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Re: [Qemu-devel] [PATCH v2 2/3] migration: introduce qemu_ufd_copy_ioctl
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 2/3] migration: introduce qemu_ufd_copy_ioctl helper |
Date: |
Fri, 16 Jun 2017 17:39:39 +0100 |
User-agent: |
Mutt/1.8.2 (2017-04-18) |
* Peter Xu (address@hidden) wrote:
> On Thu, Jun 15, 2017 at 07:36:14PM +0300, Alexey Perevalov wrote:
> > Just for placing auxilary operations inside helper,
> > auxilary operations like: track received pages,
> > notify about copying operation in futher patches.
> >
> > Signed-off-by: Alexey Perevalov <address@hidden>
> > ---
> > migration/postcopy-ram.c | 35 ++++++++++++++++++++++-------------
> > 1 file changed, 22 insertions(+), 13 deletions(-)
> >
> > diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> > index 743ca6c..38a429a 100644
> > --- a/migration/postcopy-ram.c
> > +++ b/migration/postcopy-ram.c
> > @@ -561,6 +561,26 @@ int postcopy_ram_enable_notify(MigrationIncomingState
> > *mis)
> > return 0;
> > }
> >
> > +static int qemu_ufd_copy_ioctl(int userfault_fd, void *host_addr,
> > + void *from_addr, uint64_t pagesize)
> > +{
> > + if (from_addr) {
> > + struct uffdio_copy copy_struct;
> > + copy_struct.dst = (uint64_t)(uintptr_t)host_addr;
> > + copy_struct.src = (uint64_t)(uintptr_t)from_addr;
> > + copy_struct.len = pagesize;
> > + copy_struct.mode = 0;
> > + return ioctl(userfault_fd, UFFDIO_COPY, ©_struct);
> > + } else {
> > + struct uffdio_zeropage zero_struct;
> > + zero_struct.range.start = (uint64_t)(uintptr_t)host_addr;
> > + zero_struct.range.len = pagesize;
> > + zero_struct.mode = 0;
> > + return ioctl(userfault_fd, UFFDIO_ZEROPAGE, &zero_struct);
> > + }
> > + return 0;
>
> Remove this line?
Yes, probably should; only minor.
> > +}
> > +
> > /*
> > * Place a host page (from) at (host) atomically
> > * returns 0 on success
> > @@ -568,20 +588,14 @@ int postcopy_ram_enable_notify(MigrationIncomingState
> > *mis)
> > int postcopy_place_page(MigrationIncomingState *mis, void *host, void
> > *from,
> > RAMBlock *rb)
> > {
> > - struct uffdio_copy copy_struct;
> > size_t pagesize = qemu_ram_pagesize(rb);
> >
> > - copy_struct.dst = (uint64_t)(uintptr_t)host;
> > - copy_struct.src = (uint64_t)(uintptr_t)from;
> > - copy_struct.len = pagesize;
> > - copy_struct.mode = 0;
> > -
> > /* copy also acks to the kernel waking the stalled thread up
> > * TODO: We can inhibit that ack and only do it if it was requested
> > * which would be slightly cheaper, but we'd have to be careful
> > * of the order of updating our page state.
> > */
> > - if (ioctl(mis->userfault_fd, UFFDIO_COPY, ©_struct)) {
> > + if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, from, pagesize)) {
>
> (hmm I know "from" won't be zero, but naturally if without the context
> I would doubt it. Shall we add an assert here? You call.)
Doesn't seem worth it.
> Besides:
>
> Reviewed-by: Peter Xu <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
>
> Thanks,
>
> > int e = errno;
> > error_report("%s: %s copy host: %p from: %p (size: %zd)",
> > __func__, strerror(e), host, from, pagesize);
> > @@ -605,12 +619,7 @@ int postcopy_place_page_zero(MigrationIncomingState
> > *mis, void *host,
> >
> > pagesize = qemu_ram_pagesize(rb);
> > if (pagesize == getpagesize()) {
> > - struct uffdio_zeropage zero_struct;
> > - zero_struct.range.start = (uint64_t)(uintptr_t)host;
> > - zero_struct.range.len = getpagesize();
> > - zero_struct.mode = 0;
> > -
> > - if (ioctl(mis->userfault_fd, UFFDIO_ZEROPAGE, &zero_struct)) {
> > + if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, 0,
> > getpagesize())) {
> > int e = errno;
> > error_report("%s: %s zero host: %p",
> > __func__, strerror(e), host);
> > --
> > 1.9.1
> >
>
> --
> Peter Xu
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] [PATCH v2 0/3] Add bitmap for received pages in postcopy migration, Alexey Perevalov, 2017/06/15
- Message not available
- Message not available
- Message not available
- Re: [Qemu-devel] [PATCH v2 3/3] migration: add bitmap for received page, Dr. David Alan Gilbert, 2017/06/16
- Re: [Qemu-devel] [PATCH v2 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/06/16
- Re: [Qemu-devel] [PATCH v2 3/3] migration: add bitmap for received page, Dr. David Alan Gilbert, 2017/06/16
- Re: [Qemu-devel] [PATCH v2 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/06/16