Patchwork [3/6] This patch converts v9fs_read() to make use of the threadlets infrastructure.

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Submitter Arun Bharadwaj
Date Oct. 13, 2010, 3:37 p.m.
Message ID <20101013153706.21873.29799.stgit@localhost6.localdomain6>
Download mbox | patch
Permalink /patch/67695/
State New
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Comments

Arun Bharadwaj - Oct. 13, 2010, 3:37 p.m.
From: Gautham R Shenoy <ego@in.ibm.com>

This patch offloads all the blocking calls invoked for v9fs_read onto the
helper threads belonging to the threadlets infrastructure. The handling of
the v9fs_post_*read* calls is done from the io-thread context.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Arun R Bharadwaj <arun@linux.vnet.ibm.com>
---
 hw/virtio-9p.c |  218 +++++++++++++++++++++++++++++++++++++++++---------------
 hw/virtio-9p.h |    5 +
 2 files changed, 164 insertions(+), 59 deletions(-)

Patch

diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index cf7e012..da185c3 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -2037,33 +2037,136 @@  out:
     complete_pdu(s, pdu, err);
 }
 
-static void v9fs_read_post_readdir(V9fsState *, V9fsReadState *, ssize_t);
+/********************** v9fs_read calls ******************************/
+static void v9fs_read_do_preadv(ThreadletWork *work)
+{
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    v9fs_do_preadv(vs->s, vs->fidp->fs.fd, vs->sg, vs->cnt, vs->off);
+    vs->v9fs_errno = errno;
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_rewinddir(ThreadletWork *work)
+ {
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    v9fs_do_rewinddir(vs->s, vs->fidp->fs.dir);
+    vs->v9fs_errno = errno;
 
-static void v9fs_read_post_seekdir(V9fsState *s, V9fsReadState *vs, ssize_t err)
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_lseek(ThreadletWork *work)
 {
-    if (err) {
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    vs->err = v9fs_do_lseek(vs->s, vs->fidp->fs.fd, vs->off, SEEK_SET);
+    vs->v9fs_errno = errno;
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_readv(ThreadletWork *work)
+{
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    do {
+        if (0) {
+            print_sg(vs->sg, vs->cnt);
+        }
+        vs->len = v9fs_do_readv(vs->s, vs->fidp->fs.fd, vs->sg, vs->cnt);
+    } while (vs->len == -1 && errno == EINTR);
+    vs->v9fs_errno = errno;
+
+    if (vs->len == -1) {
+        vs->err  = -vs->v9fs_errno;
+    }
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_telldir(ThreadletWork *work)
+{
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    vs->dir_pos = v9fs_do_telldir(vs->s, vs->fidp->fs.dir);
+    vs->v9fs_errno = errno;
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_readdir(ThreadletWork *work)
+{
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    vs->dent = v9fs_do_readdir(vs->s, vs->fidp->fs.dir);
+    vs->v9fs_errno = errno;
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_lstat(ThreadletWork *work)
+{
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    vs->err = v9fs_do_lstat(vs->s, &vs->name, &vs->stbuf);
+    vs->v9fs_errno = errno;
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+static void v9fs_read_do_seekdir(ThreadletWork *work)
+{
+    V9fsReadState *vs;
+
+    vs = container_of(work, V9fsReadState, work);
+    v9fs_do_seekdir(vs->s, vs->fidp->fs.dir, vs->dir_pos);
+    vs->v9fs_errno = errno;
+
+    v9fs_async_helper_done(vs->post_fn, vs);
+}
+
+
+
+static void v9fs_read_post_readdir(void *);
+
+static void v9fs_read_post_seekdir(void *opaque)
+{
+    V9fsReadState *vs = (V9fsReadState *)opaque;
+
+    if (vs->err) {
         goto out;
     }
     v9fs_stat_free(&vs->v9stat);
     v9fs_string_free(&vs->name);
     vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->count);
     vs->offset += vs->count;
-    err = vs->offset;
+    vs->err = vs->offset;
 out:
-    complete_pdu(s, vs->pdu, err);
+    complete_pdu(vs->s, vs->pdu, vs->err);
     qemu_free(vs);
     return;
 }
 
