* [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless @ 2015-10-10 10:56 Jason A. Donenfeld 2015-10-11 19:59 ` Thomas Hellstrom 2016-08-10 12:24 ` Fwd: " Thomas Hellstrom 0 siblings, 2 replies; 14+ messages in thread From: Jason A. Donenfeld @ 2015-10-10 10:56 UTC (permalink / raw) To: Dave Airlie, Thomas Hellstrom, linux-kernel; +Cc: Jason A. Donenfeld On most platforms, there exists this ifdef: #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) This makes this patch functionally useless. However, on PPC, there is actually an explicit definition of atomic_inc_not_zero with its own assembly that is slightly more optimized than atomic_add_unless. So, this patch changes kref to use atomic_inc_not_zero instead, for PPC and any future platforms that might provide an explicit implementation. This also puts this usage of kref more in line with a verbatim reading of the examples in Paul McKenney's paper [1] in the section titled "2.4 Atomic Counting With Check and Release Memory Barrier", which uses atomic_inc_not_zero. [1] http://open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2167.pdf Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- include/linux/kref.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/kref.h b/include/linux/kref.h index 484604d..83d1f94 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, */ static inline int __must_check kref_get_unless_zero(struct kref *kref) { - return atomic_add_unless(&kref->refcount, 1, 0); + return atomic_inc_not_zero(&kref->refcount); } #endif /* _KREF_H_ */ -- 2.6.0 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2015-10-10 10:56 [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless Jason A. Donenfeld @ 2015-10-11 19:59 ` Thomas Hellstrom 2016-02-01 21:53 ` Jason A. Donenfeld 2016-12-15 4:58 ` Jason A. Donenfeld 2016-08-10 12:24 ` Fwd: " Thomas Hellstrom 1 sibling, 2 replies; 14+ messages in thread From: Thomas Hellstrom @ 2015-10-11 19:59 UTC (permalink / raw) To: Jason A. Donenfeld, Dave Airlie, linux-kernel Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: > On most platforms, there exists this ifdef: > > #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) > > This makes this patch functionally useless. However, on PPC, there is > actually an explicit definition of atomic_inc_not_zero with its own > assembly that is slightly more optimized than atomic_add_unless. So, > this patch changes kref to use atomic_inc_not_zero instead, for PPC and > any future platforms that might provide an explicit implementation. > > This also puts this usage of kref more in line with a verbatim reading > of the examples in Paul McKenney's paper [1] in the section titled "2.4 > Atomic Counting With Check and Release Memory Barrier", which uses > atomic_inc_not_zero. > > [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= > > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > include/linux/kref.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/kref.h b/include/linux/kref.h > index 484604d..83d1f94 100644 > --- a/include/linux/kref.h > +++ b/include/linux/kref.h > @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, > */ > static inline int __must_check kref_get_unless_zero(struct kref *kref) > { > - return atomic_add_unless(&kref->refcount, 1, 0); > + return atomic_inc_not_zero(&kref->refcount); > } > #endif /* _KREF_H_ */ ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2015-10-11 19:59 ` Thomas Hellstrom @ 2016-02-01 21:53 ` Jason A. Donenfeld 2016-06-29 22:52 ` Jason A. Donenfeld 2016-12-15 4:58 ` Jason A. Donenfeld 1 sibling, 1 reply; 14+ messages in thread From: Jason A. Donenfeld @ 2016-02-01 21:53 UTC (permalink / raw) To: Thomas Hellstrom, Dave Airlie; +Cc: LKML, Paul McKenney This was positively reviewed but never picked up. Can someone queue this for rc3? Thanks, Jason On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote: > Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> > > > On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: >> On most platforms, there exists this ifdef: >> >> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) >> >> This makes this patch functionally useless. However, on PPC, there is >> actually an explicit definition of atomic_inc_not_zero with its own >> assembly that is slightly more optimized than atomic_add_unless. So, >> this patch changes kref to use atomic_inc_not_zero instead, for PPC and >> any future platforms that might provide an explicit implementation. >> >> This also puts this usage of kref more in line with a verbatim reading >> of the examples in Paul McKenney's paper [1] in the section titled "2.4 >> Atomic Counting With Check and Release Memory Barrier", which uses >> atomic_inc_not_zero. >> >> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= >> >> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> >> --- >> include/linux/kref.