IRC.

24 files changed, 864 insertions, 15 deletions

diff --git a/open_issues/64-bit_port.mdwn b/open_issues/64-bit_port.mdwn
new file mode 100644
index 00000000..797d540f
--- /dev/null
+++ b/open_issues/64-bit_port.mdwn
@@ -0,0 +1,36 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_gnumach open_issue_mig]]
+
+IRC, freenode, #hurd, 2011-10-16:
+
+    <youpi> it'd be really good to have a 64bit kernel, no need to care about
+      addressing space :)
+    <braunr> yes a 64 bits kernel would be nice
+    <braunr> i guess it wouldn't be too hard to have a special mach kernel for
+      64 bits processors, but 32 bits userland only
+    <youpi> well, it means tinkering with mig
+    <braunr> like old sparc systems :p
+    <youpi> to build the 32bit interface, not the 64bit one
+    <braunr> ah yes
+    <braunr> hm
+    <braunr> i'm not sure
+    <braunr> mig would assume a 32 bits kernel, like now
+    <youpi> and you'll have all kinds of discrepancies in vm_size_t & such
+    <braunr> yes
+    <braunr> the 64 bits type should be completely internal
+    <braunr> types*
+    <braunr> but it would be far less work than changing all the userspace bits
+      for 64 bit (ofc we'll do that some day but in the meanwhile ..)
+    <youpi> yes
+    <youpi> and it'd boost userland addrespace to 4GiB
+    <braunr> yes
+    <youpi> leaving time for a 64bit userland :)
diff --git a/open_issues/anatomy_of_a_hurd_system.mdwn b/open_issues/anatomy_of_a_hurd_system.mdwn
index 64af3d00..46526641 100644
--- a/open_issues/anatomy_of_a_hurd_system.mdwn
+++ b/open_issues/anatomy_of_a_hurd_system.mdwn
@@ -13,7 +13,7 @@ License|/fdl]]."]]"""]]
 A bunch of this should also be covered in other (introductionary) material,
 like Bushnell's Hurd paper.  All this should be unfied and streamlined.
 
-IRC, freenode, #hurd, 2011-03-08
+IRC, freenode, #hurd, 2011-03-08:
 
     <foocraft> I've a question on what are the "units" in the hurd project, if
       you were to divide them into units if they aren't, and what are the
@@ -40,7 +40,7 @@ IRC, freenode, #hurd, 2011-03-08
 
 ---
 
-IRC, freenode, #hurd, 2011-03-12
+IRC, freenode, #hurd, 2011-03-12:
 
     <dEhiN> when mach first starts up, does it have some basic i/o or fs
       functionality built into it to start up the initial hurd translators?
@@ -86,3 +86,13 @@ RPC stubs.
 ---
 
 More stuff like [[hurd/IO_path]].
+
+--
+
+IRC, freenode, #hurd, 2011-10-18:
+
+    <frhodes> what happens @ boot. and which translators are started in what
+      order?
+    <antrik> short version: grub loads mach, ext2, and ld.so/exec; mach starts
+      ext2; ext2 starts exec; ext2 execs a few other servers; ext2 execs
+      init. from there on, it's just standard UNIX stuff
diff --git a/open_issues/benefits_of_a_native_hurd_implementation.mdwn b/open_issues/benefits_of_a_native_hurd_implementation.mdwn
index d796bf6b..afdcfb73 100644
--- a/open_issues/benefits_of_a_native_hurd_implementation.mdwn
+++ b/open_issues/benefits_of_a_native_hurd_implementation.mdwn
@@ -27,7 +27,7 @@ IRC, #hurd, August / September 2010
       runs Linux in user space (just flip the two) for the drivers
     <marcusb> ArneBab: that is what the L4 people did with the DDE
 
-([[DDE]])
+[[/DDE]].
 
