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[PATCH 04/14] ram.c: Do not call save_page_header() from compress thread
From: |
Lukas Straub |
Subject: |
[PATCH 04/14] ram.c: Do not call save_page_header() from compress threads |
Date: |
Sun, 2 Apr 2023 17:56:14 +0000 |
save_page_header() accesses several global variables, so calling it
from multiple threads is pretty ugly.
Instead, call save_page_header() before writing out the compressed
data from the compress buffer to the migration stream.
This also makes the core compress code more independend from ram.c.
Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
migration/ram.c | 44 +++++++++++++++++++++++++++++++++++---------
1 file changed, 35 insertions(+), 9 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index bef6292ef7..7ab008145b 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1476,17 +1476,13 @@ static CompressResult do_compress_ram_page(QEMUFile *f,
z_stream *stream,
RAMBlock *block, ram_addr_t offset,
uint8_t *source_buf)
{
- RAMState *rs = ram_state;
- PageSearchStatus *pss = &rs->pss[RAM_CHANNEL_PRECOPY];
uint8_t *p = block->host + offset;
int ret;
- if (save_zero_page_to_file(pss, f, block, offset)) {
+ if (buffer_is_zero(p, TARGET_PAGE_SIZE)) {
return RES_ZEROPAGE;
}
- save_page_header(pss, f, block, offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
-
/*
* copy it to a internal buffer to avoid it being modified by VM
* so that we can catch up the error during compression and
@@ -1526,9 +1522,40 @@ static inline void compress_reset_result(CompressParam
*param)
param->offset = 0;
}
-static void flush_compressed_data(RAMState *rs)
+static int send_queued_data(CompressParam *param)
{
+ PageSearchStatus *pss = &ram_state->pss[RAM_CHANNEL_PRECOPY];
MigrationState *ms = migrate_get_current();
+ QEMUFile *file = ms->to_dst_file;
+ int len = 0;
+
+ RAMBlock *block = param->block;
+ ram_addr_t offset = param->offset;
+
+ if (param->result == RES_NONE) {
+ return 0;
+ }
+
+ assert(block == pss->last_sent_block);
+
+ if (param->result == RES_ZEROPAGE) {
+ len += save_page_header(pss, file, block, offset | RAM_SAVE_FLAG_ZERO);
+ qemu_put_byte(file, 0);
+ len += 1;
+ ram_release_page(block->idstr, offset);
+ } else if (param->result == RES_COMPRESS) {
+ len += save_page_header(pss, file, block,
+ offset | RAM_SAVE_FLAG_COMPRESS_PAGE);
+ len += qemu_put_qemu_file(file, param->file);
+ } else {
+ abort();
+ }
+
+ return len;
+}
+
+static void flush_compressed_data(RAMState *rs)
+{
int idx, len, thread_count;
if (!save_page_use_compression(rs)) {
@@ -1548,7 +1575,7 @@ static void flush_compressed_data(RAMState *rs)
qemu_mutex_lock(&comp_param[idx].mutex);
if (!comp_param[idx].quit) {
CompressParam *param = &comp_param[idx];
- len = qemu_put_qemu_file(ms->to_dst_file, param->file);
+ len = send_queued_data(param);
compress_reset_result(param);
/*
@@ -1574,7 +1601,6 @@ static int compress_page_with_multi_thread(RAMBlock
*block, ram_addr_t offset)
{
int idx, thread_count, bytes_xmit = -1, pages = -1;
bool wait = migrate_compress_wait_thread();
- MigrationState *ms = migrate_get_current();
thread_count = migrate_compress_threads();
qemu_mutex_lock(&comp_done_lock);
@@ -1584,7 +1610,7 @@ retry:
CompressParam *param = &comp_param[idx];
qemu_mutex_lock(¶m->mutex);
param->done = false;
- bytes_xmit = qemu_put_qemu_file(ms->to_dst_file, param->file);
+ bytes_xmit = send_queued_data(param);
compress_reset_result(param);
set_compress_params(param, block, offset);
--
2.30.2
pgpOAz6Y0jdEQ.pgp
Description: OpenPGP digital signature
- [PATCH 00/14] migration/ram.c: Refactor compress code, Lukas Straub, 2023/04/02
- [PATCH 03/14] ram.c: Reset result after sending queued data, Lukas Straub, 2023/04/02
- [PATCH 04/14] ram.c: Do not call save_page_header() from compress threads,
Lukas Straub <=
- [PATCH 01/14] ram.c: Let the compress threads return a CompressResult enum, Lukas Straub, 2023/04/02
- [PATCH 02/14] ram.c: Dont change param->block in the compress thread, Lukas Straub, 2023/04/02
- [PATCH 05/14] ram.c: Call update_compress_thread_counts from compress_send_queued_data, Lukas Straub, 2023/04/02
- [PATCH 06/14] ram.c: Remove last ram.c dependency from the core compress code, Lukas Straub, 2023/04/02
- [PATCH 07/14] ram.c: Introduce whitespace (squash with next patch), Lukas Straub, 2023/04/02
- [PATCH 08/14] ram.c: Move core compression code into its own file, Lukas Straub, 2023/04/02
- [PATCH 09/14] ram.c: Remove whitespace (squash with previous patch), Lukas Straub, 2023/04/02
- [PATCH 10/14] ram.c: Move core decompression code into its own file, Lukas Straub, 2023/04/02