Unverified Commit 34fbe42d authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!14331 mm: avoid unconditional one-tick sleep when swapcache_prepare fails 

Merge Pull Request from: @ci-robot 
 
PR sync from: Jinjiang Tu <tujinjiang@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/GKFAF7SJZMMQAOHLLYYJ47LJWNEBQ3W3/ 
 
https://gitee.com/openeuler/kernel/issues/IB7294 
 
Link:https://gitee.com/openeuler/kernel/pulls/14331
parents 3a0ee774 9f5858aa

mm/memory.c

+13 −2
Original line number Diff line number Diff line
@@ -3397,6 +3397,8 @@ void unmap_mapping_range(struct address_space *mapping, 
}

EXPORT_SYMBOL(unmap_mapping_range);



static DECLARE_WAIT_QUEUE_HEAD(swapcache_wq);



/*

 * We enter with non-exclusive mmap_lock (to exclude vma changes,

 * but allow concurrent faults), and pte mapped but not yet locked.
@@ -3408,6 +3410,7 @@ EXPORT_SYMBOL(unmap_mapping_range); 
vm_fault_t do_swap_page(struct vm_fault *vmf)

{

	struct vm_area_struct *vma = vmf->vma;

	DECLARE_WAITQUEUE(wait, current);

	struct page *page = NULL, *swapcache;

	struct swap_info_struct *si = NULL;

	bool need_clear_cache = false;
@@ -3475,7 +3478,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) 
			 */

			if (swapcache_prepare(entry)) {

				/* Relax a bit to prevent rapid repeated page faults */

				add_wait_queue(&swapcache_wq, &wait);

				schedule_timeout_uninterruptible(1);

				remove_wait_queue(&swapcache_wq, &wait);

				goto out;

			}

			need_clear_cache = true;
@@ -3650,8 +3655,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) 
	pte_unmap_unlock(vmf->pte, vmf->ptl);

out:

	/* Clear the swap cache pin for direct swapin after PTL unlock */

	if (need_clear_cache)

	if (need_clear_cache) {

		swapcache_clear(si, entry);

		if (waitqueue_active(&swapcache_wq))

			wake_up(&swapcache_wq);

	}

	if (si)

		put_swap_device(si);

	return ret;
@@ -3665,8 +3673,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) 
		unlock_page(swapcache);

		put_page(swapcache);

	}

	if (need_clear_cache)

	if (need_clear_cache) {

		swapcache_clear(si, entry);

		if (waitqueue_active(&swapcache_wq))

			wake_up(&swapcache_wq);

	}

	if (si)

		put_swap_device(si);

	return ret;