On 05/21/2018 07:35 PM, Boris Ostrovsky wrote:
On 05/21/2018 01:40 AM, Oleksandr Andrushchenko wrote:
On 05/19/2018 01:04 AM, Boris Ostrovsky wrote:
On 05/17/2018 04:26 AM, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
A commit message would be useful.
Sure, v1 will have it
Signed-off-by: Oleksandr Andrushchenko
<oleksandr_andrushchenko@xxxxxxxx>
for (i = 0; i < nr_pages; i++) {
- page = alloc_page(gfp);
- if (page == NULL) {
- nr_pages = i;
- state = BP_EAGAIN;
- break;
+ if (ext_pages) {
+ page = ext_pages[i];
+ } else {
+ page = alloc_page(gfp);
+ if (page == NULL) {
+ nr_pages = i;
+ state = BP_EAGAIN;
+ break;
+ }
}
scrub_page(page);
list_add(&page->lru, &pages);
@@ -529,7 +565,7 @@ static enum bp_state
decrease_reservation(unsigned long nr_pages, gfp_t gfp)
i = 0;
list_for_each_entry_safe(page, tmp, &pages, lru) {
/* XENMEM_decrease_reservation requires a GFN */
- frame_list[i++] = xen_page_to_gfn(page);
+ frames[i++] = xen_page_to_gfn(page);
#ifdef CONFIG_XEN_HAVE_PVMMU
/*
@@ -552,18 +588,22 @@ static enum bp_state
decrease_reservation(unsigned long nr_pages, gfp_t gfp)
#endif
list_del(&page->lru);
- balloon_append(page);
+ if (!ext_pages)
+ balloon_append(page);
So what you are proposing is not really ballooning. You are just
piggybacking on existing interfaces, aren't you?
Sort of. Basically I need to {increase|decrease}_reservation, not
actually
allocating ballooned pages.
Do you think I can simply EXPORT_SYMBOL for
{increase|decrease}_reservation?
Any other suggestion?
I am actually wondering how much of that code you end up reusing. You
pretty much create new code paths in both routines and common code ends
up being essentially the hypercall.
Well, I hoped that it would be easier to maintain if I modify existing code
to support both use-cases, but I am also ok to create new routines if this
seems to be reasonable - please let me know
So the question is --- would it make
sense to do all of this separately from the balloon driver?
This can be done, but which driver will host this code then? If we move from
the balloon driver, then this could go to either gntdev or grant-table.
What's your preference?
-boris
Thank you,
Oleksandr