     <marcusb> ArneBab: so, with these different cuts, there are different
       opportunities. on the one end, you can run Linux as normal and get some
diff --git a/open_issues/bsd_compatibility.mdwn b/open_issues/bsd_compatibility.mdwn
new file mode 100644
index 00000000..5c916908
--- /dev/null
+++ b/open_issues/bsd_compatibility.mdwn
@@ -0,0 +1,34 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_documentation]]
+
+IRC, freenode, #hurd, 2011-10-12:
+
+    <pinotree> hm, why our sys/param.h #define's BSD?
+    <braunr> pinotree: because we're evil
+    <pinotree> is that correct?
+    <pinotree> (the define, not the evilness)
+    <braunr> pinotree: i think it's because the Hurd is closer to the BSD
+      interfaces, probably because of Mach (which is itself derived from
+      BSD4.2)
+    <pinotree> braunr: but mach being bsd-ish won't make the userland (glibc)
+      interfaces bsd-ish, will it?
+    <braunr> pinotree: no
+    <pinotree> braunr: so...? :)
+    <braunr> pinotree: i guesse there are bsdisms in the glibc hurd specific
+      code, possibly because of mach
+    <braunr> or they used to be bsdisms, before being standardized
+    <braunr> e.g. mmap
+    <pinotree> braunr: hrmm...
+    <antrik> braunr: the BSDisms are there on purpose... Hurd was originally
+      even meant to be binary-compatible with BSD
+    <antrik> nothing to do with Mach really
+    <braunr> antrik: ok
diff --git a/open_issues/dde.mdwn b/open_issues/dde.mdwn
index ef319a5c..9e2ec742 100644
--- a/open_issues/dde.mdwn
+++ b/open_issues/dde.mdwn
@@ -1,4 +1,4 @@
-[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
+[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]]
 
 [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
 id="license" text="Permission is granted to copy, distribute and/or modify this
@@ -8,4 +8,25 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
 is included in the section entitled [[GNU Free Documentation
 License|/fdl]]."]]"""]]
 
-[[!meta redir=/dde]]
+[[General Information|/dde]].
+
+
+# IRC, freenode, #hurd, 2011-10-18
+
+[[!tag open_issue_hurd]]
+
+    [DDE crash, or similar]
+    <youpi> it's fake_local_irq_disable_flags(), then raw_local_irq_disable(),
+      then raw_local_irq_restore(), which *does not* release the cli_lock
+    <youpi> the "prove it" comment is (as I expected) completely wrong
+    <youpi> npnth: http://paste.debian.net/137784/
+
+[[137784]]
+
+    <youpi> could you try this patch ?
+    <youpi> (I've not even tried to build it)
+    <npnth> youpi: speaking of which, it still seems to hang :/  I'll 1) double
+      check it applied correctly and 2) get a gdb output if it did
+    <youpi> npnth: could you add printing the value of unlock_refcnt?
+    <youpi> so we can check what's happening
+    <npnth> unlock_refcnt is at 0, interesting
diff --git a/open_issues/dde/137784 b/open_issues/dde/137784
new file mode 100644
index 00000000..1529465b
--- /dev/null
+++ b/open_issues/dde/137784
@@ -0,0 +1,43 @@
+diff --git a/libdde_linux26/lib/src/arch/l4/cli_sti.c b/libdde_linux26/lib/src/arch/l4/cli_sti.c
+index 051f259..6a8c460 100644
+--- a/libdde_linux26/lib/src/arch/l4/cli_sti.c
++++ b/libdde_linux26/lib/src/arch/l4/cli_sti.c
+@@ -4,6 +4,8 @@
+ 
+ /* IRQ lock reference counter */
+ static atomic_t      _refcnt   = ATOMIC_INIT(0);
++/* Refcnt value at which unlocking the cli_lock (it's not always 0) */
++static int unlock_refcnt;
+ static ddekit_lock_t cli_lock;
+ 
+ /* Check whether IRQs are currently disabled.
+@@ -57,9 +59,6 @@ void fake_local_irq_restore(unsigned long flags)
+ /* Store the current flags state.
+  *
+  * This is done by returning the current refcnt.
+- *
+- * XXX: Up to now, flags was always 0 at this point and
+- *      I assume that this is always the case. Prove?
+  */
+ unsigned long __raw_local_save_flags(void)
+ {
+@@ -82,7 +81,7 @@ void raw_local_irq_restore(unsigned long flags)
+ {
+ 	Assert(cli_lock != NULL);
+ 	atomic_set(&_refcnt, flags);
+-	if (flags == 0)
++	if (flags == unlock_refcnt)
+ 		ddekit_lock_unlock(&cli_lock);
+ }
+ 
+@@ -95,7 +94,9 @@ void raw_local_irq_disable(void)
+ 	if (cli_lock == NULL)
+ 		ddekit_lock_init_unlocked(&cli_lock);
+ 
+-	nested_lock(cli_lock);
++	if (nested_lock(cli_lock))
++		/* Tell the corresponding restorer to release cli_lock */
++		unlock_refcnt = atomic_read(&_refcnt);
+ 	atomic_inc(&_refcnt);
+ }
+ 
diff --git a/open_issues/dev_zero_size.mdwn b/open_issues/dev_zero_size.mdwn
new file mode 100644
index 00000000..20c5147e
--- /dev/null
+++ b/open_issues/dev_zero_size.mdwn
@@ -0,0 +1,21 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_hurd]]
+
+IRC, freenode, #hurd, 2011-10-18:
+
+    <pinotree> i guess it is not normal for /dev/zero have a size of
+      (size_t)-1, no?
+    <pinotree> (it isn't (size_t)-1, but (long long)-1)
+
+2011-10-19:
+
+    <pinotree> see the size you get with `stat /dev/zero`
diff --git a/open_issues/device_drivers_and_io_systems.mdwn b/open_issues/device_drivers_and_io_systems.mdwn
index ce50d93e..5bda0213 100644
--- a/open_issues/device_drivers_and_io_systems.mdwn
+++ b/open_issues/device_drivers_and_io_systems.mdwn
@@ -1,4 +1,4 @@
-[[!meta copyright="Copyright © 2009 Free Software Foundation, Inc."]]
+[[!meta copyright="Copyright © 2009, 2011 Free Software Foundation, Inc."]]
 
