[pve-devel] [PATCH v2 qemu 2/2] add optional buffer size to QEMUFile
Wolfgang Bumiller
w.bumiller at proxmox.com
Mon May 4 14:35:01 CEST 2020
and use 4M for our savevm-async buffer size
Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
---
Changes to v1: add missing call to free() in qemu_fclose.
...add-optional-buffer-size-to-QEMUFile.patch | 183 ++++++++++++++++++
debian/patches/series | 1 +
2 files changed, 184 insertions(+)
create mode 100644 debian/patches/pve/0044-add-optional-buffer-size-to-QEMUFile.patch
diff --git a/debian/patches/pve/0044-add-optional-buffer-size-to-QEMUFile.patch b/debian/patches/pve/0044-add-optional-buffer-size-to-QEMUFile.patch
new file mode 100644
index 0000000..daad1f5
--- /dev/null
+++ b/debian/patches/pve/0044-add-optional-buffer-size-to-QEMUFile.patch
@@ -0,0 +1,183 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Wolfgang Bumiller <w.bumiller at proxmox.com>
+Date: Mon, 4 May 2020 11:05:08 +0200
+Subject: [PATCH] add optional buffer size to QEMUFile
+
+So we can use a 4M buffer for savevm-async which should
+increase performance storing the state onto ceph.
+
+Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
+---
+ migration/qemu-file.c | 36 ++++++++++++++++++++++++------------
+ migration/qemu-file.h | 1 +
+ savevm-async.c | 4 ++--
+ 3 files changed, 27 insertions(+), 14 deletions(-)
+
+diff --git a/migration/qemu-file.c b/migration/qemu-file.c
+index 1c3a358a14..7362e51c71 100644
+--- a/migration/qemu-file.c
++++ b/migration/qemu-file.c
+@@ -30,7 +30,7 @@
+ #include "trace.h"
+ #include "qapi/error.h"
+
+-#define IO_BUF_SIZE 32768
++#define DEFAULT_IO_BUF_SIZE 32768
+ #define MAX_IOV_SIZE MIN(IOV_MAX, 64)
+
+ struct QEMUFile {
+@@ -45,7 +45,8 @@ struct QEMUFile {
+ when reading */
+ int buf_index;
+ int buf_size; /* 0 when writing */
+- uint8_t buf[IO_BUF_SIZE];
++ size_t buf_allocated_size;
++ uint8_t *buf;
+
+ DECLARE_BITMAP(may_free, MAX_IOV_SIZE);
+ struct iovec iov[MAX_IOV_SIZE];
+@@ -101,7 +102,7 @@ bool qemu_file_mode_is_not_valid(const char *mode)
+ return false;
+ }
+
+-QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)
++QEMUFile *qemu_fopen_ops_sized(void *opaque, const QEMUFileOps *ops, size_t buffer_size)
+ {
+ QEMUFile *f;
+
+@@ -109,9 +110,17 @@ QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)
+
+ f->opaque = opaque;
+ f->ops = ops;
++ f->buf_allocated_size = buffer_size;
++ f->buf = malloc(buffer_size);
++
+ return f;
+ }
+
++QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)
++{
++ return qemu_fopen_ops_sized(opaque, ops, DEFAULT_IO_BUF_SIZE);
++}
++
+
+ void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks)
+ {
+@@ -346,7 +355,7 @@ static ssize_t qemu_fill_buffer(QEMUFile *f)
+ }
+
+ len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,
+- IO_BUF_SIZE - pending, &local_error);
++ f->buf_allocated_size - pending, &local_error);
+ if (len > 0) {
+ f->buf_size += len;
+ f->pos += len;
+@@ -386,6 +395,9 @@ int qemu_fclose(QEMUFile *f)
+ ret = ret2;
+ }
+ }
++
++ free(f->buf);
++
+ /* If any error was spotted before closing, we should report it
+ * instead of the close() return value.
