| Message ID | b38d8936eaddd524d19823f7429138e2ef24e0d1.1726074904.git.lorenzo.stoakes@oracle.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | minmax: reduce egregious min/max macro expansion | expand |
Hi, On 9/11/24 7:51 PM, Lorenzo Stoakes wrote: > Avoid unnecessary nested min()/max() which results in egregious macro > expansion. Use clamp_t() as this introduces the least possible expansion. > > Not doing so results in an impact on build times. > > This resolves an issue with slackware 15.0 32-bit compilation as reported > by Richard Narron. > > Presumably the min/max fixups would be difficult to backport, this patch > should be easier and fix's Richard's problem in 5.15. > > Reported-by: Richard Narron <richard@aaazen.com> > Closes: https://lore.kernel.org/all/4a5321bd-b1f-1832-f0c-cea8694dc5aa@aaazen.com/ > Fixes: 867046cc7027 ("minmax: relax check to allow comparison between unsigned arguments and signed constants") > Cc: stable@vger.kernel.org > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Thanks, patch looks good to me: Reviewed-by: Hans de Goede <hdegoede@redhat.com> Regards, Hans > --- > .../staging/media/atomisp/pci/sh_css_frac.h | 26 ++++++++++++++----- > 1 file changed, 19 insertions(+), 7 deletions(-) > > diff --git a/drivers/staging/media/atomisp/pci/sh_css_frac.h b/drivers/staging/media/atomisp/pci/sh_css_frac.h > index b90b5b330dfa..8ba65161f7a9 100644 > --- a/drivers/staging/media/atomisp/pci/sh_css_frac.h > +++ b/drivers/staging/media/atomisp/pci/sh_css_frac.h > @@ -32,12 +32,24 @@ > #define uISP_VAL_MAX ((unsigned int)((1 << uISP_REG_BIT) - 1)) > > /* a:fraction bits for 16bit precision, b:fraction bits for ISP precision */ > -#define sDIGIT_FITTING(v, a, b) \ > - min_t(int, max_t(int, (((v) >> sSHIFT) >> max(sFRACTION_BITS_FITTING(a) - (b), 0)), \ > - sISP_VAL_MIN), sISP_VAL_MAX) > -#define uDIGIT_FITTING(v, a, b) \ > - min((unsigned int)max((unsigned)(((v) >> uSHIFT) \ > - >> max((int)(uFRACTION_BITS_FITTING(a) - (b)), 0)), \ > - uISP_VAL_MIN), uISP_VAL_MAX) > +static inline int sDIGIT_FITTING(int v, int a, int b) > +{ > + int fit_shift = sFRACTION_BITS_FITTING(a) - b; > + > + v >>= sSHIFT; > + v >>= fit_shift > 0 ? fit_shift : 0; > + > + return clamp_t(int, v, sISP_VAL_MIN, sISP_VAL_MAX); > +} > + > +static inline unsigned int uDIGIT_FITTING(unsigned int v, int a, int b) > +{ > + int fit_shift = uFRACTION_BITS_FITTING(a) - b; > + > + v >>= uSHIFT; > + v >>= fit_shift > 0 ? fit_shift : 0; > + > + return clamp_t(unsigned int, v, uISP_VAL_MIN, uISP_VAL_MAX); > +} > > #endif /* __SH_CSS_FRAC_H */ > -- > 2.46.0 >
On Wed, 11 Sept 2024 at 10:51, Lorenzo Stoakes <lorenzo.stoakes@oracle.com> wrote: > > Avoid unnecessary nested min()/max() which results in egregious macro > expansion. Use clamp_t() as this introduces the least possible expansion. I took this (single) patch directly, since that's the one that actually causes build problems in limited environments (admittedly not in current git with the more invasive min/max cleanups, but in order to be back-ported). Plus it cleans up the code with more legible inline functions, rather than just doing some minimal syntactic changes. I expanded on the commit message to say that. The two others I'll leave for now and see what maintainers of their respective areas think. Linus
diff --git a/drivers/staging/media/atomisp/pci/sh_css_frac.h b/drivers/staging/media/atomisp/pci/sh_css_frac.h index b90b5b330dfa..8ba65161f7a9 100644 --- a/drivers/staging/media/atomisp/pci/sh_css_frac.h +++ b/drivers/staging/media/atomisp/pci/sh_css_frac.h @@ -32,12 +32,24 @@ #define uISP_VAL_MAX ((unsigned int)((1 << uISP_REG_BIT) - 1)) /* a:fraction bits for 16bit precision, b:fraction bits for ISP precision */ -#define sDIGIT_FITTING(v, a, b) \ - min_t(int, max_t(int, (((v) >> sSHIFT) >> max(sFRACTION_BITS_FITTING(a) - (b), 0)), \ - sISP_VAL_MIN), sISP_VAL_MAX) -#define uDIGIT_FITTING(v, a, b) \ - min((unsigned int)max((unsigned)(((v) >> uSHIFT) \ - >> max((int)(uFRACTION_BITS_FITTING(a) - (b)), 0)), \ - uISP_VAL_MIN), uISP_VAL_MAX) +static inline int sDIGIT_FITTING(int v, int a, int b) +{ + int fit_shift = sFRACTION_BITS_FITTING(a) - b; + + v >>= sSHIFT; + v >>= fit_shift > 0 ? fit_shift : 0; + + return clamp_t(int, v, sISP_VAL_MIN, sISP_VAL_MAX); +} + +static inline unsigned int uDIGIT_FITTING(unsigned int v, int a, int b) +{ + int fit_shift = uFRACTION_BITS_FITTING(a) - b; + + v >>= uSHIFT; + v >>= fit_shift > 0 ? fit_shift : 0; + + return clamp_t(unsigned int, v, uISP_VAL_MIN, uISP_VAL_MAX); +} #endif /* __SH_CSS_FRAC_H */
Avoid unnecessary nested min()/max() which results in egregious macro expansion. Use clamp_t() as this introduces the least possible expansion. Not doing so results in an impact on build times. This resolves an issue with slackware 15.0 32-bit compilation as reported by Richard Narron. Presumably the min/max fixups would be difficult to backport, this patch should be easier and fix's Richard's problem in 5.15. Reported-by: Richard Narron <richard@aaazen.com> Closes: https://lore.kernel.org/all/4a5321bd-b1f-1832-f0c-cea8694dc5aa@aaazen.com/ Fixes: 867046cc7027 ("minmax: relax check to allow comparison between unsigned arguments and signed constants") Cc: stable@vger.kernel.org Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> --- .../staging/media/atomisp/pci/sh_css_frac.h | 26 ++++++++++++++----- 1 file changed, 19 insertions(+), 7 deletions(-) -- 2.46.0