svn commit: r368523 - head/sys/vm

[Hans Petter Selasky]

On 12/10/20 9:44 PM, Bryan Drewery wrote:
> Author: bdrewery
> Date: Thu Dec 10 20:44:29 2020
> New Revision: 368523
> URL: https://svnweb.freebsd.org/changeset/base/368523
> 
> Log:
>    contig allocs: Don't retry forever on M_WAITOK.
>    
>    This restores behavior from before domain iterators were added in
>    r327895 and r327896.
>    
>    The vm_domainset_iter_policy() will do a vm_wait_doms() and then
>    restart its iterator when M_WAITOK is set.  It will also force
>    the containing loop to have M_NOWAIT.  So we get an unbounded
>    retry loop rather than the intended bounded retries that
>    kmem_alloc_contig_pages() already handles.
>    
>    This also restores M_WAITOK to the vmem_alloc() call in
>    kmem_alloc_attr_domain() and kmem_alloc_contig_domain().
>    
>    Reviewed by:	markj, kib
>    MFC after:	2 weeks
>    Sponsored by:	Dell EMC
>    Differential Revision:	https://reviews.freebsd.org/D27507
> 
> Modified:
>    head/sys/vm/vm_kern.c
> 
> Modified: head/sys/vm/vm_kern.c
> ==============================================================================
> --- head/sys/vm/vm_kern.c	Thu Dec 10 20:44:05 2020	(r368522)
> +++ head/sys/vm/vm_kern.c	Thu Dec 10 20:44:29 2020	(r368523)
> @@ -264,9 +264,15 @@ kmem_alloc_attr_domainset(struct domainset *ds, vm_siz
>   {
>   	struct vm_domainset_iter di;
>   	vm_offset_t addr;
> -	int domain;
> +	int domain, iflags;
>   
> -	vm_domainset_iter_policy_init(&di, ds, &domain, &flags);
> +	/*
> +	 * Do not allow the domainset iterator to override wait flags.  The
> +	 * contiguous memory allocator defines special semantics for M_WAITOK
> +	 * that do not match the iterator's implementation.
> +	 */
> +	iflags = (flags & ~M_WAITOK) | M_NOWAIT;
> +	vm_domainset_iter_policy_init(&di, ds, &domain, &iflags);
>   	do {
>   		addr = kmem_alloc_attr_domain(domain, size, flags, low, high,
>   		    memattr);
> @@ -346,9 +352,15 @@ kmem_alloc_contig_domainset(struct domainset *ds, vm_s
>   {
>   	struct vm_domainset_iter di;
>   	vm_offset_t addr;
> -	int domain;
> +	int domain, iflags;
>   
> -	vm_domainset_iter_policy_init(&di, ds, &domain, &flags);
> +	/*
> +	 * Do not allow the domainset iterator to override wait flags.  The
> +	 * contiguous memory allocator defines special semantics for M_WAITOK
> +	 * that do not match the iterator's implementation.
> +	 */
> +	iflags = (flags & ~M_WAITOK) | M_NOWAIT;
> +	vm_domainset_iter_policy_init(&di, ds, &domain, &iflags);
>   	do {
>   		addr = kmem_alloc_contig_domain(domain, size, flags, low, high,
>   		    alignment, boundary, memattr);
> 

Hi,

Should "iflags" also be passed to kmem_alloc_contig_domain() !?

I'm seeing the following panic:

panic("vm_wait in early boot")
vm_wait_domain()
kmem_alloc_contig_pages()
kmem_alloc_contig_domainset()
kmem_alloc_contig()
contigmalloc()
x86bios_alloc()
vesa_configure()
vesa_mod_event()
vesa_module_register_init()
mi_startup()

--HPS