1 files changed, 43 insertions, 15 deletions

diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index d175c0f1e2c8..99b3e9408aa0 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -91,18 +91,21 @@ void tlb_flush_rmaps(struct mmu_gather *tlb, struct vm_area_struct *vma)
 }
 #endif
 
-static void tlb_batch_pages_flush(struct mmu_gather *tlb)
-{
-	struct mmu_gather_batch *batch;
+/*
+ * We might end up freeing a lot of pages. Reschedule on a regular
+ * basis to avoid soft lockups in configurations without full
+ * preemption enabled. The magic number of 512 folios seems to work.
+ */
+#define MAX_NR_FOLIOS_PER_FREE		512
 
-	for (batch = &tlb->local; batch && batch->nr; batch = batch->next) {
-		struct encoded_page **pages = batch->encoded_pages;
+static void __tlb_batch_free_encoded_pages(struct mmu_gather_batch *batch)
+{
+	struct encoded_page **pages = batch->encoded_pages;
+	unsigned int nr, nr_pages;
 
-		while (batch->nr) {
-			/*
-			 * limit free batch count when PAGE_SIZE > 4K
-			 */
-			unsigned int nr = min(512U, batch->nr);
+	while (batch->nr) {
+		if (!page_poisoning_enabled_static() && !want_init_on_free()) {
+			nr = min(MAX_NR_FOLIOS_PER_FREE, batch->nr);
 
 			/*
 			 * Make sure we cover page + nr_pages, and don't leave
@@ -111,14 +114,39 @@ static void tlb_batch_pages_flush(struct mmu_gather *tlb)
 			if (unlikely(encoded_page_flags(pages[nr - 1]) &
 				     ENCODED_PAGE_BIT_NR_PAGES_NEXT))
 				nr++;
+		} else {
+			/*
+			 * With page poisoning and init_on_free, the time it
+			 * takes to free memory grows proportionally with the
+			 * actual memory size. Therefore, limit based on the
+			 * actual memory size and not the number of involved
+			 * folios.
+			 */
+			for (nr = 0, nr_pages = 0;
+			     nr < batch->nr && nr_pages < MAX_NR_FOLIOS_PER_FREE;
+			     nr++) {
+				if (unlikely(encoded_page_flags(pages[nr]) &
+					     ENCODED_PAGE_BIT_NR_PAGES_NEXT))
+					nr_pages += encoded_nr_pages(pages[++nr]);
+				else
+					nr_pages++;
+			}
+		}
 
-			free_pages_and_swap_cache(pages, nr);
-			pages += nr;
-			batch->nr -= nr;
+		free_pages_and_swap_cache(pages, nr);
+		pages += nr;
+		batch->nr -= nr;
 
-			cond_resched();
-		}
+		cond_resched();
 	}
+}
+
+static void tlb_batch_pages_flush(struct mmu_gather *tlb)
+{
+	struct mmu_gather_batch *batch;
+
+	for (batch = &tlb->local; batch && batch->nr; batch = batch->next)
+		__tlb_batch_free_encoded_pages(batch);
 	tlb->active = &tlb->local;
 }