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Re: [Qemu-devel] [PATCH 04/14] buffered_file: Move from using a timer to
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 04/14] buffered_file: Move from using a timer to use a thread |
Date: |
Fri, 21 Sep 2012 17:29:58 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120911 Thunderbird/15.0.1 |
Il 21/09/2012 16:08, Juan Quintela ha scritto:
> We still protect everything except the wait with the iothread lock.
> But we moved from a timer to a thread. Steps one by one.
>
> We also need to detect when we have finished with a variable "complete".
>
> Signed-off-by: Juan Quintela <address@hidden>
> ---
> buffered_file.c | 58
> +++++++++++++++++++++++++++++++++++----------------------
> 1 file changed, 36 insertions(+), 22 deletions(-)
>
> diff --git a/buffered_file.c b/buffered_file.c
> index 318d0f0..61985a9 100644
> --- a/buffered_file.c
> +++ b/buffered_file.c
> @@ -18,6 +18,7 @@
> #include "qemu-timer.h"
> #include "qemu-char.h"
> #include "buffered_file.h"
> +#include "qemu-thread.h"
>
> //#define DEBUG_BUFFERED_FILE
>
> @@ -31,7 +32,8 @@ typedef struct QEMUFileBuffered
> uint8_t *buffer;
> size_t buffer_size;
> size_t buffer_capacity;
> - QEMUTimer *timer;
> + QemuThread thread;
> + bool complete;
> } QEMUFileBuffered;
>
> #ifdef DEBUG_BUFFERED_FILE
> @@ -159,11 +161,8 @@ static int buffered_close(void *opaque)
> if (ret >= 0) {
> ret = ret2;
> }
> - qemu_del_timer(s->timer);
> - qemu_free_timer(s->timer);
> - g_free(s->buffer);
> - g_free(s);
> -
> + ret = migrate_fd_close(s->migration_state);
> + s->complete = true;
> return ret;
> }
>
> @@ -214,23 +213,38 @@ static int64_t buffered_get_rate_limit(void *opaque)
> return s->xfer_limit;
> }
>
> -static void buffered_rate_tick(void *opaque)
> +/* 10ms xfer_limit is the limit that we should write each 10ms */
> +#define BUFFER_DELAY 100
> +
> +static void *buffered_file_thread(void *opaque)
> {
> QEMUFileBuffered *s = opaque;
> + int64_t expire_time = qemu_get_clock_ms(rt_clock) + BUFFER_DELAY;
>
> - if (qemu_file_get_error(s->file)) {
> - buffered_close(s);
> - return;
> - }
> -
> - qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100);
> -
> - if (s->freeze_output)
> - return;
> -
> - s->bytes_xfer = 0;
> + while (true) {
> + int64_t current_time = qemu_get_clock_ms(rt_clock);
>
> - buffered_put_buffer(s, NULL, 0, 0);
> + if (s->complete) {
> + break;
> + }
> + if (s->freeze_output) {
> + continue;
> + }
> + if (current_time >= expire_time) {
> + s->bytes_xfer = 0;
> + expire_time = current_time + BUFFER_DELAY;
> + }
> + if (s->bytes_xfer >= s->xfer_limit) {
> + /* usleep expects microseconds */
> + usleep((expire_time - current_time)*1000);
usleep is broken under IIRC Solaris (it uses signals and conflicts with
qemu-timer.c). Please use g_usleep instead.
Bonus points for converting other users (hw/xenfb.c, qemu-ga.c,
tests/test-iov.c).
> + }
> + qemu_mutex_lock_iothread();
> + buffered_put_buffer(s, NULL, 0, 0);
> + qemu_mutex_unlock_iothread();
> + }
> + g_free(s->buffer);
> + g_free(s);
I think freeing "s" here is incorrect. Instead, you should "join" the
thread after setting s->complete = true, and move the g_free(s) to
buffered_close.
> + return NULL;
> }
>
> QEMUFile *qemu_fopen_ops_buffered(MigrationState *migration_state)
> @@ -241,15 +255,15 @@ QEMUFile *qemu_fopen_ops_buffered(MigrationState
> *migration_state)
>
> s->migration_state = migration_state;
> s->xfer_limit = migration_state->bandwidth_limit / 10;
> + s->complete = false;
>
> s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
> buffered_close, buffered_rate_limit,
> buffered_set_rate_limit,
> buffered_get_rate_limit);
>
> - s->timer = qemu_new_timer_ms(rt_clock, buffered_rate_tick, s);
> -
> - qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100);
> + qemu_thread_create(&s->thread, buffered_file_thread, s,
> + QEMU_THREAD_DETACHED);
So this needs to become QEMU_THREAD_JOINABLE.
>
> return s->file;
> }
>
Paolo
- [Qemu-devel] [RFC 00/14] Migration thread, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 01/14] split MRU ram list, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 03/14] protect the ramlist with a separate mutex, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 02/14] add a version number to ram_list, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 04/14] buffered_file: Move from using a timer to use a thread, Juan Quintela, 2012/09/21
- Re: [Qemu-devel] [PATCH 04/14] buffered_file: Move from using a timer to use a thread,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 05/14] migration: make qemu_fopen_ops_buffered() return void, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 09/14] migration: take finer locking, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 08/14] migration: remove unfreeze logic, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 13/14] savevm: New save live migration method: pending, Juan Quintela, 2012/09/21
- [Qemu-devel] [PATCH 14/14] migration: print times for end phase, Juan Quintela, 2012/09/21