Messages in this thread |  | | Date | Wed, 22 Oct 2014 10:28:57 +0900 | From | "karam.lee" <> | Subject | Re: [PATCH v3 3/3] zram: implement rw_page operation of zram |
| |
On Tue, Oct 21, 2014 at 03:57:29PM +0200, Jerome Marchand wrote: > On 10/21/2014 09:27 AM, karam.lee@lge.com wrote: > > 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> > > --- > > 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..696f0b5 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 = 1; > > Small nitpick, but why do you initialize ret to 1? It doesn't seem to be > ever used (nor is 1 a valid return value AFAICT). > > It otherwise looks good. > > Acked-by: Jerome Marchand <jmarchan@redhat.com> >
Thank you for reply. I agree with your opinion.
It was my mistake to initialize ret to 1.
I will resend the fixed version.
> > + 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 = -ENOMEM; > > + 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 > > }; > > > > > >
|  |