 [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
 id="license" text="Permission is granted to copy, distribute and/or modify this
@@ -68,7 +68,7 @@ Also see [[user-space device drivers]].
 
 # External Projects
 
-  * [[DDE]]
+  * [[/DDE]]
 
   * [Building Linux Device Drivers on
     FreeBSD](http://info.iet.unipi.it/~luigi/FreeBSD/linux_bsd_kld.html)
diff --git a/open_issues/fifo_O_RDWR.mdwn b/open_issues/fifo_O_RDWR.mdwn
new file mode 100644
index 00000000..730e5c6f
--- /dev/null
+++ b/open_issues/fifo_O_RDWR.mdwn
@@ -0,0 +1,25 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!meta title="fifo O_RDWR"]]
+
+[[!tag open_issue_hurd]]
+
+[[!debbug 646016]]
+
+IRC, OFTC, #debian-hurd, 2011-10-19:
+
+    <tschwinge> pinotree: Nice!  And that open(FIFO, O_RDWR) hanging issue may
+      warrant investigation on the Hurd side, too -- if the other systems
+      behave differently, we should probably have convincing reasons for our
+      behavior.
+    <pinotree> i gue somebody working on hurd never cared about that case - i
+      guess it falls back to one of O_RDONLY or O_WRONLY
+    <pinotree> *guess
diff --git a/open_issues/glibc.mdwn b/open_issues/glibc.mdwn
index e48dde9c..d3f88673 100644
--- a/open_issues/glibc.mdwn
+++ b/open_issues/glibc.mdwn
@@ -59,6 +59,8 @@ Last reviewed up to the [[Git mirror's 187da0aedcd9d0a2fb34477bef41549681ba1273
 
       * `TLS_INIT_TP_EXPENSIVE` is unused; Hurd def. can be removed.
 
