lkml.org 
[lkml]   [2014]   [Feb]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCHv6 5/6] zram: enalbe multi stream compression support in zram
On Tue, Feb 25, 2014 at 03:25:22AM +0300, Sergey Senozhatsky wrote:
> On (02/25/14 09:12), Minchan Kim wrote:
> > On Tue, Feb 25, 2014 at 02:58:24AM +0300, Sergey Senozhatsky wrote:
> > > On (02/25/14 08:53), Minchan Kim wrote:
> > > > On Fri, Feb 21, 2014 at 02:50:42PM +0300, Sergey Senozhatsky wrote:
> > > > > 1) Add ZRAM_MULTI_STREAM configuration option and make multi stream
> > > > > zcomp support available.
> > > > >
> > > > > 2) Introduce zram device attribute max_comp_streams to show and store
> > > > > current zcomp's max number of zcomp streams (num_strm).
> > > > >
> > > > > 3) Extend zcomp zcomp_create() with `num_strm' parameter. `num_strm'
> > > > > limits the number of zcomp_strm structs in compression backend's idle
> > > > > list (max_comp_streams).
> > > > >
> > > > > If ZRAM_MULTI_STREAM option selected:
> > > > > -- user can change max number of compression streams (max_comp_streams),
> > > > > otherwise, attempt to change its default value (1) will be ignored.
> > > > > -- passing to zcomp_create() num_strm equals to 1 will initialise zcomp
> > > > > using single compression stream zcomp_strm_single (mutex-based locking)
> > > > > -- passing to zcomp_create() num_strm greater than 1 will initialise zcomp
> > > > > using multi compression stream zcomp_strm_multi (spinlock-based locking)
> > > > >
> > > > > If ZRAM_MULTI_STREAM has not been selected, only single compression stream
> > > > > support available.
> > > > >
> > > > > iozone -t 3 -R -r 16K -s 60M -I +Z
> > > > >
> > > > > test base 1 strm (mutex) 3 strm (spinlock)
> > > > > -----------------------------------------------------------------------
> > > > > Initial write 589286.78 583518.39 718011.05
> > > > > Rewrite 604837.97 596776.38 1515125.72
> > > > > Random write 584120.11 595714.58 1388850.25
> > > > > Pwrite 535731.17 541117.38 739295.27
> > > > > Fwrite 1418083.88 1478612.72 1484927.06
> > > > >
> > > > > Usage example:
> > > > > set max_comp_streams to 4
> > > > > echo 4 > /sys/block/zram0/max_comp_streams
> > > > >
> > > > > show current max_comp_streams (default value is 1).
> > > > > cat /sys/block/zram0/max_comp_streams
> > > > >
> > > > > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > > > > ---
> > > > > drivers/block/zram/Kconfig | 10 ++++++++++
> > > > > drivers/block/zram/zcomp.c | 13 +++++++++++--
> > > > > drivers/block/zram/zcomp.h | 2 +-
> > > > > drivers/block/zram/zram_drv.c | 43 ++++++++++++++++++++++++++++++++++++++++++-
> > > > > drivers/block/zram/zram_drv.h | 2 +-
> > > > > 5 files changed, 65 insertions(+), 5 deletions(-)
> > > > >
> > > > > diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
> > > > > index 3450be8..a2ba9a9 100644
> > > > > --- a/drivers/block/zram/Kconfig
> > > > > +++ b/drivers/block/zram/Kconfig
> > > > > @@ -15,6 +15,16 @@ config ZRAM
> > > > >
> > > > > See zram.txt for more information.
> > > > >
> > > > > +config ZRAM_MULTI_STREAM
> > > > > + bool "Multi stream compression support"
> > > > > + depends on ZRAM
> > > > > + default n
> > > > > + help
> > > > > + This option adds additional functionality to ZRAM, that enables
> > > > > + multi compression stream support and provides ability to control
> > > > > + maximum number of parallel compressions using max_comp_streams
> > > > > + device attribute.
> > > > > +
> > > > > config ZRAM_DEBUG
> > > > > bool "Compressed RAM block device debug support"
> > > > > depends on ZRAM
> > > > > diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
> > > > > index 41325ed..7faa6bd 100644
> > > > > --- a/drivers/block/zram/zcomp.c
> > > > > +++ b/drivers/block/zram/zcomp.c
> > > > > @@ -240,8 +240,9 @@ void zcomp_destroy(struct zcomp *comp)
> > > > > * if requested algorithm is not supported or in case
> > > > > * of init error
> > > > > */
> > > > > -struct zcomp *zcomp_create(const char *compress)
> > > > > +struct zcomp *zcomp_create(const char *compress, int num_strm)
