--- zzzz-none-000/linux-4.4.271/drivers/block/zram/zram_drv.c	2021-06-03 06:22:09.000000000 +0000
+++ hawkeye-5590-750/linux-4.4.271/drivers/block/zram/zram_drv.c	2023-04-19 10:22:28.000000000 +0000
@@ -30,6 +30,8 @@
 #include <linux/err.h>
 #include <linux/idr.h>
 #include <linux/sysfs.h>
+#include <avm/sammel/debug.h>
+#include <avm/enh/semi_seq.h>
 
 #include "zram_drv.h"
 
@@ -1184,6 +1186,44 @@
 	.attrs = zram_disk_attrs,
 };
 
+static int oom_info_callback(struct notifier_block *block, unsigned long event, void *_data)
+{
+	struct zram *zram = container_of(block, struct zram, oom_info_block);
+	struct seq_file *file = _data;
+	struct zs_pool_stats pool_stats;
+	u64 orig_size, mem_used = 0;
+	long max_used;
+
+	memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats));
+
+	// Unlik mm_stat we don't use semaphores to lock the access here. This is needed as the
+	// info_callback is called in an atomic context.
+	//
+	// All of the calls made here are either normal reads or atomic reads. Which can be done
+	// unguarded. The worst is, that we get inconsistent data, which should be easily detectable
+	// by inspecting the output.
+	if (init_done(zram)) {
+		mem_used = zs_get_total_pages(zram->meta->mem_pool);
+		zs_pool_stats(zram->meta->mem_pool, &pool_stats);
+	}
+
+	orig_size = atomic64_read(&zram->stats.pages_stored);
+	max_used = atomic_long_read(&zram->stats.max_used_pages);
+
+	sseq_printf(file,
+			"%s: orig:%lluKiB compr:%lluKiB used:%lluKiB limit:%luKiB max:%ldKiB zero:%llu compact:%ld\n",
+			zram->disk->disk_name,
+			orig_size << (PAGE_SHIFT - 10),
+			(u64)atomic64_read(&zram->stats.compr_data_size) >> 10,
+			mem_used << (PAGE_SHIFT - 10),
+			zram->limit_pages << (PAGE_SHIFT - 10),
+			max_used << (PAGE_SHIFT - 10),
+			(u64)atomic64_read(&zram->stats.zero_pages),
+			(long)atomic_long_read(&pool_stats.pages_compacted));
+
+	return NOTIFY_DONE;
+}
+
 static const struct attribute_group *zram_disk_attr_groups[] = {
 	&zram_disk_attr_group,
 	NULL,
@@ -1276,6 +1316,9 @@
 	zram->meta = NULL;
 	zram->max_comp_streams = 1;
 
+	zram->oom_info_block.notifier_call = oom_info_callback;
+	avm_oom_info_chain_register(&zram->oom_info_block);
+
 	pr_info("Added device: %s\n", zram->disk->disk_name);
 	return device_id;
 
@@ -1306,6 +1349,8 @@
 	zram->claim = true;
 	mutex_unlock(&bdev->bd_mutex);
 
+	avm_oom_info_chain_unregister(&zram->oom_info_block);
+
 	/* Make sure all the pending I/O are finished */
 	fsync_bdev(bdev);
 	zram_reset_device(zram);