From: Juan Quintela <quintela@redhat.com>
To: qemu-devel@nongnu.org
Cc: Thomas Huth <thuth@redhat.com>, Peter Xu <peterx@redhat.com>,
Leonardo Bras <leobras@redhat.com>,
Juan Quintela <quintela@redhat.com>,
Laurent Vivier <lvivier@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Lukas Straub <lukasstraub2@web.de>
Subject: [PULL 06/13] ram.c: Do not call save_page_header() from compress threads
Date: Mon, 8 May 2023 20:52:02 +0200 [thread overview]
Message-ID: <20230508185209.68604-7-quintela@redhat.com> (raw)
In-Reply-To: <20230508185209.68604-1-quintela@redhat.com>
From: Lukas Straub <lukasstraub2@web.de>
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>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
migration/ram.c | 44 +++++++++++++++++++++++++++++++++++---------
1 file changed, 35 insertions(+), 9 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 4e14e3bb94..c52602b70d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1465,17 +1465,13 @@ 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
@@ -1515,9 +1511,40 @@ static inline void compress_reset_result(CompressParam *param)
param->offset = 0;
}
+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)
{
- MigrationState *ms = migrate_get_current();
int idx, len, thread_count;
if (!save_page_use_compression(rs)) {
@@ -1537,7 +1564,7 @@ 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);
/*
@@ -1563,7 +1590,6 @@ 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);
@@ -1573,7 +1599,7 @@ 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);
--
2.40.0
next prev parent reply other threads:[~2023-05-08 18:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-08 18:51 [PULL 00/13] Compression code patches Juan Quintela
2023-05-08 18:51 ` [PULL 01/13] qtest/migration-test.c: Add tests with compress enabled Juan Quintela
2023-05-08 18:51 ` [PULL 02/13] qtest/migration-test.c: Add postcopy " Juan Quintela
2023-05-08 18:51 ` [PULL 03/13] ram.c: Let the compress threads return a CompressResult enum Juan Quintela
2023-05-08 18:52 ` [PULL 04/13] ram.c: Dont change param->block in the compress thread Juan Quintela
2023-05-08 18:52 ` [PULL 05/13] ram.c: Reset result after sending queued data Juan Quintela
2023-05-08 18:52 ` Juan Quintela [this message]
2023-05-08 18:52 ` [PULL 07/13] ram.c: Call update_compress_thread_counts from compress_send_queued_data Juan Quintela
2023-05-08 18:52 ` [PULL 08/13] ram.c: Remove last ram.c dependency from the core compress code Juan Quintela
2023-05-08 18:52 ` [PULL 09/13] ram.c: Move core compression code into its own file Juan Quintela
2023-05-08 18:52 ` [PULL 10/13] ram.c: Move core decompression " Juan Quintela
2023-05-08 18:52 ` [PULL 11/13] ram compress: Assert that the file buffer matches the result Juan Quintela
2023-05-08 18:52 ` [PULL 12/13] ram-compress.c: Make target independent Juan Quintela
2023-05-08 18:52 ` [PULL 13/13] migration: Initialize and cleanup decompression in migration.c Juan Quintela
2023-05-09 6:34 ` [PULL 00/13] Compression code patches Richard Henderson
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