96a5f8d770
block: dataplane for virtio, potentially large performance improvment migration: threaded live migration usb-tablet: usb 2.0 support, significantly lowering CPU usage usb: improved support for pass-through of USB serial devices virtio-net: added support supports multiqueue operation
71 lines
2.8 KiB
Diff
71 lines
2.8 KiB
Diff
From f6239f570a57ba6069ce1033b696365bdfed1b47 Mon Sep 17 00:00:00 2001
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From: Alon Levy <alevy@redhat.com>
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Date: Tue, 22 Mar 2011 12:28:00 +0200
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Subject: [PATCH] spice-qemu-char.c: remove intermediate buffer
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BZ: 672191
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upstream: not submitted (explained below)
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virtio-serial's buffer is valid when it calls us, and we don't
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access it otherwise: vmc_read is only called in response to wakeup,
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or else we set datalen=0 and throttle. Then vmc_read is called back,
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we return 0 (not accessing the buffer) and set the timer to unthrottle.
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Also make datalen int and not ssize_t (to fit spice_chr_write signature).
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This relied on the previous patch that introduces throttling, which
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can't go upstream right now as explained in that patch.
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Signed-off-by: Cole Robinson <crobinso@redhat.com>
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---
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spice-qemu-char.c | 18 ++++++------------
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1 file changed, 6 insertions(+), 12 deletions(-)
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diff --git a/spice-qemu-char.c b/spice-qemu-char.c
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index 75bb125..5065240 100644
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--- a/spice-qemu-char.c
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+++ b/spice-qemu-char.c
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@@ -23,9 +23,8 @@ typedef struct SpiceCharDriver {
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SpiceCharDeviceInstance sin;
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char *subtype;
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bool active;
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- uint8_t *buffer;
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- uint8_t *datapos;
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- ssize_t bufsize, datalen;
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+ const uint8_t *datapos;
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+ int datalen;
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uint32_t debug;
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QEMUTimer *unblock_timer;
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QLIST_ENTRY(SpiceCharDriver) next;
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@@ -73,7 +72,7 @@ static int vmc_read(SpiceCharDeviceInstance *sin, uint8_t *buf, int len)
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SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
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int bytes = MIN(len, scd->datalen);
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- dprintf(scd, 2, "%s: %p %d/%d/%zd\n", __func__, scd->datapos, len, bytes, scd->datalen);
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+ dprintf(scd, 2, "%s: %p %d/%d/%d\n", __func__, scd->datapos, len, bytes, scd->datalen);
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if (bytes > 0) {
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memcpy(buf, scd->datapos, bytes);
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scd->datapos += bytes;
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@@ -189,18 +188,13 @@ static int spice_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
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dprintf(s, 2, "%s: %d\n", __func__, len);
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vmc_register_interface(s);
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assert(s->datalen == 0);
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- if (s->bufsize < len) {
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- s->bufsize = len;
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- s->buffer = g_realloc(s->buffer, s->bufsize);
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- }
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- memcpy(s->buffer, buf, len);
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- s->datapos = s->buffer;
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+ s->datapos = buf;
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s->datalen = len;
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spice_server_char_device_wakeup(&s->sin);
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read_bytes = len - s->datalen;
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if (read_bytes != len) {
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- dprintf(s, 1, "%s: throttling: %d < %d (%zd)\n", __func__,
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- read_bytes, len, s->bufsize);
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+ dprintf(s, 1, "%s: throttling: %d < %d\n", __func__,
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+ read_bytes, len);
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s->chr->write_blocked = true;
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/* We'll get passed in the unconsumed data with the next call */
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s->datalen = 0;
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