Date: Tue, 5 Jun 2018 15:52:15 -0700 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Mateusz Guzik <mjguzik@gmail.com> Cc: Eric van Gyzen <eric@vangyzen.net>, Mateusz Guzik <mjg@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r334545 - in head/sys: contrib/zstd/lib/freebsd kern netinet/libalias sys Message-ID: <20180605225215.GC1005@FreeBSD.org> In-Reply-To: <CAGudoHGcZ9b8fvQVx-%2Bxqsr47GzrTZR6%2Bh2C_EqTp3rSjGvATw@mail.gmail.com> References: <201806022220.w52MK9TT026244@repo.freebsd.org> <1b77e282-e24b-d14c-9811-4cf214d58280@vangyzen.net> <CAGudoHGcZ9b8fvQVx-%2Bxqsr47GzrTZR6%2Bh2C_EqTp3rSjGvATw@mail.gmail.com>
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On Tue, Jun 05, 2018 at 06:35:37PM +0200, Mateusz Guzik wrote:
M> > On 06/02/2018 17:20, Mateusz Guzik wrote:
M> > > +#ifdef _KERNEL
M> > > +#define malloc(size, type, flags) ({ \
M> > > + void *_malloc_item; \
M> > > + size_t _size = (size); \
M> > > + if (__builtin_constant_p(size) && __builtin_constant_p(flags) &&\
M> > > + ((flags) & M_ZERO)) { \
M> > > + _malloc_item = malloc(_size, type, (flags) &~ M_ZERO); \
M> > > + if (((flags) & M_WAITOK) || _malloc_item != NULL) \
M> > > + bzero(_malloc_item, _size); \
M> > > + } else { \
M> > > + _malloc_item = malloc(_size, type, flags); \
M> > > + } \
M> > > + _malloc_item; \
M> > > +})
M> > > +#endif
M> >
M> > Mateusz,
M> >
M> > Thank you for this and for all of your performance work. It is all very
M> > interesting stuff.
M> >
M> >
M> Thank you for the kind words. It is positive feedback like this which
M> keeps me going!
Btw, what was the point of checking flags || result? Most places in kernel
ignore flags and just test result regerdless of M_WAITOK/M_NOWAIT.
The result is already in a register, why do you think checking for absense
of M_WAITOK is faster that checking for !NULL _malloc_item?
--
Gleb Smirnoff
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