[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 1/4] migration: set f->is_write and flush in add
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 1/4] migration: set f->is_write and flush in add_to_iovec |
Date: |
Tue, 09 Apr 2013 13:39:34 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 |
Il 09/04/2013 13:32, Juan Quintela ha scritto:
> Paolo Bonzini <address@hidden> wrote:
>> Signed-off-by: Paolo Bonzini <address@hidden>
>> ---
>> savevm.c | 25 +++++++++----------------
>> 1 file changed, 9 insertions(+), 16 deletions(-)
>>
>> diff --git a/savevm.c b/savevm.c
>> index b1d8988..c952c41 100644
>> --- a/savevm.c
>> +++ b/savevm.c
>> @@ -631,6 +631,11 @@ static void add_to_iovec(QEMUFile *f, const uint8_t
>> *buf, int size)
>> f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
>> f->iov[f->iovcnt++].iov_len = size;
>> }
>> +
>> + f->is_write = 1;
>> + if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> + qemu_fflush(f);
>> + }
>> }
>>
>> void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size)
>> @@ -645,14 +650,8 @@ void qemu_put_buffer_async(QEMUFile *f, const uint8_t
>> *buf, int size)
>> abort();
>> }
>>
>> - add_to_iovec(f, buf, size);
>> -
>> - f->is_write = 1;
>> f->bytes_xfer += size;
>> -
>> - if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> - qemu_fflush(f);
>> - }
>> + add_to_iovec(f, buf, size);
>> }
>>
>> void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
>> @@ -674,7 +673,6 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf,
>> int size)
>> if (l > size)
>> l = size;
>> memcpy(f->buf + f->buf_index, buf, l);
>> - f->is_write = 1;
>> f->buf_index += l;
>
> we increase buf_index
>
>> qemu_put_buffer_async(f, f->buf + (f->buf_index - l), l);
>
> and we call add_to_iovec() here inside. Notice the torture to get the
> old buf_index value.
>
>> if (qemu_file_get_error(f)) {
>> @@ -697,15 +695,10 @@ void qemu_put_byte(QEMUFile *f, int v)
>> abort();
>> }
>>
>> - f->buf[f->buf_index++] = v;
>> - f->is_write = 1;
>> + f->buf[f->buf_index] = v;
>> f->bytes_xfer++;
>> -
>> - add_to_iovec(f, f->buf + (f->buf_index - 1), 1);
>> -
>> - if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> - qemu_fflush(f);
>> - }
>> + add_to_iovec(f, f->buf + f->buf_index, 1);
>> + f->buf_index++;
>
> And here, we call add_to_iovec() and then increase buf_index
>
> Is there any good reason for not being consistent?
The reason is that I didn't want to switch
qemu_put_buffer_async->add_to_iovec in this patch. I do it in the next one.
> Once there, I think that moving the handling of buf_index to inside
> add_to_iovec() looks like a good idea?
add_to_iovec() is not called always with something from f->buf. But it
is a good idea to move this handling of buf_index:
if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
out of add_to_iovec. I do that in patch 4.
Paolo
[Qemu-devel] [PATCH 2/4] migration: use a single I/O operation when writev_buffer is not defined, Paolo Bonzini, 2013/04/08
[Qemu-devel] [PATCH 4/4] migration: simplify writev vs. non-writev logic, Paolo Bonzini, 2013/04/08