fuse_kdirect.c
@@ -947,7 +947,7 @@ out:
}
static void pcs_fuse_submit(struct pcs_fuse_cluster *pfc, struct fuse_req *req,
- struct fuse_file *ff, bool async, bool lk)
+ struct fuse_file *ff)
{
struct pcs_fuse_req *r = pcs_req_from_fuse(req);
struct fuse_inode *fi = get_fuse_inode(req->io_inode);
@@ -1040,11 +1040,7 @@ static void pcs_fuse_submit(struct pcs_fuse_cluster *pfc, struct fuse_req *req,
error:
DTRACE("do fuse_request_end req:%p op:%d err:%d\n", req, req->in.h.opcode, req->out.h.error);
- if (lk)
- spin_unlock(&pfc->fc->bg_lock);
request_end(pfc->fc, req);
- if (lk)
- spin_lock(&pfc->fc->bg_lock);
return;
submit:
@@ -1052,11 +1048,7 @@ submit:
req->out.h.error = -EIO;
goto error;
}
-
- if (async)
- pcs_cc_submit(ireq->cc, ireq);
- else
- ireq_process(ireq);
+ ireq_process(ireq);
}
static void kpcs_setattr_end(struct fuse_conn *fc, struct fuse_req *req)
@@ -1119,7 +1111,7 @@ static void _pcs_shrink_end(struct fuse_conn *fc, struct fuse_req *req)
TRACE("resubmit %p\n", &r->req);
list_del_init(&ireq->list);
- pcs_fuse_submit(pfc, &r->req, r->req.ff, true, false);
+ pcs_fuse_submit(pfc, &r->req, r->req.ff);
}
}
@@ -1232,64 +1224,46 @@ static int kpcs_req_classify(struct fuse_conn* fc, struct fuse_req *req,
return 1;
BUG_ON(!pfc);
- /* At this point request can not belongs to any list
- * so we can avoid grab fc->lock here at all.
- */
- BUG_ON(!list_empty(&req->list));
-
DTRACE("Classify req:%p op:%d end:%p bg:%d lk:%d\n", req, req->in.h.opcode,
req->end, bg, lk);
ret = pcs_kio_classify_req(fc, req, lk);
- if (ret) {
- if (ret < 0) {
- if (!bg)
- atomic_inc(&req->count);
- __clear_bit(FR_PENDING, &req->flags);
- req->out.h.error = ret;
- if (lk)
- spin_unlock(&fc->bg_lock);
- request_end(fc, req);
- if (lk)
- spin_lock(&fc->bg_lock);
- return ret;
- }
- return 1;
- }
+ if (likely(!ret))
+ return 0;
- if (!lk) {
- spin_lock(&fc->bg_lock);
- if (fc->num_background + 1 >= fc->max_background ||
- !fc->connected) {
+ if (ret < 0) {
+ if (!bg)
+ atomic_inc(&req->count);
+ __clear_bit(FR_PENDING, &req->flags);
+ req->out.h.error = ret;
+ if (lk)
spin_unlock(&fc->bg_lock);
- return 1;
- }
- fc->num_background++;
- fc->active_background++;
-
- if (fc->num_background == fc->congestion_threshold &&
- fc->bdi_initialized) {
- set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
- set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
- }
- spin_unlock(&fc->bg_lock);
+ request_end(fc, req);
+ if (lk)
+ spin_lock(&fc->bg_lock);
+ return ret;
}
- return 0;
+ return 1;
}
static void kpcs_req_send(struct fuse_conn* fc, struct fuse_req *req,
- struct fuse_file *ff, bool bg, bool lk)
+ struct fuse_file *ff, bool bg)
{
- struct pcs_fuse_cluster *pfc = (struct pcs_fuse_cluster*)fc->kio.ctx;
+ struct pcs_fuse_cluster *pfc = (struct pcs_fuse_cluster*)fc->kio.ctx;
- TRACE("Send req:%p op:%d end:%p bg:%d lk:%d\n",
- req, req->in.h.opcode, req->end, bg, lk);
+ /* At this point request can not belongs to any list
+ * so we can avoid grab fc->lock here at all.
+ */
+ BUG_ON(!list_empty(&req->list));
- /* request_end below will do fuse_put_request() */
- if (!bg)
- atomic_inc(&req->count);
+ TRACE("Send req:%p op:%d end:%p bg:%d\n",
+ req, req->in.h.opcode, req->end, bg);
+
+ /* request_end below will do fuse_put_request() */
+ if (!bg)
+ atomic_inc(&req->count);
__clear_bit(FR_PENDING, &req->flags);
- pcs_fuse_submit(pfc, req, ff ? : req->ff, lk, lk);
+ pcs_fuse_submit(pfc, req, ff ? : req->ff);
if (!bg)
wait_event(req->waitq,
test_bit(FR_FINISHED, &req->flags) && !req->end);
--
2.15.1
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