-static void v9fs_read_post_dir_lstat(V9fsState *s, V9fsReadState *vs,
-                                    ssize_t err)
+static void v9fs_read_post_dir_lstat(void *opaque)
 {
-    if (err) {
-        err = -errno;
+    V9fsReadState *vs = (V9fsReadState *)opaque;
+
+    if (vs->err) {
+        vs->err = -vs->v9fs_errno;
         goto out;
     }
-    err = stat_to_v9stat(s, &vs->name, &vs->stbuf, &vs->v9stat);
-    if (err) {
+    vs->err = stat_to_v9stat(vs->s, &vs->name, &vs->stbuf, &vs->v9stat);
+    if (vs->err) {
         goto out;
     }
 
@@ -2071,26 +2174,28 @@  static void v9fs_read_post_dir_lstat(V9fsState *s, V9fsReadState *vs,
                             &vs->v9stat);
     if ((vs->len != (vs->v9stat.size + 2)) ||
             ((vs->count + vs->len) > vs->max_count)) {
-        v9fs_do_seekdir(s, vs->fidp->fs.dir, vs->dir_pos);
-        v9fs_read_post_seekdir(s, vs, err);
+        v9fs_do_async_posix(&vs->work, v9fs_read_do_seekdir, &vs->post_fn,
+                            v9fs_read_post_seekdir);
         return;
     }
     vs->count += vs->len;
     v9fs_stat_free(&vs->v9stat);
     v9fs_string_free(&vs->name);
     vs->dir_pos = vs->dent->d_off;
-    vs->dent = v9fs_do_readdir(s, vs->fidp->fs.dir);
-    v9fs_read_post_readdir(s, vs, err);
+    v9fs_do_async_posix(&vs->work, v9fs_read_do_readdir, &vs->post_fn,
+                        v9fs_read_post_readdir);
     return;
 out:
-    v9fs_do_seekdir(s, vs->fidp->fs.dir, vs->dir_pos);
-    v9fs_read_post_seekdir(s, vs, err);
+    v9fs_do_async_posix(&vs->work, v9fs_read_do_seekdir, &vs->post_fn,
+                        v9fs_read_post_seekdir);
     return;
 
 }
 
-static void v9fs_read_post_readdir(V9fsState *s, V9fsReadState *vs, ssize_t err)
+static void v9fs_read_post_readdir(void *opaque)
 {
+    V9fsReadState *vs = (V9fsReadState *)opaque;
+
     if (vs->dent) {
         memset(&vs->v9stat, 0, sizeof(vs->v9stat));
         v9fs_string_init(&vs->name);
@@ -2098,64 +2203,61 @@  static void v9fs_read_post_readdir(V9fsState *s, V9fsReadState *vs, ssize_t err)
                             vs->dent->d_name);
         err = v9fs_do_lstat(s, &vs->name, &vs->stbuf);
         v9fs_read_post_dir_lstat(s, vs, err);
+        v9fs_do_async_posix(&vs->work, v9fs_read_do_lstat, &vs->post_fn,
+                            v9fs_read_post_dir_lstat);
         return;
     }
 
     vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->count);
     vs->offset += vs->count;
-    err = vs->offset;
-    complete_pdu(s, vs->pdu, err);
+    vs->err = vs->offset;
+    complete_pdu(vs->s, vs->pdu, vs->err);
     qemu_free(vs);
     return;
 }
 
-static void v9fs_read_post_telldir(V9fsState *s, V9fsReadState *vs, ssize_t err)
+static void v9fs_read_post_telldir(void *opaque)
 {
-    vs->dent = v9fs_do_readdir(s, vs->fidp->fs.dir);
-    v9fs_read_post_readdir(s, vs, err);
+    V9fsReadState *vs = (V9fsReadState *)opaque;
+
+    v9fs_do_async_posix(&vs->work, v9fs_read_do_readdir, &vs->post_fn,
+                        v9fs_read_post_readdir);
     return;
 }
 
-static void v9fs_read_post_rewinddir(V9fsState *s, V9fsReadState *vs,
-                                       ssize_t err)
+static void v9fs_read_post_rewinddir(void *opaque)
 {
-    vs->dir_pos = v9fs_do_telldir(s, vs->fidp->fs.dir);
-    v9fs_read_post_telldir(s, vs, err);
+    V9fsReadState *vs = (V9fsReadState *)opaque;
+
+    v9fs_do_async_posix(&vs->work, v9fs_read_do_telldir, &vs->post_fn,
+                        v9fs_read_post_telldir);
     return;
 }
 
