@@ -523,7 +523,7 @@ out:
int domain_set_outstanding_pages(struct domain *d, unsigned long pages)
{
int ret = -ENOMEM;
- unsigned long claim, avail_pages;
+ unsigned long avail_pages;
/*
* take the domain's page_alloc_lock, else all d->tot_page adjustments
@@ -549,28 +549,21 @@ int domain_set_outstanding_pages(struct domain *d, unsigned long pages)
goto out;
}
- /* disallow a claim not exceeding domain_tot_pages() or above max_pages */
- if ( (pages <= domain_tot_pages(d)) || (pages > d->max_pages) )
+ /* Don't claim past max_pages */
+ if ( (domain_tot_pages(d) + pages) > d->max_pages )
{
ret = -EINVAL;
goto out;
}
/* how much memory is available? */
- avail_pages = total_avail_pages;
+ avail_pages = total_avail_pages - outstanding_claims;
- avail_pages -= outstanding_claims;
-
- /*
- * Note, if domain has already allocated memory before making a claim
- * then the claim must take domain_tot_pages() into account
- */
- claim = pages - domain_tot_pages(d);
- if ( claim > avail_pages )
+ if ( pages > avail_pages )
goto out;
/* yay, claim fits in available memory, stake the claim, success! */
- d->outstanding_pages = claim;
+ d->outstanding_pages = pages;
outstanding_claims += d->outstanding_pages;
ret = 0;
With a single global count for the claims it's easy to substract domain_tot_pages() from the claim so the number given in the hypercall is the real reservation of the domain. This is the current behaviour. However, a later patch introduces exact-node claims and those interact very poorly with such a scheme. Since accounting domain_tot_pages() in one case but not the other seems strictly worse than not accounting them at all (which is at least consistent), this patch stops substracting tot_pages from the claim and instead checks that claimed memory + allocated memory don't exceed max_mem. Arguably it's also clearer for the caller to align the amount of claimed memory with that of the requested claim. Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com> --- xen/common/page_alloc.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-)