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[Qemu-devel] [PATCH v2 8/9] migration: refine the decompression code
From: |
Liang Li |
Subject: |
[Qemu-devel] [PATCH v2 8/9] migration: refine the decompression code |
Date: |
Thu, 5 May 2016 15:32:58 +0800 |
The current code for multi-thread decompression is not clear,
especially in the aspect of using lock. Refine the code
to make it clear.
Signed-off-by: Liang Li <address@hidden>
---
migration/ram.c | 50 +++++++++++++++++++++++++-------------------------
1 file changed, 25 insertions(+), 25 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index f44f833..51de958 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -262,7 +262,6 @@ struct CompressParam {
typedef struct CompressParam CompressParam;
struct DecompressParam {
- bool start;
bool done;
bool quit;
QemuMutex mutex;
@@ -830,15 +829,6 @@ static int do_compress_ram_page(QEMUFile *f, RAMBlock
*block,
return bytes_sent;
}
-static inline void start_decompression(DecompressParam *param)
-{
- param->done = false;
- qemu_mutex_lock(¶m->mutex);
- param->start = true;
- qemu_cond_signal(¶m->cond);
- qemu_mutex_unlock(¶m->mutex);
-}
-
static uint64_t bytes_transferred;
static void flush_compressed_data(QEMUFile *f)
@@ -2195,30 +2185,37 @@ static void *do_data_decompress(void *opaque)
{
DecompressParam *param = opaque;
unsigned long pagesize;
+ uint8_t *des;
+ int len;
+ qemu_mutex_lock(¶m->mutex);
while (!param->quit) {
- qemu_mutex_lock(¶m->mutex);
- while (!param->start && !param->quit) {
- qemu_cond_wait(¶m->cond, ¶m->mutex);
- }
- if (!param->quit) {
+ if (param->des) {
+ des = param->des;
+ len = param->len;
+ param->des = 0;
+ qemu_mutex_unlock(¶m->mutex);
+
pagesize = TARGET_PAGE_SIZE;
/* uncompress() will return failed in some case, especially
* when the page is dirted when doing the compression, it's
* not a problem because the dirty page will be retransferred
* and uncompress() won't break the data in other pages.
*/
- uncompress((Bytef *)param->des, &pagesize,
- (const Bytef *)param->compbuf, param->len);
- }
- param->start = false;
- qemu_mutex_unlock(¶m->mutex);
+ uncompress((Bytef *)des, &pagesize,
+ (const Bytef *)param->compbuf, len);
- qemu_mutex_lock(&decomp_done_lock);
- param->done = true;
- qemu_cond_signal(&decomp_done_cond);
- qemu_mutex_unlock(&decomp_done_lock);
+ qemu_mutex_lock(&decomp_done_lock);
+ param->done = true;
+ qemu_cond_signal(&decomp_done_cond);
+ qemu_mutex_unlock(&decomp_done_lock);
+
+ qemu_mutex_lock(¶m->mutex);
+ } else {
+ qemu_cond_wait(¶m->cond, ¶m->mutex);
+ }
}
+ qemu_mutex_unlock(¶m->mutex);
return NULL;
}
@@ -2295,10 +2292,13 @@ static void decompress_data_with_multi_threads(QEMUFile
*f,
while (true) {
for (idx = 0; idx < thread_count; idx++) {
if (decomp_param[idx].done) {
+ decomp_param[idx].done = false;
+ qemu_mutex_lock(&decomp_param[idx].mutex);
qemu_get_buffer(f, decomp_param[idx].compbuf, len);
decomp_param[idx].des = host;
decomp_param[idx].len = len;
- start_decompression(&decomp_param[idx]);
+ qemu_cond_signal(&decomp_param[idx].cond);
+ qemu_mutex_unlock(&decomp_param[idx].mutex);
break;
}
}
--
1.9.1
- [Qemu-devel] [PATCH v2 0/9] live migration bug fix and refine, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 1/9] migration: Fix multi-thread compression bug, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 2/9] migration: Fix a potential issue, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 3/9] migration: remove useless code, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 6/9] migration: protect the quit flag by lock, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 7/9] migration: refine the compression code, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 4/9] qemu-file: Fix qemu_put_compression_data flaw, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 8/9] migration: refine the decompression code,
Liang Li <=
- [Qemu-devel] [PATCH v2 5/9] migration: refine ram_save_compressed_page, Liang Li, 2016/05/05
- [Qemu-devel] [PATCH v2 9/9] migration: code clean up, Liang Li, 2016/05/05
- Re: [Qemu-devel] [PATCH v2 0/9] live migration bug fix and refine, Amit Shah, 2016/05/23