On Sat, Nov 28, 2020 at 03:32:59PM -0500, Paul Gortmaker wrote: > It appears the Compaq link moved to a machine at HP for a while > after the merger of the two, but that doesn't work either. A search > of HP for "wiz_2637" (w and w/o html suffix) comes up empty. > > Since the references aren't critical to the documents we remove them. > > Also, the lkml.kernel.org/g links have been broken for ages, so replace > them with lore.kernel.org/r links - standardize on lore for all links too. > > Note that we put off fixing these 4y ago - presumably thinking that a > treewide fixup was pending. Probably safe to go fix the RCU ones now. > > https://lore.kernel.org/r/20160915144926.GD10850@xxxxxxxxxxxxxxxxxx/ > > Cc: Michael Opdenacker <michael.opdenacker@xxxxxxxxxxxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> Queued for further review, thank you! Thanx, Paul > --- > > [v2: 2nd dead Alpha link found; also fixup the lkml --> lore links.] > > .../RCU/Design/Requirements/Requirements.rst | 23 +++++++++---------- > Documentation/RCU/checklist.rst | 8 +++---- > 2 files changed, 14 insertions(+), 17 deletions(-) > > diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst > index 2dce79dd0eaa..4ff0f4506fbf 100644 > --- a/Documentation/RCU/Design/Requirements/Requirements.rst > +++ b/Documentation/RCU/Design/Requirements/Requirements.rst > @@ -321,11 +321,10 @@ do_something_gp_buggy() below: > 12 } > > However, this temptation must be resisted because there are a > -surprisingly large number of ways that the compiler (to say nothing of > -`DEC Alpha CPUs <https://h71000.www7.hp.com/wizard/wiz_2637.html>`__) > -can trip this code up. For but one example, if the compiler were short > -of registers, it might choose to refetch from ``gp`` rather than keeping > -a separate copy in ``p`` as follows: > +surprisingly large number of ways that the compiler (or weak ordering > +CPUs like the DEC Alpha) can trip this code up. For but one example, if > +the compiler were short of registers, it might choose to refetch from > +``gp`` rather than keeping a separate copy in ``p`` as follows: > > :: > > @@ -1183,7 +1182,7 @@ costs have plummeted. However, as I learned from Matt Mackall's > `bloatwatch <http://elinux.org/Linux_Tiny-FAQ>`__ efforts, memory > footprint is critically important on single-CPU systems with > non-preemptible (``CONFIG_PREEMPT=n``) kernels, and thus `tiny > -RCU <https://lkml.kernel.org/g/20090113221724.GA15307@xxxxxxxxxxxxxxxxxx>`__ > +RCU <https://lore.kernel.org/r/20090113221724.GA15307@xxxxxxxxxxxxxxxxxx>`__ > was born. Josh Triplett has since taken over the small-memory banner > with his `Linux kernel tinification <https://tiny.wiki.kernel.org/>`__ > project, which resulted in `SRCU <#Sleepable%20RCU>`__ becoming optional > @@ -1624,7 +1623,7 @@ against mishaps and misuse: > init_rcu_head() and cleaned up with destroy_rcu_head(). > Mathieu Desnoyers made me aware of this requirement, and also > supplied the needed > - `patch <https://lkml.kernel.org/g/20100319013024.GA28456@Krystal>`__. > + `patch <https://lore.kernel.org/r/20100319013024.GA28456@Krystal>`__. > #. An infinite loop in an RCU read-side critical section will eventually > trigger an RCU CPU stall warning splat, with the duration of > “eventually” being controlled by the ``RCU_CPU_STALL_TIMEOUT`` > @@ -1716,7 +1715,7 @@ requires almost all of them be hidden behind a ``CONFIG_RCU_EXPERT`` > > This all should be quite obvious, but the fact remains that Linus > Torvalds recently had to > -`remind <https://lkml.kernel.org/g/CA+55aFy4wcCwaL4okTs8wXhGZ5h-ibecy_Meg9C4MNQrUnwMcg@xxxxxxxxxxxxxx>`__ > +`remind <https://lore.kernel.org/r/CA+55aFy4wcCwaL4okTs8wXhGZ5h-ibecy_Meg9C4MNQrUnwMcg@xxxxxxxxxxxxxx>`__ > me of this requirement. > > Firmware Interface > @@ -1837,9 +1836,9 @@ NMI handlers. > > The