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/linux/kref.h b/include/linux/kref.h >> index 484604d..83d1f94 100644 >> --- a/include/linux/kref.h >> +++ b/include/linux/kref.h >> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, >> */ >> static inline int __must_check kref_get_unless_zero(struct kref *kref) >> { >> - return atomic_add_unless(&kref->refcount, 1, 0); >> + return atomic_inc_not_zero(&kref->refcount); >> } >> #endif /* _KREF_H_ */ > ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-02-01 21:53 ` Jason A. Donenfeld @ 2016-06-29 22:52 ` Jason A. Donenfeld 2016-07-01 7:08 ` Thomas Hellstrom 0 siblings, 1 reply; 14+ messages in thread From: Jason A. Donenfeld @ 2016-06-29 22:52 UTC (permalink / raw) To: Thomas Hellstrom, Dave Airlie; +Cc: LKML, Paul McKenney This was positively reviewed by maintainers but never picked up. Can someone queue this for 4.7 or 4.8? Thanks, Jason On Mon, Feb 1, 2016 at 10:53 PM, Jason A. Donenfeld <Jason@zx2c4.com> wrote: > This was positively reviewed but never picked up. Can someone queue > this for rc3? > > Thanks, > Jason > > On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote: >> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> >> >> >> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: >>> On most platforms, there exists this ifdef: >>> >>> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) >>> >>> This makes this patch functionally useless. However, on PPC, there is >>> actually an explicit definition of atomic_inc_not_zero with its own >>> assembly that is slightly more optimized than atomic_add_unless. So, >>> this patch changes kref to use atomic_inc_not_zero instead, for PPC and >>> any future platforms that might provide an explicit implementation. >>> >>> This also puts this usage of kref more in line with a verbatim reading >>> of the examples in Paul McKenney's paper [1] in the section titled "2.4 >>> Atomic Counting With Check and Release Memory Barrier", which uses >>> atomic_inc_not_zero. >>> >>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= >>> >>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> >>> --- >>> include/linux/kref.h | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/include/linux/kref.h b/include/linux/kref.h >>> index 484604d..83d1f94 100644 >>> --- a/include/linux/kref.h >>> +++ b/include/linux/kref.h >>> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, >>> */ >>> static inline int __must_check kref_get_unless_zero(struct kref *kref) >>> { >>> - return atomic_add_unless(&kref->refcount, 1, 0); >>> + return atomic_inc_not_zero(&kref->refcount); >>> } >>> #endif /* _KREF_H_ */ >> ^ permalink raw reply [flat|nested] 14+ messages in thread
* Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-06-29 22:52 ` Jason A. Donenfeld @ 2016-07-01 7:08 ` Thomas Hellstrom 0 siblings, 0 replies; 14+ messages in thread From: Thomas Hellstrom @ 2016-07-01 7:08 UTC (permalink / raw) To: Dave Airlie; +Cc: Jason A. Donenfeld, LKML, Paul McKenney, dri-devel Dave, Since kref_get_unless_zero() was brought in by drm, could we add this to drm-next? Thanks, Thomas On 06/30/2016 12:52 AM, Jason A. Donenfeld wrote: > This was positively reviewed by maintainers but never picked up. Can > someone queue this for 4.7 or 4.8? > > Thanks, > Jason > > On Mon, Feb 1, 2016 at 10:53 PM, Jason A. Donenfeld <Jason@zx2c4.com> wrote: >> This was positively reviewed but never picked up. Can someone queue >> this for rc3? >> >> Thanks, >> Jason >> >> On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote: >>> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> >>> >>> >>> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: >>>> On most platforms, there exists this ifdef: >>>> >>>> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) >>>> >>>> This makes this patch functionally useless. However, on PPC, there is >>>> actually an explicit definition of atomic_inc_not_zero with its own >>>> assembly that is slightly more optimized than atomic_add_unless. So, >>>> this patch changes kref to use atomic_inc_not_zero instead, for PPC and >>>> any future platforms that might provide an explicit implementation. >>>> >>>> This also puts this usage of kref more in line with a verbatim reading >>>> of the examples in Paul McKenney's paper [1] in the section titled "2.4 >>>> Atomic