On Wed, 26 Feb 2014 15:27:56 +0300 Sergey Senozhatsky <[email protected]> wrote:
> This is preparation patch to add multi stream support to zcomp. > > Introduce struct zcomp_strm_single and a set of functions to manage zcomp_strm > stream access. zcomp_strm_single implements single compession stream, same way > as current zcomp implementation. This moves zcomp_strm stream control and > locking from zcomp, so compressing backend zcomp is not aware of required > locking. > > Single and multi streams require different locking schemes. Minchan Kim > reported that spinlock-based locking scheme (which is used in multi stream > implementation) has demonstrated a severe perfomance regression for single > compression stream case, comparing to mutex-based. > see https://lkml.org/lkml/2014/2/18/16 > > The following set of functions added: > - zcomp_strm_single_get()/zcomp_strm_single_put() > get and put compression stream, implement required locking > - zcomp_strm_single_create()/zcomp_strm_single_destroy() > create and destroy zcomp_strm_single > > New ->strm_get() and ->strm_put() callbacks added to zcomp, which are set to > zcomp_strm_single_get() and zcomp_strm_single_put() during initialisation. > Instead of direct locking and zcomp_strm access from zcomp_strm_get() and > zcomp_strm_put(), zcomp now calls ->strm_get() and ->strm_put() > correspondingly. > > ... > > +static struct zcomp_strm *zcomp_strm_single_get(struct zcomp *comp) > +{ > + struct zcomp_strm_single *zs = comp->stream; > + mutex_lock(&zs->strm_lock); > + return zs->zstrm; > +} > + > +static void zcomp_strm_single_put(struct zcomp *comp, struct zcomp_strm > *zstrm) > +{ > + struct zcomp_strm_single *zs = comp->stream; > + mutex_unlock(&zs->strm_lock); > +} Again, these are not "get" and "put" operations. > > ... > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
