diff options
| author | Minchan Kim <minchan@kernel.org> | 2020-12-14 19:14:28 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-15 12:13:47 -0800 |
| commit | 0d8359620d9be9823b6b9b3cf2dbe006cbfec594 (patch) | |
| tree | 6bd834d7f3607b69ab0ff17480e31d3ee38b8b36 /drivers/block | |
| parent | 95c9ae14a9b99a65956de80a1eefafcb901c0e9f (diff) | |
| download | lwn-0d8359620d9be9823b6b9b3cf2dbe006cbfec594.tar.gz lwn-0d8359620d9be9823b6b9b3cf2dbe006cbfec594.zip | |
zram: support page writeback
There is demand to writeback specific process pages to backing store
instead of all idles pages in the system due to storage wear out concerns
and to launching latency of apps which are most of the time idle but are
critical for resume latency.
This patch extends the writeback knob to support a specific page
writeback.
Link: https://lkml.kernel.org/r/20201020190506.3758660-1-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 21 |
1 files changed, 17 insertions, 4 deletions
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; |