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Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page |
Date: |
Wed, 26 Jul 2017 09:49:21 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Thu, Jul 20, 2017 at 09:52:34AM +0300, Alexey Perevalov wrote:
> This patch adds ability to track down already received
> pages, it's necessary for calculation vCPU block time in
> postcopy migration feature, maybe for restore after
> postcopy migration failure.
> Also it's necessary to solve shared memory issue in
> postcopy livemigration. Information about received pages
> will be transferred to the software virtual bridge
> (e.g. OVS-VSWITCHD), to avoid fallocate (unmap) for
> already received pages. fallocate syscall is required for
> remmaped shared memory, due to remmaping itself blocks
> ioctl(UFFDIO_COPY, ioctl in this case will end with EEXIT
> error (struct page is exists after remmap).
>
> Bitmap is placed into RAMBlock as another postcopy/precopy
> related bitmaps.
>
> Reviewed-by: Peter Xu <address@hidden>
> Signed-off-by: Alexey Perevalov <address@hidden>
> ---
[...]
> static int qemu_ufd_copy_ioctl(int userfault_fd, void *host_addr,
> - void *from_addr, uint64_t pagesize)
> + void *from_addr, uint64_t pagesize, RAMBlock
> *rb)
> {
> + int ret;
> 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);
> + ret = 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);
> + ret = ioctl(userfault_fd, UFFDIO_ZEROPAGE, &zero_struct);
> + }
> + if (!ret) {
> + ramblock_recv_bitmap_set(host_addr, rb);
Wait...
Now we are using 4k-page/bit bitmap, do we need to take care of the
huge pages here? Looks like we are only setting the first bit of it
if it is a huge page?
--
Peter Xu
- [Qemu-devel] [PATCH v8 0/3] Add bitmap for received pages in postcopy migration, Alexey Perevalov, 2017/07/20
- Message not available
- Message not available
- [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/20
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page,
Peter Xu <=
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/26
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Peter Xu, 2017/07/26
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/26
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Peter Xu, 2017/07/26
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/27
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Peter Xu, 2017/07/28
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/28
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Peter Xu, 2017/07/28
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/28
- Re: [Qemu-devel] [PATCH v8 3/3] migration: add bitmap for received page, Alexey Perevalov, 2017/07/28