Messages in this thread Patch in this message |  | | From | karam.lee@lge ... | Subject | [PATCH v6 3/3] zram: implement rw_page operation of zram | Date | Thu, 23 Oct 2014 15:49:07 +0900 |
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From: "karam.lee" <karam.lee@lge.com>
This patch implements rw_page operation for zram block device.
I implemented the feature in zram and tested it. Test bed was the G2, LG electronic mobile device, whtich has msm8974 processor and 2GB memory. With a memory allocation test program consuming memory, the system generates swap. And operating time of swap_write_page() was measured.
-------------------------------------------------- | | operating time | improvement | | | (20 runs average) | | -------------------------------------------------- |with patch | 1061.15 us | +2.4% | -------------------------------------------------- |without patch| 1087.35 us | | --------------------------------------------------
Each test(with paged_io,with BIO) result set shows normal distribution and has equal variance. I mean the two values are valid result to compare. I can say operation with paged I/O(without BIO) is faster 2.4% with confidence level 95%.
Signed-off-by: karam.lee <karam.lee@lge.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Jerome Marchand <jmarchan@redhat.com> CC: Matthew Wilcox <matthew.r.wilcox@intel.com> --- drivers/block/zram/zram_drv.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 4565fdc..8d3086a 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -810,8 +810,46 @@ static void zram_slot_free_notify(struct block_device *bdev, atomic64_inc(&zram->stats.notify_free); } +static int zram_rw_page(struct block_device *bdev, sector_t sector, + struct page *page, int rw) +{ + int offset, ret; + u32 index; + struct zram *zram; + struct bio_vec bv; + + zram = bdev->bd_disk->private_data; + if (!valid_io_request(zram, sector, PAGE_SIZE)) { + atomic64_inc(&zram->stats.invalid_io); + ret = -EINVAL; + goto out; + } + + down_read(&zram->init_lock); + if (unlikely(!init_done(zram))) { + ret = -EIO; + goto out_unlock; + } + + index = sector >> SECTORS_PER_PAGE_SHIFT; + offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT; + + bv.bv_page = page; + bv.bv_len = PAGE_SIZE; + bv.bv_offset = 0; + + ret = zram_bvec_rw(zram, &bv, index, offset, rw); + +out_unlock: + up_read(&zram->init_lock); +out: + page_endio(page, rw, ret); + return ret; +} + static const struct block_device_operations zram_devops = { .swap_slot_free_notify = zram_slot_free_notify, + .rw_page = zram_rw_page, .owner = THIS_MODULE }; -- 1.7.9.5
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