Counting With Check and Release Memory Barrier", which uses >>>> atomic_inc_not_zero. >>>> >>>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= >>>> >>>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> >>>> --- >>>> include/linux/kref.h | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/include/linux/kref.h b/include/linux/kref.h >>>> index 484604d..83d1f94 100644 >>>> --- a/include/linux/kref.h >>>> +++ b/include/linux/kref.h >>>> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, >>>> */ >>>> static inline int __must_check kref_get_unless_zero(struct kref *kref) >>>> { >>>> - return atomic_add_unless(&kref->refcount, 1, 0); >>>> + return atomic_inc_not_zero(&kref->refcount); >>>> } >>>> #endif /* _KREF_H_ */ ^ permalink raw reply [flat|nested] 14+ messages in thread
* Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless @ 2016-07-01 7:08 ` Thomas Hellstrom 0 siblings, 0 replies; 14+ messages in thread From: Thomas Hellstrom @ 2016-07-01 7:08 UTC (permalink / raw) To: Dave Airlie; +Cc: Jason A. Donenfeld, Paul McKenney, LKML, dri-devel Dave, Since kref_get_unless_zero() was brought in by drm, could we add this to drm-next? Thanks, Thomas On 06/30/2016 12:52 AM, Jason A. Donenfeld wrote: > This was positively reviewed by maintainers but never picked up. Can > someone queue this for 4.7 or 4.8? > > Thanks, > Jason > > On Mon, Feb 1, 2016 at 10:53 PM, Jason A. Donenfeld <Jason@zx2c4.com> wrote: >> This was positively reviewed but never picked up. Can someone queue >> this for rc3? >> >> Thanks, >> Jason >> >> On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote: >>> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> >>> >>> >>> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: >>>> On most platforms, there exists this ifdef: >>>> >>>> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) >>>> >>>> This makes this patch functionally useless. However, on PPC, there is >>>> actually an explicit definition of atomic_inc_not_zero with its own >>>> assembly that is slightly more optimized than atomic_add_unless. So, >>>> this patch changes kref to use atomic_inc_not_zero instead, for PPC and >>>> any future platforms that might provide an explicit implementation. >>>> >>>> This also puts this usage of kref more in line with a verbatim reading >>>> of the examples in Paul McKenney's paper [1] in the section titled "2.4 >>>> Atomic Counting With Check and Release Memory Barrier", which uses >>>> atomic_inc_not_zero. >>>> >>>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= >>>> >>>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> >>>> --- >>>> include/linux/kref.h | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/include/linux/kref.h b/include/linux/kref.h >>>> index 484604d..83d1f94 100644 >>>> --- a/include/linux/kref.h >>>> +++ b/include/linux/kref.h >>>> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, >>>> */ >>>> static inline int __must_check kref_get_unless_zero(struct kref *kref) >>>> { >>>> - return atomic_add_unless(&kref->refcount, 1, 0); >>>> + return atomic_inc_not_zero(&kref->refcount); >>>> } >>>> #endif /* _KREF_H_ */ _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-07-01 7:08 ` Thomas Hellstrom @ 2016-07-12 12:28 ` Daniel Vetter -1 siblings, 0 replies; 14+ messages in thread From: Daniel Vetter @ 2016-07-12 12:28 UTC (permalink / raw) To: Thomas Hellstrom Cc: Dave Airlie, Jason A. Donenfeld, Paul McKenney, LKML, dri-devel On Fri, Jul 01, 2016 at 09:08:34AM +0200, Thomas Hellstrom wrote: > Dave, > > Since kref_get_unless_zero() was brought in by drm, could we add this to > drm-next? Sure can do, but I can't find the raw patch anywhere (I suck, I know). Care to resend? Thanks, Daniel > > Thanks, > Thomas > > > On 06/30/2016 12:52 AM, Jason A. Donenfeld wrote: > > This was positively reviewed by maintainers but never picked up. Can > > someone queue this for 4.7 or 4.8? > > > > Thanks, > > Jason > > > > On Mon, Feb 1, 2016 at 10:53 PM, Jason A. Donenfeld <Jason@zx2c4.com> wrote: > >> This was positively reviewed but never picked up. Can someone queue > >> this for rc3? > >> > >> Thanks, > >> Jason > >> > >> On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote: > >>> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> > >>> > >>> > >>> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: > >>>> On most platforms, there exists this ifdef: > >>>> > >>>> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) > >>>> > >>>> This makes this patch functionally useless. However, on PPC, there is > >>>> actually an explicit definition of atomic_inc_not_zero with