+ */
+@@ -435,7 +447,7 @@ static void add_buf_to_iovec(QEMUFile *f, size_t len)
+ {
+ if (!add_to_iovec(f, f->buf + f->buf_index, len, false)) {
+ f->buf_index += len;
+- if (f->buf_index == IO_BUF_SIZE) {
++ if (f->buf_index == f->buf_allocated_size) {
+ qemu_fflush(f);
+ }
+ }
+@@ -461,7 +473,7 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
+ }
+
+ while (size > 0) {
+- l = IO_BUF_SIZE - f->buf_index;
++ l = f->buf_allocated_size - f->buf_index;
+ if (l > size) {
+ l = size;
+ }
+@@ -508,8 +520,8 @@ size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset)
+ size_t index;
+
+ assert(!qemu_file_is_writable(f));
+- assert(offset < IO_BUF_SIZE);
+- assert(size <= IO_BUF_SIZE - offset);
++ assert(offset < f->buf_allocated_size);
++ assert(size <= f->buf_allocated_size - offset);
+
+ /* The 1st byte to read from */
+ index = f->buf_index + offset;
+@@ -559,7 +571,7 @@ size_t qemu_get_buffer(QEMUFile *f, uint8_t *buf, size_t size)
+ size_t res;
+ uint8_t *src;
+
+- res = qemu_peek_buffer(f, &src, MIN(pending, IO_BUF_SIZE), 0);
++ res = qemu_peek_buffer(f, &src, MIN(pending, f->buf_allocated_size), 0);
+ if (res == 0) {
+ return done;
+ }
+@@ -593,7 +605,7 @@ size_t qemu_get_buffer(QEMUFile *f, uint8_t *buf, size_t size)
+ */
+ size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size)
+ {
+- if (size < IO_BUF_SIZE) {
++ if (size < f->buf_allocated_size) {
+ size_t res;
+ uint8_t *src;
+
+@@ -618,7 +630,7 @@ int qemu_peek_byte(QEMUFile *f, int offset)
+ int index = f->buf_index + offset;
+
+ assert(!qemu_file_is_writable(f));
+- assert(offset < IO_BUF_SIZE);
++ assert(offset < f->buf_allocated_size);
+
+ if (index >= f->buf_size) {
+ qemu_fill_buffer(f);
+@@ -770,7 +782,7 @@ static int qemu_compress_data(z_stream *stream, uint8_t *dest, size_t dest_len,
+ ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
+ const uint8_t *p, size_t size)
+ {
+- ssize_t blen = IO_BUF_SIZE - f->buf_index - sizeof(int32_t);
++ ssize_t blen = f->buf_allocated_size - f->buf_index - sizeof(int32_t);
+
+ if (blen < compressBound(size)) {
+ return -1;
+diff --git a/migration/qemu-file.h b/migration/qemu-file.h
+index a9b6d6ccb7..8752d27c74 100644
+--- a/migration/qemu-file.h
++++ b/migration/qemu-file.h
+@@ -120,6 +120,7 @@ typedef struct QEMUFileHooks {
+ } QEMUFileHooks;
+
+ QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
++QEMUFile *qemu_fopen_ops_sized(void *opaque, const QEMUFileOps *ops, size_t buffer_size);
+ void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
+ int qemu_get_fd(QEMUFile *f);
+ int qemu_fclose(QEMUFile *f);
+diff --git a/savevm-async.c b/savevm-async.c
+index af865b9a0a..c3fe741c38 100644
+--- a/savevm-async.c
++++ b/savevm-async.c
+@@ -338,7 +338,7 @@ void qmp_savevm_start(bool has_statefile, const char *statefile, Error **errp)
+ goto restart;
+ }
+
+- snap_state.file = qemu_fopen_ops(&snap_state, &block_file_ops);
++ snap_state.file = qemu_fopen_ops_sized(&snap_state, &block_file_ops, 4 * 1024 * 1024);
+
+ if (!snap_state.file) {
+ error_set(errp, ERROR_CLASS_GENERIC_ERROR, "failed to open '%s'", statefile);
+@@ -454,7 +454,7 @@ int load_snapshot_from_blockdev(const char *filename, Error **errp)
+ blk_op_block_all(be, blocker);
+
+ /* restore the VM state */
+- f = qemu_fopen_ops(be, &loadstate_file_ops);
++ f = qemu_fopen_ops_sized(be, &loadstate_file_ops, 4 * 1024 * 1024);
+ if (!f) {
+ error_setg(errp, "Could not open VM state file");
+ goto the_end;
diff --git a/debian/patches/series b/debian/patches/series
index 34ca660..670b744 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -41,3 +41,4 @@ pve/0040-PVE-savevm-async-set-up-migration-state.patch
pve/0041-PVE-Backup-avoid-use-QemuRecMutex-inside-coroutines.patch
pve/0042-PVE-Backup-use-QemuMutex-instead-of-QemuRecMutex.patch
pve/0043-move-savevm-async-back-into-a-coroutine.patch
+pve/0044-add-optional-buffer-size-to-QEMUFile.patch
--
2.20.1
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