Re: [Qemu-devel] [PATCH v2 13/16] postcopy: Allow hugepages

[Laurent Vivier]

On 06/02/2017 18:33, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> Allow huge pages in postcopy.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> Reviewed-by: Juan Quintela <address@hidden>
> ---
>  migration/postcopy-ram.c | 25 +------------------------
>  1 file changed, 1 insertion(+), 24 deletions(-)
> 
> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> index 03cbd6e..6b30b43 100644
> --- a/migration/postcopy-ram.c
> +++ b/migration/postcopy-ram.c
> @@ -85,24 +85,6 @@ static bool ufd_version_check(int ufd)
>  }
>  
>  /*
> - * Check for things that postcopy won't support; returns 0 if the block
> - * is fine.
> - */
> -static int check_range(const char *block_name, void *host_addr,
> -                      ram_addr_t offset, ram_addr_t length, void *opaque)
> -{
> -    RAMBlock *rb = qemu_ram_block_by_name(block_name);
> -
> -    if (qemu_ram_pagesize(rb) > getpagesize()) {
> -        error_report("Postcopy doesn't support large page sizes yet (%s)",
> -                     block_name);
> -        return -E2BIG;
> -    }
> -
> -    return 0;
> -}
> -
> -/*
>   * Note: This has the side effect of munlock'ing all of RAM, that's
>   * normally fine since if the postcopy succeeds it gets turned back on at the
>   * end.
> @@ -122,12 +104,6 @@ bool postcopy_ram_supported_by_host(void)
>          goto out;
>      }
>  
> -    /* Check for anything about the RAMBlocks we don't support */
> -    if (qemu_ram_foreach_block(check_range, NULL)) {
> -        /* check_range will have printed its own error */
> -        goto out;
> -    }
> -
>      ufd = syscall(__NR_userfaultfd, O_CLOEXEC);
>      if (ufd == -1) {
>          error_report("%s: userfaultfd not available: %s", __func__,
> @@ -139,6 +115,7 @@ bool postcopy_ram_supported_by_host(void)
>      if (!ufd_version_check(ufd)) {
>          goto out;
>      }
> +    /* TODO: Only allow huge pages if the kernel supports it */
>  
>      /*
>       * userfault and mlock don't go together; we'll put it back later if
> 
Reviewed-by: Laurent Vivier <address@hidden>