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virtio-mem: factor out handling of fake-offline pages in memory notifier

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Let's factor out the core pieces and place the implementation next to
virtio_mem_fake_offline(). We'll reuse this functionality soon.

Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20201112133815.13332-10-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
David Hildenbrand 2020-11-12 14:37:55 +01:00 committed by Michael S. Tsirkin
parent 89c486c47f
commit 7a34c77dab
1 changed files with 50 additions and 23 deletions
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73
drivers/virtio/virtio_mem.c
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@ -160,6 +160,10 @@ static DEFINE_MUTEX(virtio_mem_mutex);
static LIST_HEAD(virtio_mem_devices);
static void virtio_mem_online_page_cb(struct page *page, unsigned int order);
static void virtio_mem_fake_offline_going_offline(unsigned long pfn,
unsigned long nr_pages);
static void virtio_mem_fake_offline_cancel_offline(unsigned long pfn,
unsigned long nr_pages);
/*
* Register a virtio-mem device so it will be considered for the online_page
@ -586,27 +590,15 @@ static void virtio_mem_notify_going_offline(struct virtio_mem *vm,
unsigned long mb_id)
{
const unsigned long nr_pages = PFN_DOWN(vm->subblock_size);
struct page *page;
unsigned long pfn;
int sb_id, i;
int sb_id;
for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
continue;
/*
* Drop our reference to the pages so the memory can get
* offlined and add the unplugged pages to the managed
* page counters (so offlining code can correctly subtract
* them again).
*/
pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
sb_id * vm->subblock_size);
adjust_managed_page_count(pfn_to_page(pfn), nr_pages);
for (i = 0; i < nr_pages; i++) {
page = pfn_to_page(pfn + i);
if (WARN_ON(!page_ref_dec_and_test(page)))
dump_page(page, "unplugged page referenced");
}
virtio_mem_fake_offline_going_offline(pfn, nr_pages);
}
}
@ -615,21 +607,14 @@ static void virtio_mem_notify_cancel_offline(struct virtio_mem *vm,
{
const unsigned long nr_pages = PFN_DOWN(vm->subblock_size);
unsigned long pfn;
int sb_id, i;
int sb_id;
for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) {
if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1))
continue;
/*
* Get the reference we dropped when going offline and
* subtract the unplugged pages from the managed page
* counters.
*/
pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +
sb_id * vm->subblock_size);
adjust_managed_page_count(pfn_to_page(pfn), -nr_pages);
for (i = 0; i < nr_pages; i++)
page_ref_inc(pfn_to_page(pfn + i));
virtio_mem_fake_offline_cancel_offline(pfn, nr_pages);
}
}
@ -814,6 +799,48 @@ static int virtio_mem_fake_offline(unsigned long pfn, unsigned long nr_pages)
return 0;
}
/*
* Handle fake-offline pages when memory is going offline - such that the
* pages can be skipped by mm-core when offlining.
*/
static void virtio_mem_fake_offline_going_offline(unsigned long pfn,
unsigned long nr_pages)
{
struct page *page;
unsigned long i;
/*
* Drop our reference to the pages so the memory can get offlined
* and add the unplugged pages to the managed page counters (so
* offlining code can correctly subtract them again).
*/
adjust_managed_page_count(pfn_to_page(pfn), nr_pages);
/* Drop our reference to the pages so the memory can get offlined. */
for (i = 0; i < nr_pages; i++) {
page = pfn_to_page(pfn + i);
if (WARN_ON(!page_ref_dec_and_test(page)))
dump_page(page, "fake-offline page referenced");
}
}
/*
* Handle fake-offline pages when memory offlining is canceled - to undo
* what we did in virtio_mem_fake_offline_going_offline().
*/
static void virtio_mem_fake_offline_cancel_offline(unsigned long pfn,
unsigned long nr_pages)
{
unsigned long i;
/*
* Get the reference we dropped when going offline and subtract the
* unplugged pages from the managed page counters.
*/
adjust_managed_page_count(pfn_to_page(pfn), -nr_pages);
for (i = 0; i < nr_pages; i++)
page_ref_inc(pfn_to_page(pfn + i));
}
static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
{
const unsigned long addr = page_to_phys(page);