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Re: [Qemu-devel] [PATCH v8 41/54] postcopy_ram.c: place_page and helpers
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [PATCH v8 41/54] postcopy_ram.c: place_page and helpers |
Date: |
Wed, 28 Oct 2015 11:28:26 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
"Dr. David Alan Gilbert (git)" <address@hidden> wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> postcopy_place_page (etc) provide a way for postcopy to place a page
> into guests memory atomically (using the copy ioctl on the ufd).
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> Reviewed-by: Amit Shah <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
> +int postcopy_place_page_zero(MigrationIncomingState *mis, void *host)
> +{
> + 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)) {
> + int e = errno;
> + error_report("%s: %s zero host: %p",
> + __func__, strerror(e), host);
> +
> + return -e;
> + }
> +
> + trace_postcopy_place_page_zero(host);
> + return 0;
> +}
Would this be faster than normal precopy way of just copying a zero page?
- Re: [Qemu-devel] [PATCH v8 38/54] Page request: Add MIG_RP_MSG_REQ_PAGES reverse command, (continued)
- [Qemu-devel] [PATCH v8 39/54] Page request: Process incoming page request, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 40/54] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 42/54] Postcopy: Use helpers to map pages during migration, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 43/54] Don't sync dirty bitmaps in postcopy, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 41/54] postcopy_ram.c: place_page and helpers, Dr. David Alan Gilbert (git), 2015/10/01
- Re: [Qemu-devel] [PATCH v8 41/54] postcopy_ram.c: place_page and helpers,
Juan Quintela <=
- [Qemu-devel] [PATCH v8 44/54] Don't iterate on precopy-only devices during postcopy, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 45/54] Host page!=target page: Cleanup bitmaps, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 46/54] postcopy: Check order of received target pages, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 47/54] Round up RAMBlock sizes to host page sizes, Dr. David Alan Gilbert (git), 2015/10/01
- [Qemu-devel] [PATCH v8 48/54] Postcopy; Handle userfault requests, Dr. David Alan Gilbert (git), 2015/10/01