[Qemu-devel] [PATCH] scsi: switch from g_slice allocator to malloc

[Qemu-devel] [PATCH] scsi: switch from g_slice allocator to malloc

[Paolo Bonzini]

Simplify memory allocation by sticking with a single API.  GSlice
is not that fast anyway (tcmalloc/jemalloc are better).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/scsi-bus.c              |  4 ++--
 hw/scsi/virtio-scsi-dataplane.c | 10 +++++-----
 hw/scsi/virtio-scsi.c           | 12 +++++-------
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index ffac8f4..d373c1b 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -558,7 +558,7 @@ SCSIRequest *scsi_req_alloc(const SCSIReqOps *reqops, SCSIDevice *d,
     const int memset_off = offsetof(SCSIRequest, sense)
                            + sizeof(req->sense);
 
-    req = g_slice_alloc(reqops->size);
+    req = g_malloc(reqops->size);
     memset((uint8_t *)req + memset_off, 0, reqops->size - memset_off);
     req->refcount = 1;
     req->bus = bus;
@@ -1622,7 +1622,7 @@ void scsi_req_unref(SCSIRequest *req)
         }
         object_unref(OBJECT(req->dev));
         object_unref(OBJECT(qbus->parent));
-        g_slice_free1(req->ops->size, req);
+        g_free(req);
     }
 }
 
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index 5575648..1248fd9 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -57,7 +57,7 @@ static VirtIOSCSIVring *virtio_scsi_vring_init(VirtIOSCSI *s,
         return NULL;
     }
 
-    r = g_slice_new(VirtIOSCSIVring);
+    r = g_new(VirtIOSCSIVring, 1);
     r->host_notifier = *virtio_queue_get_host_notifier(vq);
     r->guest_notifier = *virtio_queue_get_guest_notifier(vq);
     aio_set_event_notifier(s->ctx, &r->host_notifier, handler);
@@ -73,7 +73,7 @@ static VirtIOSCSIVring *virtio_scsi_vring_init(VirtIOSCSI *s,
 fail_vring:
     aio_set_event_notifier(s->ctx, &r->host_notifier, NULL);
     k->set_host_notifier(qbus->parent, n, false);
-    g_slice_free(VirtIOSCSIVring, r);
+    g_free(r);
     return NULL;
 }
 
@@ -182,18 +182,18 @@ static void virtio_scsi_vring_teardown(VirtIOSCSI *s)
 
     if (s->ctrl_vring) {
         vring_teardown(&s->ctrl_vring->vring, vdev, 0);
-        g_slice_free(VirtIOSCSIVring, s->ctrl_vring);
+        g_free(s->ctrl_vring);
         s->ctrl_vring = NULL;
     }
     if (s->event_vring) {
         vring_teardown(&s->event_vring->vring, vdev, 1);
-        g_slice_free(VirtIOSCSIVring, s->event_vring);
+        g_free(s->event_vring);
         s->event_vring = NULL;
     }
     if (s->cmd_vrings) {
         for (i = 0; i < vs->conf.num_queues && s->cmd_vrings[i]; i++) {
             vring_teardown(&s->cmd_vrings[i]->vring, vdev, 2 + i);
-            g_slice_free(VirtIOSCSIVring, s->cmd_vrings[i]);
+            g_free(s->cmd_vrings[i]);
             s->cmd_vrings[i] = NULL;
         }
         free(s->cmd_vrings);
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 1c33f14..20885fb 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -47,7 +47,7 @@ VirtIOSCSIReq *virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq)
     const size_t zero_skip = offsetof(VirtIOSCSIReq, elem)
                              + sizeof(VirtQueueElement);
 
-    req = g_slice_alloc(sizeof(*req) + vs->cdb_size);
+    req = g_malloc(sizeof(*req) + vs->cdb_size);
     req->vq = vq;
     req->dev = s;
     qemu_sglist_init(&req->qsgl, DEVICE(s), 8, &address_space_memory);
@@ -58,11 +58,9 @@ VirtIOSCSIReq *virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq)
 
 void virtio_scsi_free_req(VirtIOSCSIReq *req)
 {
-    VirtIOSCSICommon *vs = (VirtIOSCSICommon *)req->dev;
-
     qemu_iovec_destroy(&req->resp_iov);
     qemu_sglist_destroy(&req->qsgl);
-    g_slice_free1(sizeof(*req) + vs->cdb_size, req);
+    g_free(req);
 }
 
 static void virtio_scsi_complete_req(VirtIOSCSIReq *req)
@@ -250,7 +248,7 @@ static void virtio_scsi_cancel_notify(Notifier *notifier, void *data)
     if (--n->tmf_req->remaining == 0) {
         virtio_scsi_complete_req(n->tmf_req);
     }
-    g_slice_free(VirtIOSCSICancelNotifier, n);
+    g_free(n);
 }
 
 /* Return 0 if the request is ready to be completed and return to guest;
@@ -301,7 +299,7 @@ static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
                 VirtIOSCSICancelNotifier *notifier;
 
                 req->remaining = 1;
-                notifier = g_slice_new(VirtIOSCSICancelNotifier);
+                notifier = g_new(VirtIOSCSICancelNotifier, 1);
                 notifier->tmf_req = req;
                 notifier->notifier.notify = virtio_scsi_cancel_notify;
                 scsi_req_cancel_async(r, &notifier->notifier);
@@ -350,7 +348,7 @@ static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req)
                     VirtIOSCSICancelNotifier *notifier;
 
                     req->remaining++;
-                    notifier = g_slice_new(VirtIOSCSICancelNotifier);
+                    notifier = g_new(VirtIOSCSICancelNotifier, 1);
                     notifier->notifier.notify = virtio_scsi_cancel_notify;
                     notifier->tmf_req = req;
                     scsi_req_cancel_async(r, &notifier->notifier);
-- 
2.5.0

Re: [Qemu-devel] [PATCH] scsi: switch from g_slice allocator to malloc

[Stefan Hajnoczi]

On Thu, Oct 01, 2015 at 01:04:40PM +0200, Paolo Bonzini wrote:
> Simplify memory allocation by sticking with a single API.  GSlice
> is not that fast anyway (tcmalloc/jemalloc are better).
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/scsi/scsi-bus.c              |  4 ++--
>  hw/scsi/virtio-scsi-dataplane.c | 10 +++++-----
>  hw/scsi/virtio-scsi.c           | 12 +++++-------
>  3 files changed, 12 insertions(+), 14 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>