its own > >>>> assembly that is slightly more optimized than atomic_add_unless. So, > >>>> this patch changes kref to use atomic_inc_not_zero instead, for PPC and > >>>> any future platforms that might provide an explicit implementation. > >>>> > >>>> This also puts this usage of kref more in line with a verbatim reading > >>>> of the examples in Paul McKenney's paper [1] in the section titled "2.4 > >>>> Atomic Counting With Check and Release Memory Barrier", which uses > >>>> atomic_inc_not_zero. > >>>> > >>>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= > >>>> > >>>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > >>>> --- > >>>> include/linux/kref.h | 2 +- > >>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>> > >>>> diff --git a/include/linux/kref.h b/include/linux/kref.h > >>>> index 484604d..83d1f94 100644 > >>>> --- a/include/linux/kref.h > >>>> +++ b/include/linux/kref.h > >>>> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, > >>>> */ > >>>> static inline int __must_check kref_get_unless_zero(struct kref *kref) > >>>> { > >>>> - return atomic_add_unless(&kref->refcount, 1, 0); > >>>> + return atomic_inc_not_zero(&kref->refcount); > >>>> } > >>>> #endif /* _KREF_H_ */ > > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless @ 2016-07-12 12:28 ` Daniel Vetter 0 siblings, 0 replies; 14+ messages in thread From: Daniel Vetter @ 2016-07-12 12:28 UTC (permalink / raw) To: Thomas Hellstrom Cc: Dave Airlie, Jason A. Donenfeld, Paul McKenney, LKML, dri-devel On Fri, Jul 01, 2016 at 09:08:34AM +0200, Thomas Hellstrom wrote: > Dave, > > Since kref_get_unless_zero() was brought in by drm, could we add this to > drm-next? Sure can do, but I can't find the raw patch anywhere (I suck, I know). Care to resend? Thanks, Daniel > > Thanks, > Thomas > > > On 06/30/2016 12:52 AM, Jason A. Donenfeld wrote: > > This was positively reviewed by maintainers but never picked up. Can > > someone queue this for 4.7 or 4.8? > > > > Thanks, > > Jason > > > > On Mon, Feb 1, 2016 at 10:53 PM, Jason A. Donenfeld <Jason@zx2c4.com> wrote: > >> This was positively reviewed but never picked up. Can someone queue > >> this for rc3? > >> > >> Thanks, > >> Jason > >> > >> On Sun, Oct 11, 2015 at 9:59 PM, Thomas Hellstrom <thellstrom@vmware.com> wrote: > >>> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> > >>> > >>> > >>> On 10/10/2015 12:56 PM, Jason A. Donenfeld wrote: > >>>> On most platforms, there exists this ifdef: > >>>> > >>>> #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) > >>>> > >>>> This makes this patch functionally useless. However, on PPC, there is > >>>> actually an explicit definition of atomic_inc_not_zero with its own > >>>> assembly that is slightly more optimized than atomic_add_unless. So, > >>>> this patch changes kref to use atomic_inc_not_zero instead, for PPC and > >>>> any future platforms that might provide an explicit implementation. > >>>> > >>>> This also puts this usage of kref more in line with a verbatim reading > >>>> of the examples in Paul McKenney's paper [1] in the section titled "2.4 > >>>> Atomic Counting With Check and Release Memory Barrier", which uses > >>>> atomic_inc_not_zero. > >>>> > >>>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= > >>>> > >>>> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > >>>> --- > >>>> include/linux/kref.h | 2 +- > >>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>> > >>>> diff --git a/include/linux/kref.h b/include/linux/kref.h > >>>> index 484604d..83d1f94 100644 > >>>> --- a/include/linux/kref.h > >>>> +++ b/include/linux/kref.h > >>>> @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, > >>>> */ > >>>> static inline int __must_check kref_get_unless_zero(struct kref *kref) > >>>> { > >>>> - return atomic_add_unless(&kref->refcount, 1, 0); > >>>> + return atomic_inc_not_zero(&kref->refcount); > >>>> } > >>>> #endif /* _KREF_H_ */ > > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: Patch for drm-next WAS Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-07-12 12:28 ` Daniel Vetter (?) @ 2016-12-15 4:59 ` Jason A. Donenfeld -1 siblings, 0 replies; 14+ messages in thread From: Jason A. Donenfeld @ 2016-12-15 4:59 UTC (permalink / raw) To: Thomas Hellstrom, Dave Airlie, Jason A. Donenfeld, Paul McKenney, LKML, dri-devel On Tue, Jul 12, 2016 at 2:28 PM, Daniel Vetter <daniel@ffwll.ch> wrote: > Sure can do, but I can't find the raw patch anywhere (I suck, I know). > Care to resend? Hey sorry I missed this email requesting the actual patch. I reposted it here: https://lkml.org/lkml/2016/12/14/814 ^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-07-12 12:28 ` Daniel Vetter (?) (?) @ 2016-12-15 5:01 ` Jason A. Donenfeld 2016-12-16 7:33 ` Daniel Vetter -1 siblings, 1 reply; 14+ messages in thread From: Jason A. Donenfeld @ 2016-12-15 5:01 UTC (permalink / raw) To: Thomas Hellstrom, dri-devel; +Cc: Jason A. Donenfeld On most platforms, there exists this ifdef: #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) This makes this patch functionally useless. However, on PPC, there is actually an explicit definition of atomic_inc_not_zero with its own assembly that is slightly more optimized than atomic_add_unless. So, this patch changes kref to use atomic_inc_not_zero instead, for PPC and any future platforms that might provide an explicit implementation. This also puts this usage of kref more in line with a verbatim reading of the examples in Paul McKenney's paper [1] in the section titled "2.4 Atomic Counting With Check and Release Memory Barrier", which uses atomic_inc_not_zero. [1] http://open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2167.pdf Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> --- This was reviewed favorably 14 months ago but never picked up. I'm resubmitting it now in hopes that you can finally queue it up for 4.10. include/linux/kref.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/kref.h b/include/linux/kref.h index e15828fd71f1..62f0a84ae94e 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -133,6 +133,6 @@ static inline int kref_put_mutex(struct kref *kref, */ static inline int __must_check kref_get_unless_zero(struct kref *kref) { - return atomic_add_unless(&kref->refcount, 1, 0); + return atomic_inc_not_zero(&kref->refcount); } #endif /* _KREF_H_ */ -- 2.11.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-12-15 5:01 ` Jason A. Donenfeld @ 2016-12-16 7:33 ` Daniel Vetter 0 siblings, 0 replies; 14+ messages in thread From: Daniel Vetter @ 2016-12-16 7:33 UTC (permalink / raw) To: Jason A. Donenfeld; +Cc: Thomas Hellstrom, dri-devel On Thu, Dec 15, 2016 at 06:01:10AM +0100, Jason A. Donenfeld wrote: > On most platforms, there exists this ifdef: > > #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) > > This makes this patch functionally useless. However, on PPC, there is > actually an explicit definition of atomic_inc_not_zero with its own > assembly that is slightly more optimized than atomic_add_unless. So, > this patch changes kref to use atomic_inc_not_zero instead, for PPC and > any future platforms that might provide an explicit implementation. > > This also puts this usage of kref more in line with a verbatim reading > of the examples in Paul McKenney's paper [1] in the section titled "2.4 > Atomic Counting With Check and Release Memory Barrier", which uses > atomic_inc_not_zero. > > [1] http://open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2167.pdf > > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> Applied to drm-misc, but for 4.11 since 4.10 is bugfixes only already. Thanks, Daniel > --- > This was reviewed favorably 14 months ago but never picked up. > I'm resubmitting it now in hopes that you can finally queue it > up for 4.10. > > include/linux/kref.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/kref.h b/include/linux/kref.h > index e15828fd71f1..62f0a84ae94e 100644 > --- a/include/linux/kref.h > +++ b/include/linux/kref.h > @@ -133,6 +133,6 @@ static inline int kref_put_mutex(struct kref *kref, > */ > static inline int __must_check kref_get_unless_zero(struct kref *kref) > { > - return atomic_add_unless(&kref->refcount, 1, 0); > + return atomic_inc_not_zero(&kref->refcount); > } > #endif /* _KREF_H_ */ > -- > 2.11.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2015-10-11 19:59 ` Thomas Hellstrom 2016-02-01 21:53 ` Jason A. Donenfeld @ 2016-12-15 4:58 ` Jason A. Donenfeld 2016-12-15 8:51 ` Christoph Hellwig 1 sibling, 1 reply; 14+ messages in thread From: Jason A. Donenfeld @ 2016-12-15 4:58 UTC (permalink / raw) To: Dave Airlie, linux-kernel, Thomas Hellstrom; +Cc: Jason A. Donenfeld On most platforms, there exists this ifdef: #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) This makes this patch functionally useless. However, on PPC, there is actually an explicit definition of atomic_inc_not_zero with its own assembly that is slightly more optimized than atomic_add_unless. So, this patch changes kref to use atomic_inc_not_zero instead, for PPC and any future platforms that might provide an explicit implementation. This also puts this usage of kref more in line with a verbatim reading of the examples in Paul McKenney's paper [1] in the section titled "2.4 Atomic Counting With Check and Release Memory Barrier", which uses atomic_inc_not_zero. [1] http://open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2167.pdf Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> --- This was reviewed favorably 14 months ago but never picked up. I'm resubmitting it now in hopes that you can finally queue it up for 4.10. include/linux/kref.