[Xen-devel] [PATCH v1 2/3] xen/balloon: Mark pages PG_offline in balloon_append()

[David Hildenbrand <david@xxxxxxxxxx>]

Let's move the __SetPageOffline() call which all callers perform into
balloon_append().

In bp_state decrease_reservation(), pages are now marked PG_offline a
little later than before, however, this should not matter for XEN.

Suggested-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
 drivers/xen/balloon.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 37443c5fda99..8c245e99bb06 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -158,6 +158,8 @@ static DECLARE_DELAYED_WORK(balloon_worker, 
balloon_process);
 /* balloon_append: add the given page to the balloon. */
 static void balloon_append(struct page *page)
 {
+       __SetPageOffline(page);
+
        /* Lowmem is re-populated first, so highmem pages go at list tail. */
        if (PageHighMem(page)) {
                list_add_tail(&page->lru, &ballooned_pages);
@@ -372,7 +374,6 @@ static void xen_online_page(struct page *page, unsigned int 
order)
        for (i = 0; i < size; i++) {
                p = pfn_to_page(start_pfn + i);
                __online_page_set_limits(p);
-               __SetPageOffline(p);
                balloon_append(p);
        }
        mutex_unlock(&balloon_mutex);
@@ -466,7 +467,6 @@ static enum bp_state decrease_reservation(unsigned long 
nr_pages, gfp_t gfp)
                        state = BP_EAGAIN;
                        break;
                }
-               __SetPageOffline(page);
                adjust_managed_page_count(page, -1);
                xenmem_reservation_scrub_page(page);
                list_add(&page->lru, &pages);
@@ -648,10 +648,8 @@ void free_xenballooned_pages(int nr_pages, struct page 
**pages)
        mutex_lock(&balloon_mutex);
 
        for (i = 0; i < nr_pages; i++) {
-               if (pages[i]) {
-                       __SetPageOffline(pages[i]);
+               if (pages[i])
                        balloon_append(pages[i]);
-               }
        }
 
        balloon_stats.target_unpopulated -= nr_pages;
@@ -669,7 +667,6 @@ static void __init balloon_add_region(unsigned long 
start_pfn,
                                      unsigned long pages)
 {
        unsigned long pfn, extra_pfn_end;
-       struct page *page;
 
        /*
         * If the amount of usable memory has been limited (e.g., with
@@ -679,12 +676,10 @@ 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++) {
-               page = pfn_to_page(pfn);
                /* totalram_pages and totalhigh_pages do not
                   include the boot-time balloon extension, so
                   don't subtract from it. */
-               __SetPageOffline(page);
-               balloon_append(page);
+               balloon_append(pfn_to_page(pfn));
        }
 
        balloon_stats.total_pages += extra_pfn_end - start_pfn;
-- 
2.21.0


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