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Re: [Patch v2 5/6] migration/postcopy: enable random order target page a
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Patch v2 5/6] migration/postcopy: enable random order target page arrival |
Date: |
Thu, 7 Nov 2019 14:30:25 +0000 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
* Wei Yang (address@hidden) wrote:
> After using number of target page received to track one host page, we
> could have the capability to handle random order target page arrival in
> one host page.
>
> This is a preparation for enabling compress during postcopy.
>
> Signed-off-by: Wei Yang <address@hidden>
Yep, that's better
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> v2:
> * use uintptr_t to calculate place_dest
> * check target pages belongs to the same host page
> ---
> migration/ram.c | 18 ++++++++++--------
> 1 file changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index b5759793a9..666ad69284 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -4015,7 +4015,7 @@ static int ram_load_postcopy(QEMUFile *f)
> MigrationIncomingState *mis = migration_incoming_get_current();
> /* Temporary page that is later 'placed' */
> void *postcopy_host_page = mis->postcopy_tmp_page;
> - void *last_host = NULL;
> + void *this_host = NULL;
> bool all_zero = false;
> int target_pages = 0;
>
> @@ -4062,24 +4062,26 @@ static int ram_load_postcopy(QEMUFile *f)
> * that's moved into place later.
> * The migration protocol uses, possibly smaller, target-pages
> * however the source ensures it always sends all the components
> - * of a host page in order.
> + * of a host page in one chunk.
> */
> page_buffer = postcopy_host_page +
> ((uintptr_t)host & (block->page_size - 1));
> /* If all TP are zero then we can optimise the place */
> if (target_pages == 1) {
> all_zero = true;
> + this_host = (void *)QEMU_ALIGN_DOWN((uintptr_t)host,
> + block->page_size);
> } else {
> /* not the 1st TP within the HP */
> - if (host != (last_host + TARGET_PAGE_SIZE)) {
> - error_report("Non-sequential target page %p/%p",
> - host, last_host);
> + if (QEMU_ALIGN_DOWN((uintptr_t)host, block->page_size) !=
> + (uintptr_t)this_host) {
> + error_report("Non-same host page %p/%p",
> + host, this_host);
> ret = -EINVAL;
> break;
> }
> }
>
> -
> /*
> * If it's the last part of a host page then we place the host
> * page
> @@ -4090,7 +4092,6 @@ static int ram_load_postcopy(QEMUFile *f)
> }
> place_source = postcopy_host_page;
> }
> - last_host = host;
>
> switch (flags & ~RAM_SAVE_FLAG_CONTINUE) {
> case RAM_SAVE_FLAG_ZERO:
> @@ -4143,7 +4144,8 @@ static int ram_load_postcopy(QEMUFile *f)
>
> if (!ret && place_needed) {
> /* This gets called at the last target page in the host page */
> - void *place_dest = host + TARGET_PAGE_SIZE - block->page_size;
> + void *place_dest = (void *)QEMU_ALIGN_DOWN((uintptr_t)host,
> + block->page_size);
>
> if (all_zero) {
> ret = postcopy_place_page_zero(mis, place_dest,
> --
> 2.17.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Patch v2 0/6] migration/postcopy: enable compress during postcopy, Wei Yang, 2019/11/07
- [Patch v2 1/6] migration/postcopy: reduce memset when it is zero page and matches_target_page_size, Wei Yang, 2019/11/07
- [Patch v2 3/6] migration/postcopy: count target page number to decide the place_needed, Wei Yang, 2019/11/07
- [Patch v2 4/6] migration/postcopy: set all_zero to true on the first target page, Wei Yang, 2019/11/07
- [Patch v2 2/6] migration/postcopy: wait for decompress thread in precopy, Wei Yang, 2019/11/07
- [Patch v2 5/6] migration/postcopy: enable random order target page arrival, Wei Yang, 2019/11/07
- Re: [Patch v2 5/6] migration/postcopy: enable random order target page arrival,
Dr. David Alan Gilbert <=
- [Patch v2 6/6] migration/postcopy: enable compress during postcopy, Wei Yang, 2019/11/07