diff options
| -rw-r--r-- | Documentation/admin-guide/blockdev/zram.rst | 5 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 21 |
2 files changed, 22 insertions, 4 deletions
diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index a6fd1f9b5faf..8f3cfa42e443 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -334,6 +334,11 @@ Admin can request writeback of those idle pages at right timing via:: With the command, zram writeback idle pages from memory to the storage. +If admin want to write a specific page in zram device to backing device, +they could write a page index into the interface. + + echo "page_index=1251" > /sys/block/zramX/writeback + If there are lots of write IO with flash device, potentially, it has flash wearout problem so that admin needs to design write limitation to guarantee storage health for entire product life. diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 1b697208d661..9a1e6ee4dbef 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -620,15 +620,19 @@ static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec, return 1; } +#define PAGE_WB_SIG "page_index=" + +#define PAGE_WRITEBACK 0 #define HUGE_WRITEBACK 1 #define IDLE_WRITEBACK 2 + static ssize_t writeback_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { struct zram *zram = dev_to_zram(dev); unsigned long nr_pages = zram->disksize >> PAGE_SHIFT; - unsigned long index; + unsigned long index = 0; struct bio bio; struct bio_vec bio_vec; struct page *page; @@ -640,8 +644,17 @@ static ssize_t writeback_store(struct device *dev, mode = IDLE_WRITEBACK; else if (sysfs_streq(buf, "huge")) mode = HUGE_WRITEBACK; - else - return -EINVAL; + else { + if (strncmp(buf, PAGE_WB_SIG, sizeof(PAGE_WB_SIG) - 1)) + return -EINVAL; + + ret = kstrtol(buf + sizeof(PAGE_WB_SIG) - 1, 10, &index); + if (ret || index >= nr_pages) + return -EINVAL; + + nr_pages = 1; + mode = PAGE_WRITEBACK; + } down_read(&zram->init_lock); if (!init_done(zram)) { @@ -660,7 +673,7 @@ static ssize_t writeback_store(struct device *dev, goto release_init_lock; } - for (index = 0; index < nr_pages; index++) { + while (nr_pages--) { struct bio_vec bvec; bvec.bv_page = page; |