name notwithstanding, some Linux-kernel architectures can have > nested NMIs, which RCU must handle correctly. Andy Lutomirski `surprised > -me <https://lkml.kernel.org/r/CALCETrXLq1y7e_dKFPgou-FKHB6Pu-r8+t-6Ds+8=va7anBWDA@xxxxxxxxxxxxxx>`__ > +me <https://lore.kernel.org/r/CALCETrXLq1y7e_dKFPgou-FKHB6Pu-r8+t-6Ds+8=va7anBWDA@xxxxxxxxxxxxxx>`__ > with this requirement; he also kindly surprised me with `an > -algorithm <https://lkml.kernel.org/r/CALCETrXSY9JpW3uE6H8WYk81sg56qasA2aqmjMPsq5dOtzso=g@xxxxxxxxxxxxxx>`__ > +algorithm <https://lore.kernel.org/r/CALCETrXSY9JpW3uE6H8WYk81sg56qasA2aqmjMPsq5dOtzso=g@xxxxxxxxxxxxxx>`__ > that meets this requirement. > > Furthermore, NMI handlers can be interrupted by what appear to RCU to be > @@ -2264,7 +2263,7 @@ more extreme measures. Returning to the ``page`` structure, the > ``rcu_head`` field shares storage with a great many other structures > that are used at various points in the corresponding page's lifetime. In > order to correctly resolve certain `race > -conditions <https://lkml.kernel.org/g/1439976106-137226-1-git-send-email-kirill.shutemov@xxxxxxxxxxxxxxx>`__, > +conditions <https://lore.kernel.org/r/1439976106-137226-1-git-send-email-kirill.shutemov@xxxxxxxxxxxxxxx>`__, > the Linux kernel's memory-management subsystem needs a particular bit to > remain zero during all phases of grace-period processing, and that bit > happens to map to the bottom bit of the ``rcu_head`` structure's > @@ -2328,7 +2327,7 @@ preempted. This requirement made its presence known after users made it > clear that an earlier `real-time > patch <https://lwn.net/Articles/107930/>`__ did not meet their needs, in > conjunction with some `RCU > -issues <https://lkml.kernel.org/g/20050318002026.GA2693@xxxxxxxxxx>`__ > +issues <https://lore.kernel.org/r/20050318002026.GA2693@xxxxxxxxxx>`__ > encountered by a very early version of the -rt patchset. > > In addition, RCU must make do with a sub-100-microsecond real-time > diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst > index bb7128eb322e..2d1dc1deffc9 100644 > --- a/Documentation/RCU/checklist.rst > +++ b/Documentation/RCU/checklist.rst > @@ -70,7 +70,7 @@ over a rather long period of time, but improvements are always welcome! > is less readable and prevents lockdep from detecting locking issues. > > Letting RCU-protected pointers "leak" out of an RCU read-side > - critical section is every bid as bad as letting them leak out > + critical section is every bit as bad as letting them leak out > from under a lock. Unless, of course, you have arranged some > other means of protection, such as a lock or a reference count > -before- letting them out of the RCU read-side critical section. > @@ -129,9 +129,7 @@ over a rather long period of time, but improvements are always welcome! > accesses. The rcu_dereference() primitive ensures that > the CPU picks up the pointer before it picks up the data > that the pointer points to. This really is necessary > - on Alpha CPUs. If you don't believe me, see: > - > - http://www.openvms.compaq.com/wizard/wiz_2637.html > + on Alpha CPUs. > > The rcu_dereference() primitive is also an excellent > documentation aid, letting the person reading the > @@ -216,7 +214,7 @@ over a rather long period of time, but improvements are always welcome! > 7. As of v4.20, a given kernel implements only one RCU flavor, > which is RCU-sched for PREEMPT=n and RCU-preempt for PREEMPT=y. > If the updater uses call_rcu() or synchronize_rcu(), > - then the corresponding readers my use rcu_read_lock() and > + then the corresponding readers may use rcu_read_lock() and > rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(), > or any pair of primitives that disables and re-enables preemption, > for example, rcu_read_lock_sched() and rcu_read_unlock_sched(). > -- > 2.17.1 >
