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Re: [Qemu-devel] [RFC PATCH v4 08/28] QEMUSizedBuffer: Introduce two hel
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC PATCH v4 08/28] QEMUSizedBuffer: Introduce two help functions for qsb |
Date: |
Fri, 15 May 2015 12:56:34 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* zhanghailiang (address@hidden) wrote:
> Introduce two new QEMUSizedBuffer APIs which will be used by COLO to buffer
> VM state:
> One is qsb_put_buffer(), which put the content of a given QEMUSizedBuffer
> into QEMUFile, this is used to send buffered VM state to secondary.
> Another is qsb_fill_buffer(), read 'size' bytes of data from the file into
> qsb, this is used to get VM state from socket into a buffer.
>
> Signed-off-by: Yang Hongyang <address@hidden>
> Signed-off-by: zhanghailiang <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
(I could use these in my postcopy world)
Dave
> ---
> include/migration/qemu-file.h | 3 ++-
> migration/qemu-file-buf.c | 58
> +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 60 insertions(+), 1 deletion(-)
>
> diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
> index 745a850..09a0e2a 100644
> --- a/include/migration/qemu-file.h
> +++ b/include/migration/qemu-file.h
> @@ -140,7 +140,8 @@ ssize_t qsb_get_buffer(const QEMUSizedBuffer *, off_t
> start, size_t count,
> uint8_t *buf);
> ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t *buf,
> off_t pos, size_t count);
> -
> +void qsb_put_buffer(QEMUFile *f, QEMUSizedBuffer *qsb, int size);
> +int qsb_fill_buffer(QEMUSizedBuffer *qsb, QEMUFile *f, int size);
>
> /*
> * For use on files opened with qemu_bufopen
> diff --git a/migration/qemu-file-buf.c b/migration/qemu-file-buf.c
> index 16a51a1..686f417 100644
> --- a/migration/qemu-file-buf.c
> +++ b/migration/qemu-file-buf.c
> @@ -365,6 +365,64 @@ ssize_t qsb_write_at(QEMUSizedBuffer *qsb, const uint8_t
> *source,
> return count;
> }
>
> +
> +/**
> + * Put the content of a given QEMUSizedBuffer into QEMUFile.
> + *
> + * @f: A QEMUFile
> + * @qsb: A QEMUSizedBuffer
> + * @size: size of content to write
> + */
> +void qsb_put_buffer(QEMUFile *f, QEMUSizedBuffer *qsb, int size)
> +{
> + int i, l;
> +
> + for (i = 0; i < qsb->n_iov && size > 0; i++) {
> + l = MIN(qsb->iov[i].iov_len, size);
> + qemu_put_buffer(f, qsb->iov[i].iov_base, l);
> + size -= l;
> + }
> +}
> +
> +/*
> + * Read 'size' bytes of data from the file into qsb.
> + * always fill from pos 0 and used after qsb_create().
> + *
> + * It will return size bytes unless there was an error, in which case it will
> + * return as many as it managed to read (assuming blocking fd's which
> + * all current QEMUFile are)
> + */
> +int qsb_fill_buffer(QEMUSizedBuffer *qsb, QEMUFile *f, int size)
> +{
> + ssize_t rc = qsb_grow(qsb, size);
> + int pending = size, i;
> + qsb->used = 0;
> + uint8_t *buf = NULL;
> +
> + if (rc < 0) {
> + return rc;
> + }
> +
> + for (i = 0; i < qsb->n_iov && pending > 0; i++) {
> + int doneone = 0;
> + /* read until iov full */
> + while (doneone < qsb->iov[i].iov_len && pending > 0) {
> + int readone = 0;
> + buf = qsb->iov[i].iov_base;
> + readone = qemu_get_buffer(f, buf,
> + MIN(qsb->iov[i].iov_len - doneone, pending));
> + if (readone == 0) {
> + return qsb->used;
> + }
> + buf += readone;
> + doneone += readone;
> + pending -= readone;
> + qsb->used += readone;
> + }
> + }
> + return qsb->used;
> +}
> +
> typedef struct QEMUBuffer {
> QEMUSizedBuffer *qsb;
> QEMUFile *file;
> --
> 1.7.12.4
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [RFC PATCH v4 08/28] QEMUSizedBuffer: Introduce two help functions for qsb,
Dr. David Alan Gilbert <=