-static void v9fs_read_post_preadv(V9fsState *s, V9fsReadState *vs, ssize_t err)
+static void v9fs_read_post_preadv(void *opaque)
 {
-    if (err  < 0) {
+    V9fsReadState *vs = (V9fsReadState *)opaque;
+
+    if (vs->err  < 0) {
         /* IO error return the error */
-        err = -errno;
+        vs->err = -errno;
         goto out;
+    } else {
+        vs->off += vs->len;
     }
     vs->total += vs->len;
     vs->sg = adjust_sg(vs->sg, vs->len, &vs->cnt);
     if (vs->total < vs->count && vs->len > 0) {
-        do {
-            if (0) {
-                print_sg(vs->sg, vs->cnt);
-            }
-            vs->len = v9fs_do_preadv(s, vs->fidp->fs.fd, vs->sg, vs->cnt,
-                      vs->off);
-            if (vs->len > 0) {
-                vs->off += vs->len;
-            }
-        } while (vs->len == -1 && errno == EINTR);
-        if (vs->len == -1) {
-            err  = -errno;
-        }
-        v9fs_read_post_preadv(s, vs, err);
+        v9fs_do_async_posix(&vs->work, v9fs_read_do_preadv, &vs->post_fn,
+                            v9fs_read_post_preadv);
         return;
     }
     vs->offset += pdu_marshal(vs->pdu, vs->offset, "d", vs->total);
     vs->offset += vs->count;
-    err = vs->offset;
+    vs->err = vs->offset;
 
 out:
-    complete_pdu(s, vs->pdu, err);
+    complete_pdu(vs->s, vs->pdu, vs->err);
     qemu_free(vs);
 }
 
@@ -2188,7 +2290,6 @@  static void v9fs_read(V9fsState *s, V9fsPDU *pdu)
 {
     int32_t fid;
     V9fsReadState *vs;
-    ssize_t err = 0;
 
     vs = qemu_malloc(sizeof(*vs));
     vs->pdu = pdu;
@@ -2196,12 +2297,13 @@  static void v9fs_read(V9fsState *s, V9fsPDU *pdu)
     vs->total = 0;
     vs->len = 0;
     vs->count = 0;
+    vs->s = s;
 
     pdu_unmarshal(vs->pdu, vs->offset, "dqd", &fid, &vs->off, &vs->count);
 
     vs->fidp = lookup_fid(s, fid);
     if (vs->fidp == NULL) {
-        err = -EINVAL;
+        vs->err = -EINVAL;
         goto out;
     }
 
@@ -2209,32 +2311,30 @@  static void v9fs_read(V9fsState *s, V9fsPDU *pdu)
         vs->max_count = vs->count;
         vs->count = 0;
         if (vs->off == 0) {
-            v9fs_do_rewinddir(s, vs->fidp->fs.dir);
+            v9fs_do_async_posix(&vs->work, v9fs_read_do_rewinddir,
+                                &vs->post_fn, v9fs_read_post_rewinddir);
+            return;
         }
-        v9fs_read_post_rewinddir(s, vs, err);
+        v9fs_read_post_rewinddir(vs);
         return;
     } else if (vs->fidp->fid_type == P9_FID_FILE) {
         vs->sg = vs->iov;
         pdu_marshal(vs->pdu, vs->offset + 4, "v", vs->sg, &vs->cnt);
         vs->sg = cap_sg(vs->sg, vs->count, &vs->cnt);
         if (vs->total <= vs->count) {
-            vs->len = v9fs_do_preadv(s, vs->fidp->fs.fd, vs->sg, vs->cnt,
-                                    vs->off);
-            if (vs->len > 0) {
-                vs->off += vs->len;
-            }
-            err = vs->len;
-            v9fs_read_post_preadv(s, vs, err);
+            vs->err = vs->len;
+            v9fs_do_async_posix(&vs->work, v9fs_read_do_preadv,
+                                &vs->post_fn, v9fs_read_post_preadv);
         }
         return;
     } else if (vs->fidp->fid_type == P9_FID_XATTR) {
         v9fs_xattr_read(s, vs);
         return;
     } else {
-        err = -EINVAL;
+        vs->err = -EINVAL;
     }
 out:
-    complete_pdu(s, pdu, err);
+    complete_pdu(s, pdu, vs->err);
     qemu_free(vs);
 }
 
diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h
index 74d7b68..fcea434 100644
--- a/hw/virtio-9p.h
+++ b/hw/virtio-9p.h
@@ -325,6 +325,11 @@  typedef struct V9fsReadState {
     int32_t len;
     int32_t cnt;
     int32_t max_count;
+    V9fsState *s;
+    int err;
+    int v9fs_errno;
+    ThreadletWork work;
+    void (*post_fn)(void *arg);
 } V9fsReadState;
 
 typedef struct V9fsWriteState {