New option ZRAM_NON_SWAP add a interface "non_swap" to zram.
User can set a unsigned int value to zram.
If a page that compressed size is bigger than limit, mark it as
non-swap. Then this page will add to unevictable lru list.
This patch doesn't handle the shmem file pages.
Signed-off-by: Hui Zhu <zhuhui@xxxxxxxxxx>
---
drivers/block/zram/Kconfig | 11 +++++++++++
drivers/block/zram/zram_drv.c | 39 +++++++++++++++++++++++++++++++++++++++
drivers/block/zram/zram_drv.h | 4 ++++
3 files changed, 54 insertions(+)
diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index b8ecba6..525caaa 100644
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -13,3 +13,14 @@ config ZRAM
disks and maybe many more.
See zram.txt for more information.
+
+config ZRAM_NON_SWAP
+ bool "Enable zram non-swap support"
+ depends on ZRAM
+ select NON_SWAP
+ default n
+ help
+ This option add a interface "non_swap" to zram. User can set
+ a unsigned int value to zram.
+ If a page that compressed size is bigger than limit, mark it as
+ non-swap. Then this page will add to unevictable lru list.
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 04365b1..8f7f1ec 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -714,6 +714,14 @@ compress_again:
goto out;
}
+#ifdef CONFIG_ZRAM_NON_SWAP
+ if (!is_partial_io(bvec) && PageAnon(page) &&
+ zram->non_swap && clen > zram->non_swap) {
+ ret = 0;
+ SetPageNonSwap(page);
+ goto out;
+ }
+#endif
src = zstrm->buffer;
if (unlikely(clen > max_zpage_size)) {
clen = PAGE_SIZE;
@@ -1180,6 +1188,31 @@ static const struct block_device_operations zram_devops = {
.owner = THIS_MODULE
};
+#ifdef CONFIG_ZRAM_NON_SWAP
+static ssize_t non_swap_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%u\n", zram->non_swap);
+}
+
+static ssize_t non_swap_store(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t len)
+{
+ struct zram *zram = dev_to_zram(dev);
+
+ zram->non_swap = (unsigned int)memparse(buf, NULL);
+
+ if (zram->non_swap > max_zpage_size)
+ pr_warn("Nonswap should small than max_zpage_size %zu\n",
+ max_zpage_size);
+
+ return len;
+}
+#endif
+
static DEVICE_ATTR_WO(compact);
static DEVICE_ATTR_RW(disksize);
static DEVICE_ATTR_RO(initstate);
@@ -1190,6 +1223,9 @@ static DEVICE_ATTR_RW(mem_limit);
static DEVICE_ATTR_RW(mem_used_max);
static DEVICE_ATTR_RW(max_comp_streams);
static DEVICE_ATTR_RW(comp_algorithm);
+#ifdef CONFIG_ZRAM_NON_SWAP
+static DEVICE_ATTR_RW(non_swap);
+#endif
static struct attribute *zram_disk_attrs[] = {
&dev_attr_disksize.attr,
@@ -1210,6 +1246,9 @@ static struct attribute *zram_disk_attrs[] = {
&dev_attr_mem_used_max.attr,
&dev_attr_max_comp_streams.attr,
&dev_attr_comp_algorithm.attr,
+#ifdef CONFIG_ZRAM_NON_SWAP
+ &dev_attr_non_swap.attr,
+#endif
&dev_attr_io_stat.attr,
&dev_attr_mm_stat.attr,
&dev_attr_debug_stat.attr,
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 74fcf10..bd5f38a 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -119,5 +119,9 @@ struct zram {
* zram is claimed so open request will be failed
*/
bool claim; /* Protected by bdev->bd_mutex */
+
+#ifdef CONFIG_ZRAM_NON_SWAP
+ unsigned int non_swap;
+#endif
};
#endif
--
1.9.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>