Commit 262fc47a authored by Juergen Gross's avatar Juergen Gross Committed by Boris Ostrovsky
Browse files

xen/balloon: don't use PV mode extra memory for zone device allocations 



When running as a Xen PV guest use the extra memory (memory which isn't
allocated for the guest at boot time) only for ballooning purposes and
not for zone device allocations. This will remove some code without any
lack of functionality.

While at it move some code to get rid of another #ifdef.

Remove a comment which is stale since some time now.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220407093857.1485-1-jgross@suse.com


Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent de2ae403

drivers/xen/balloon.c

+23 −31
Original line number Diff line number Diff line
@@ -689,11 +689,19 @@ void xen_free_ballooned_pages(unsigned int nr_pages, struct page **pages) 
}

EXPORT_SYMBOL(xen_free_ballooned_pages);



#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)

static void __init balloon_add_region(unsigned long start_pfn,

				      unsigned long pages)

static void __init balloon_add_regions(void)

{

#if defined(CONFIG_XEN_PV)

	unsigned long start_pfn, pages;

	unsigned long pfn, extra_pfn_end;

	unsigned int i;



	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {

		pages = xen_extra_mem[i].n_pfns;

		if (!pages)

			continue;



		start_pfn = xen_extra_mem[i].start_pfn;



		/*

		 * If the amount of usable memory has been limited (e.g., with
@@ -702,16 +710,13 @@ static void __init balloon_add_region(unsigned long start_pfn, 
		 */

		extra_pfn_end = min(max_pfn, start_pfn + pages);



	for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) {

		/* totalram_pages and totalhigh_pages do not

		   include the boot-time balloon extension, so

		   don't subtract from it. */

		for (pfn = start_pfn; pfn < extra_pfn_end; pfn++)

			balloon_append(pfn_to_page(pfn));

	}



		balloon_stats.total_pages += extra_pfn_end - start_pfn;

	}

#endif

}



static int __init balloon_init(void)

{
@@ -745,20 +750,7 @@ static int __init balloon_init(void) 
	register_sysctl_table(xen_root);

#endif



#if defined(CONFIG_XEN_PV) && !defined(CONFIG_XEN_UNPOPULATED_ALLOC)

	{

		int i;



		/*

		 * Initialize the balloon with pages from the extra memory

		 * regions (see arch/x86/xen/setup.c).

		 */

		for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++)

			if (xen_extra_mem[i].n_pfns)

				balloon_add_region(xen_extra_mem[i].start_pfn,

						   xen_extra_mem[i].n_pfns);

	}

#endif

	balloon_add_regions();



	task = kthread_run(balloon_thread, NULL, "xen-balloon");

	if (IS_ERR(task)) {

drivers/xen/unpopulated-alloc.c

+0 −33
Original line number Diff line number Diff line
@@ -230,39 +230,6 @@ void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) 
}

EXPORT_SYMBOL(xen_free_unpopulated_pages);



#ifdef CONFIG_XEN_PV

static int __init init(void)

{

	unsigned int i;



	if (!xen_domain())

		return -ENODEV;



	if (!xen_pv_domain())

		return 0;



	/*

	 * Initialize with pages from the extra memory regions (see

	 * arch/x86/xen/setup.c).

	 */

	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {

		unsigned int j;



		for (j = 0; j < xen_extra_mem[i].n_pfns; j++) {

			struct page *pg =

				pfn_to_page(xen_extra_mem[i].start_pfn + j);



			pg->zone_device_data = page_list;

			page_list = pg;

			list_count++;

		}

	}



	return 0;

}

subsys_initcall(init);

#endif



static int __init unpopulated_init(void)

{

	int ret;