From 44529da8525ef811ea8cc7704ffa9910459656ce Mon Sep 17 00:00:00 2001
From: David Goldblatt <davidgoldblatt@fb.com>
Date: Sat, 29 Feb 2020 10:48:59 -0800
Subject: [PATCH] Cache-bin: Make flush modifications internal

I.e. the tcache code just calls a cache-bin function to finish flush (and move
pointers around, etc.).  It doesn't directly access the cache-bin's owned memory
any more.
---
 include/jemalloc/internal/cache_bin.h | 18 +++++++++++++++++-
 src/tcache.c                          |  8 ++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/include/jemalloc/internal/cache_bin.h b/include/jemalloc/internal/cache_bin.h
index 6895dca2..382883cd 100644
--- a/include/jemalloc/internal/cache_bin.h
+++ b/include/jemalloc/internal/cache_bin.h
@@ -267,7 +267,7 @@ cache_bin_init_ptr_array_for_fill(cache_bin_t *bin, cache_bin_info_t *info,
  */
 static inline void
 cache_bin_finish_fill(cache_bin_t *bin, cache_bin_info_t *info,
-    cache_bin_ptr_array_t *arr, szind_t nfilled) {
+    cache_bin_ptr_array_t *arr, cache_bin_sz_t nfilled) {
 	assert(cache_bin_ncached_get(bin, info) == 0);
 	if (nfilled < arr->n) {
 		void **empty_position = cache_bin_empty_position_get(bin, info);
@@ -285,6 +285,10 @@ cache_bin_init_ptr_array_for_flush(cache_bin_t *bin, cache_bin_info_t *info,
 	    || *arr->ptr != NULL);
 }
 
+/*
+ * These accessors are used by the flush pathways -- they reverse ordinary flush
+ * ordering.
+ */
 JEMALLOC_ALWAYS_INLINE void *
 cache_bin_ptr_array_get(cache_bin_ptr_array_t *arr, cache_bin_sz_t n) {
 	return *(arr->ptr - n);
@@ -295,4 +299,16 @@ cache_bin_ptr_array_set(cache_bin_ptr_array_t *arr, cache_bin_sz_t n, void *p) {
 	*(arr->ptr - n) = p;
 }
 
+static inline void
+cache_bin_finish_flush(cache_bin_t *bin, cache_bin_info_t *info,
+    cache_bin_ptr_array_t *arr, cache_bin_sz_t nflushed) {
+	unsigned rem = cache_bin_ncached_get(bin, info) - nflushed;
+	memmove(bin->cur_ptr.ptr + nflushed, bin->cur_ptr.ptr,
+	    rem * sizeof(void *));
+	cache_bin_ncached_set(bin, info, rem);
+	if (bin->cur_ptr.lowbits > bin->low_water_position) {
+		bin->low_water_position = bin->cur_ptr.lowbits;
+	}
+}
+
 #endif /* JEMALLOC_INTERNAL_CACHE_BIN_H */
diff --git a/src/tcache.c b/src/tcache.c
index 3c6d5d76..e7188585 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -346,12 +346,8 @@ tcache_bin_flush_impl(tsd_t *tsd, tcache_t *tcache, cache_bin_t *tbin,
 		}
 	}
 
-	memmove(tbin->cur_ptr.ptr + (ncached - rem), tbin->cur_ptr.ptr, rem *
-	    sizeof(void *));
-	cache_bin_ncached_set(tbin, &tcache_bin_info[binind], rem);
-	if (tbin->cur_ptr.lowbits > tbin->low_water_position) {
-		tbin->low_water_position = tbin->cur_ptr.lowbits;
-	}
+	cache_bin_finish_flush(tbin, &tcache_bin_info[binind], &ptrs,
+	    ncached - rem);
 }
 
 void