diff --git a/CHANGELOG.md b/CHANGELOG.md
index 94b86133191..fd59fabaac0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,7 +26,7 @@
 * [ENHANCEMENT] Memberlist KV: incoming messages are now processed on per-key goroutine. This may reduce loss of "maintanance" packets in busy memberlist installations, but use more CPU. New `memberlist_client_received_broadcasts_dropped_total` counter tracks number of dropped per-key messages. #1912
 * [ENHANCEMENT] Blocks Storage, Alertmanager, Ruler: add support a prefix to the bucket store (`*_storage.storage_prefix`). This enables using the same bucket for the three components. #1686 #1951
 * [ENHANCEMENT] Upgrade Docker base images to `alpine:3.16.0`. #2028
-* [ENHANCEMENT] Store-gateway: Add experimental configuration option for the store-gateway to attempt to pre-populate the file system cache when memory-mapping index-header files. Enabled with `-blocks-storage.bucket-store.index-header.map-populate-enabled=true`. #2019
+* [ENHANCEMENT] Store-gateway: Add experimental configuration option for the store-gateway to attempt to pre-populate the file system cache when memory-mapping index-header files. Enabled with `-blocks-storage.bucket-store.index-header.map-populate-enabled=true`. Note this flag only has an effect when running on Linux. #2019 #2054
 * [ENHANCEMENT] Chunk Mapper: reduce memory usage of async chunk mapper. #2043
 * [BUGFIX] Fix regexp parsing panic for regexp label matchers with start/end quantifiers. #1883
 * [BUGFIX] Ingester: fixed deceiving error log "failed to update cached shipped blocks after shipper initialisation", occurring for each new tenant in the ingester. #1893
diff --git a/pkg/storegateway/indexheader/fileutil/mmap_generic.go b/pkg/storegateway/indexheader/fileutil/mmap_generic.go
new file mode 100644
index 00000000000..b0247c39982
--- /dev/null
+++ b/pkg/storegateway/indexheader/fileutil/mmap_generic.go
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+// Provenance-includes-location: https://github.com/prometheus/prometheus/blob/main/tsdb/fileutil/mmap_unix.go
+// Provenance-includes-license: Apache-2.0
+// Provenance-includes-copyright: The Prometheus Authors.
+
+//go:build darwin
+// +build darwin
+
+package fileutil
+
+import (
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func mmap(f *os.File, length int, populate bool) ([]byte, error) {
+	return unix.Mmap(int(f.Fd()), 0, length, unix.PROT_READ, unix.MAP_SHARED)
+}
+
+func munmap(b []byte) (err error) {
+	return unix.Munmap(b)
+}
diff --git a/pkg/storegateway/indexheader/fileutil/mmap_unix.go b/pkg/storegateway/indexheader/fileutil/mmap_unix.go
index 74894e9da75..4cf9c1974cb 100644
--- a/pkg/storegateway/indexheader/fileutil/mmap_unix.go
+++ b/pkg/storegateway/indexheader/fileutil/mmap_unix.go
@@ -3,8 +3,8 @@
 // Provenance-includes-license: Apache-2.0
 // Provenance-includes-copyright: The Prometheus Authors.
 
-//go:build !windows && !plan9
-// +build !windows,!plan9
+//go:build !darwin && !windows && !plan9
+// +build !darwin,!windows,!plan9
 
 package fileutil