> > > > > {
> > > > > + int ret;
> > > > > struct zcomp *comp;
> > > > > struct zcomp_backend *backend;
> > > > >
> > > > > @@ -254,7 +255,15 @@ struct zcomp *zcomp_create(const char *compress)
> > > > > return NULL;
> > > > >
> > > > > comp->backend = backend;
> > > > > - if (zcomp_strm_single_create(comp) != 0) {
> > > > > +#ifdef CONFIG_ZRAM_MULTI_STREAM
> > > > > + if (num_strm > 1)
> > > > > + ret = zcomp_strm_multi_create(comp, num_strm);
> > > > > + else
> > > > > + ret = zcomp_strm_single_create(comp);
> > > > > +#else
> > > > > + ret = zcomp_strm_single_create(comp);
> > > > > +#endif
> > > > > + if (ret != 0) {
> > > > > zcomp_destroy(comp);
> > > > > return NULL;
> > > > > }
> > > > > diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
> > > > > index 8dc1d7f..d7e1229 100644
> > > > > --- a/drivers/block/zram/zcomp.h
> > > > > +++ b/drivers/block/zram/zcomp.h
> > > > > @@ -42,7 +42,7 @@ struct zcomp {
> > > > > void (*destroy)(struct zcomp *comp);
> > > > > };
> > > > >
> > > > > -struct zcomp *zcomp_create(const char *comp);
> > > > > +struct zcomp *zcomp_create(const char *comp, int num_strm);
> > > > > void zcomp_destroy(struct zcomp *comp);
> > > > >
> > > > > struct zcomp_strm *zcomp_strm_get(struct zcomp *comp);
> > > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > > > > index 200c12a..c147e6f 100644
> > > > > --- a/drivers/block/zram/zram_drv.c
> > > > > +++ b/drivers/block/zram/zram_drv.c
> > > > > @@ -107,6 +107,42 @@ static ssize_t mem_used_total_show(struct device *dev,
> > > > > return sprintf(buf, "%llu\n", val);
> > > > > }
> > > > >
> > > > > +static ssize_t max_comp_streams_show(struct device *dev,
> > > > > + struct device_attribute *attr, char *buf)
> > > > > +{
> > > > > + long val;
> > > >
> > > > Why 'long'?
> > > >
> > > > > + struct zram *zram = dev_to_zram(dev);
> > > > > +
> > > > > + down_read(&zram->init_lock);
> > > > > + val = zram->max_comp_streams;
> > > > > + up_read(&zram->init_lock);
> > > > > +
> > > > > + return sprintf(buf, "%ld\n", val);
> > > > > +}
> > > > > +
> > > > > +static ssize_t max_comp_streams_store(struct device *dev,
> > > > > + struct device_attribute *attr, const char *buf, size_t len)
> > > > > +{
> > > > > +#ifdef CONFIG_ZRAM_MULTI_STREAM
> > > > > + long num;
> > > > > + struct zram *zram = dev_to_zram(dev);
> > > > > +
> > > > > + if (kstrtol(buf, 0, &num))
> > > > > + return -EINVAL;
> > > > > + if (num < 1)
> > > > > + return -EINVAL;
> > > > > + down_write(&zram->init_lock);
> > > > > + if (init_done(zram)) {
> > > > > + up_write(&zram->init_lock);
> > > > > + pr_info("Can't set max_comp_streams for initialized device\n");
> > > > > + return -EBUSY;
> > > > > + }
> > > > > + zram->max_comp_streams = num;
> > > > > + up_write(&zram->init_lock);
> > > >
> > > > If user decrease max stream in runtime, who care of freeing streams?
> > > >
> > >
> > > at the moment (to make it simpler), user can set max stream number
> > > only for un-initialised device. once zcomp created and initialised
> > > user cannot change max streams
> >
> > Hmm, I hope we have the abilitiy in the first place because I think
> > it's not complicate and make test very handy. Please.
> >
>
> ok, I'll take a look. I'm not sure that I'll finish it tonight.
> I need to think about it for a moment. probably it will require
> several additional counters in zcomp_strm_multi -- max_strms
> and num_strms (num_strms equals to number of currently allocated
> streams). user may decrease (for example) max streams while every
> available stream is busy (idle list is empty), so we need to check
> max_strms and avail_strms while we _put() stream. and we definitely
> don't want max_strms for zcomp_strm_multi to be less than 2 :-)
>
> so far I've address your notes and concerns -- no CONFIG option,
> both multi and single streams options, etc.

Thanks!

--
Kind regards,
Minchan Kim


\
 
 \ /
  Last update: 2014-02-25 02:21    [W:0.059 / U:0.240 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site