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-rw-r--r--include/asm-generic/tlb.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index ed6642ad03e..25f01d0bc14 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -78,6 +78,14 @@ struct mmu_gather_batch {
#define MAX_GATHER_BATCH \
((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))
+/*
+ * Limit the maximum number of mmu_gather batches to reduce a risk of soft
+ * lockups for non-preemptible kernels on huge machines when a lot of memory
+ * is zapped during unmapping.
+ * 10K pages freed at once should be safe even without a preemption point.
+ */
+#define MAX_GATHER_BATCH_COUNT (10000UL/MAX_GATHER_BATCH)
+
/* struct mmu_gather is an opaque type used by the mm code for passing around
* any data needed by arch specific code for tlb_remove_page.
*/
@@ -96,6 +104,7 @@ struct mmu_gather {
struct mmu_gather_batch *active;
struct mmu_gather_batch local;
struct page *__pages[MMU_GATHER_BUNDLE];
+ unsigned int batch_count;
};
#define HAVE_GENERIC_MMU_GATHER