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Re: [Qemu-devel] [RFC 10/12] Add qemu_put_buffer_no_copy
From: |
Orit Wasserman |
Subject: |
Re: [Qemu-devel] [RFC 10/12] Add qemu_put_buffer_no_copy |
Date: |
Mon, 25 Mar 2013 10:11:45 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 |
On 03/23/2013 06:27 PM, Michael R. Hines wrote:
> Can you add a "flag" or something to indicate that the iov pointer belongs to
> RAM and not to device state?
>
> That way, I could re-use this code for RDMA - if I see this flag, I will know
> to send to RDMA.....
This function is called only for ram pages so no need for flag.
Orit
>
> - Michael
>
>
> On 03/21/2013 05:09 AM, Orit Wasserman wrote:
>> This allow us to add a buffer to the iovec to send without copying it
>> into the static buffer.
>>
>> Signed-off-by: Orit Wasserman <address@hidden>
>> ---
>> include/migration/qemu-file.h | 5 +++++
>> savevm.c | 42
>> ++++++++++++++++++++++++------------------
>> 2 files changed, 29 insertions(+), 18 deletions(-)
>>
>> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
>> index 8d3da9b..5168be2 100644
>> --- a/include/migration/qemu-file.h
>> +++ b/include/migration/qemu-file.h
>> @@ -75,6 +75,11 @@ int qemu_fclose(QEMUFile *f);
>> int64_t qemu_ftell(QEMUFile *f);
>> void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size);
>> void qemu_put_byte(QEMUFile *f, int v);
>> +/*
>> + * put_buffer without copying the buffer.
>> + * The buffer should be available till it is sent.
>> + */
>> +void qemu_put_buffer_no_copy(QEMUFile *f, const uint8_t *buf, int size);
>>
>> static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v)
>> {
>> diff --git a/savevm.c b/savevm.c
>> index 40d96f4..32a506e 100644
>> --- a/savevm.c
>> +++ b/savevm.c
>> @@ -629,6 +629,22 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf,
>> int size)
>> {
>> int l;
>>
>> + while (size > 0) {
>> + l = IO_BUF_SIZE - f->buf_index;
>> + if (l > size) {
>> + l = size;
>> + }
>> + memcpy(f->buf + f->buf_index, buf, l);
>> + f->buf_index += l;
>> + f->is_write = 1;
>> + qemu_put_buffer_no_copy(f, f->buf + (f->buf_index - l), l);
>> + buf += l;
>> + size -= l;
>> + }
>> +}
>> +
>> +void qemu_put_buffer_no_copy(QEMUFile *f, const uint8_t *buf, int size)
>> +{
>> if (f->last_error) {
>> return;
>> }
>> @@ -639,24 +655,14 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf,
>> int size)
>> abort();
>> }
>>
>> - while (size > 0) {
>> - l = IO_BUF_SIZE - f->buf_index;
>> - if (l > size)
>> - l = size;
>> - memcpy(f->buf + f->buf_index, buf, l);
>> - f->iov[f->iovcnt].iov_base = f->buf + f->buf_index;
>> - f->iov[f->iovcnt++].iov_len = l;
>> - f->is_write = 1;
>> - f->buf_index += l;
>> - f->bytes_xfer += l;
>> - buf += l;
>> - size -= l;
>> - if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> - qemu_fflush(f);
>> - if (qemu_file_get_error(f)) {
>> - break;
>> - }
>> - }
>> + f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
>> + f->iov[f->iovcnt++].iov_len = size;
>> +
>> + f->is_write = 1;
>> + f->bytes_xfer += size;
>> +
>> + if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> + qemu_fflush(f);
>> }
>> }
>>
>
- Re: [Qemu-devel] [RFC 07/12] Store the data to send also in iovec, (continued)
[Qemu-devel] [RFC 08/12] Use writev ops instead of put_buffer ops, Orit Wasserman, 2013/03/21
[Qemu-devel] [RFC 09/12] More optimized qemu_put_be64/32/16, Orit Wasserman, 2013/03/21
[Qemu-devel] [RFC 10/12] Add qemu_put_buffer_no_copy, Orit Wasserman, 2013/03/21
[Qemu-devel] [RFC 11/12] Use qemu_put_buffer_no_copy for guest memory pages, Orit Wasserman, 2013/03/21
[Qemu-devel] [RFC 12/12] Bye Bye put_buffer, Orit Wasserman, 2013/03/21
Re: [Qemu-devel] [RFC 00/12] Migration: Remove copying of guest ram pages, Paolo Bonzini, 2013/03/21
Re: [Qemu-devel] [RFC 00/12] Migration: Remove copying of guest ram pages, Michael S. Tsirkin, 2013/03/21