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/kref.h b/include/linux/kref.h index e15828fd71f1..62f0a84ae94e 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -133,6 +133,6 @@ static inline int kref_put_mutex(struct kref *kref, */ static inline int __must_check kref_get_unless_zero(struct kref *kref) { - return atomic_add_unless(&kref->refcount, 1, 0); + return atomic_inc_not_zero(&kref->refcount); } #endif /* _KREF_H_ */ -- 2.11.0 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2016-12-15 4:58 ` Jason A. Donenfeld @ 2016-12-15 8:51 ` Christoph Hellwig 0 siblings, 0 replies; 14+ messages in thread From: Christoph Hellwig @ 2016-12-15 8:51 UTC (permalink / raw) To: Jason A. Donenfeld; +Cc: Dave Airlie, linux-kernel, Thomas Hellstrom It's also way easier to read using atomic_inc_not_zero.. Reviewed-by: Christoph Hellwig <hch@lst.de> Not sure you're sending this to the right maintainers, though. You probably want to include Greg. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Fwd: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless 2015-10-10 10:56 [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless Jason A. Donenfeld 2015-10-11 19:59 ` Thomas Hellstrom @ 2016-08-10 12:24 ` Thomas Hellstrom 1 sibling, 0 replies; 14+ messages in thread From: Thomas Hellstrom @ 2016-08-10 12:24 UTC (permalink / raw) To: Daniel Vetter; +Cc: dri-devel By request forwarded patch This is also Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> /Thomas -------- Forwarded Message -------- Subject: [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless Date: Sat, 10 Oct 2015 12:56:34 +0200 From: Jason A. Donenfeld <Jason@zx2c4.com> To: Dave Airlie <airlied@redhat.com>, Thomas Hellstrom <thellstrom@vmware.com>, linux-kernel@vger.kernel.org CC: Jason A. Donenfeld <Jason@zx2c4.com> On most platforms, there exists this ifdef: #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) This makes this patch functionally useless. However, on PPC, there is actually an explicit definition of atomic_inc_not_zero with its own assembly that is slightly more optimized than atomic_add_unless. So, this patch changes kref to use atomic_inc_not_zero instead, for PPC and any future platforms that might provide an explicit implementation. This also puts this usage of kref more in line with a verbatim reading of the examples in Paul McKenney's paper [1] in the section titled "2.4 Atomic Counting With Check and Release Memory Barrier", which uses atomic_inc_not_zero. [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__open-2Dstd.org_jtc1_sc22_wg21_docs_papers_2007_n2167.pdf&d=BQIBAg&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=vpukPkBtpoNQp2IUKuFviOmPNYWVKmen3Jeeu55zmEA&m=z5Nd9sYiJMKiphNjyZp6XT5CbayXMBlcb903f260pDY&s=HEHX3CuXRs2GRRQWuC4Vef6iJMwdilKVRkiZgJpjEpA&e= Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- include/linux/kref.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/kref.h b/include/linux/kref.h index 484604d..83d1f94 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -166,6 +166,6 @@ static inline int kref_put_mutex(struct kref *kref, */ static inline int __must_check kref_get_unless_zero(struct kref *kref) { - return atomic_add_unless(&kref->refcount, 1, 0); + return atomic_inc_not_zero(&kref->refcount); } #endif /* _KREF_H_ */ -- 2.6.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel ^ permalink raw reply related [flat|nested] 14+ messages in thread
end of thread, other threads:[~2016-12-16 7:33 UTC | newest] Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-10-10 10:56 [PATCH] kref: prefer atomic_inc_not_zero to atomic_add_unless Jason A. Donenfeld 2015-10-11 19:59 ` Thomas Hellstrom 2016-02-01 21:53 ` Jason A. Donenfeld 2016-06-29 22:52 ` Jason A. Donenfeld 2016-07-01 7:08 ` Patch for drm-next WAS " Thomas Hellstrom 2016-07-01 7:08 ` Thomas Hellstrom 2016-07-12 12:28 ` Daniel Vetter 2016-07-12 12:28 ` Daniel Vetter 2016-12-15 4:59 ` Jason A. Donenfeld 2016-12-15 5:01 ` Jason A. Donenfeld 2016-12-16 7:33 ` Daniel Vetter 2016-12-15 4:58 ` Jason A. Donenfeld 2016-12-15 8:51 ` Christoph Hellwig 2016-08-10 12:24 ` Fwd: " Thomas Hellstrom
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