+  * [[t/tls-threadvar]]
+
   * t/verify.h
 
     People didn't like this too much.
diff --git a/open_issues/glibc/t/tls-threadvar.mdwn b/open_issues/glibc/t/tls-threadvar.mdwn
new file mode 100644
index 00000000..f6a81590
--- /dev/null
+++ b/open_issues/glibc/t/tls-threadvar.mdwn
@@ -0,0 +1,24 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_glibc open_issue_libpthread]]
+
+IRC, freenode, #hurd, 2011-10-23:
+
+    <tschwinge> youpi: If we want to replace threadvars with TLS, there is one
+      problem: the threadvars interface is publically exported:
+      /usr/include/hurd/threadvar.h.
+    <tschwinge> youpi: But I am somewhat inclined to say that the only user of
+      this is libthreads/libpthread.  Do you think differently?
+    <youpi> tschwinge: that's very probable
+    <youpi> so I think we can just drop it
+    <youpi> (people should use TLS anyway)
+
+[[libpthread_set_stack_size]].
diff --git a/open_issues/gnumach_memory_management.mdwn b/open_issues/gnumach_memory_management.mdwn
index fb3d6895..9a4418c1 100644
--- a/open_issues/gnumach_memory_management.mdwn
+++ b/open_issues/gnumach_memory_management.mdwn
@@ -1777,3 +1777,36 @@ There is a [[!FF_project 266]][[!tag bounty]] on this task.
     <braunr> an idea for when there's time
     <braunr> eh
     <antrik> hehe :-)
+
+
+# IRC, freenode, #hurd, 2011-10-13
+
+    <braunr> mcsim: what's the current state of your gnumach branch ?
+    <mcsim> I've merged it with master in September
+    <braunr> yes i've seen that, but does it build and run fine ?
+    <mcsim> I've tested it on gnumach from debian repository, but for building
+      I had to make additional change in device/ramdisk.c, as I mentioned.
+    <braunr> mcsim: why ?
+    <mcsim> And it runs fine for me.
+    <braunr> mcsim: why did you need to make other changes ?
+    <mcsim> because there is a patch which comes with from-debian-repository
+      kernel and it addes some code, where I have to make changes. Earlier
+      kernel_map was a pointer to structure, but I change that and now
+      kernel_map is structure. So handling to it should be by taking the
+      address (&kernel_map)
+    <braunr> why did you do that ?
+    <braunr> or put it another way: what made you do that type change on
+      kernel_map ?
+    <mcsim> Earlier memory for kernel_map was allocating with zalloc. But now
+      salloc can't allocate memory before it's initialisation
+    <braunr> that's not a good reason
+    <braunr> a simple workaround for your problem is this :
+    <braunr> static struct vm_map kernel_map_store;
+    <braunr> vm_map_t kernel_map = &kernel_map_store;
+    <mcsim> braunr: Ok. I'll correct this.
+
+
+# IRC, freenode, #hurd, 2011-11-01
+
+    <braunr> etenil: but mcsim's work is, for one, useful because the allocator
+      code is much clearer, adds some debugging support, and is smp-ready
diff --git a/open_issues/gnumach_memory_management_2.mdwn b/open_issues/gnumach_memory_management_2.mdwn
new file mode 100644
index 00000000..64aae2a4
--- /dev/null
+++ b/open_issues/gnumach_memory_management_2.mdwn
@@ -0,0 +1,246 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_gnumach]]
+
+IRC, freenode, #hurd, 2011-10-16:
+
+    <youpi> braunr: I realize that kmem_alloc_wired maps the allocated pages in
+      the kernel map
+    <youpi> it's a bit of a waste when my allocation is exactly a page size
+    <youpi> is there a proper page allocation which would simply return its
+      physical address?
+    <youpi> pages returned by vm_page_grab  may get swapped out, right?
+    <youpi> so could it be a matter of calling vm_page_alloc then vm_page_wire
+      (with lock_queues held) ?
+    <youpi> s/alloc/grab/
+    <braunr> vm_page_grab() is only used at boot iirc
+    <braunr> youpi: mapping allocated memory in the kernel map is normal, even
+      if it's only a page
+    <braunr> the allocated area usually gets merged with an existing
+      vm_map_entry
+    <braunr> youpi: also, i'm not sure about what you're trying to do here, so
+      my answers may be out of scope :p
+    <youpi> saving addressing space
+    <youpi> with that scheme we're using twice as much addressing space for
+      kernel buffers
+    <braunr> kernel or user task ?
+    <youpi> kernl
+    <braunr> hm are there so many wired areas ?
+    <youpi> several MiBs, yes
+    <youpi> there are also the zalloc areas
+    <braunr> that's pretty normal
+    <youpi> which I've recently incrased
+    <braunr> hm forget what i've just said about vm_page_grab()
+    <braunr> youpi: is there a particular problem caused by kernel memory
+      exhaustion ?
+    <youpi> I currently can't pass the dh_strip stage of iceweasel due to this
+    <youpi> it can not allocate a stack 
+    <braunr> a kernel thread stack ?
+    <youpi> yes
+    <braunr> that's surprising
+    <youpi> it'd be good to have a kernel memory profile
+    <braunr> vminfo is able to return the kernel map
+    <youpi> well, it's not suprising if the kernel map is full
+    <youpi> but it doesn't tell what allocates which p ieces
+    <braunr> that's what i mean, it's surprising to have a full kernel map
+    <youpi> (that's what profiling is about)
+    <braunr> right
+    <youpi> well, it's not really surprising, considering that the krenel map
+      size is arbitrarily chosen
+    <braunr> youpi: 2 GiB is really high enough
+    <youpi> it's not 2GiB, precisely
+    <youpi> there is much of the 2GiB addr space which is spent on physical
+      memory mapping
+    <youpi> then there is the virtual mapping
+    <braunr> are you sure we're talking about the kernel map, or e.g. the kmem
+      map
+    <youpi> which is currently only 192MiB
+    <youpi> the kmem_map part of kernel_map
+    <braunr> ok, the kmem_map submap then
+    <braunr> netbsd has used 128 MiB for yeas with almost no issue
+    <braunr> mach uses more kernel objects so it's reasonable to have a bigger
+      map
+    <braunr> but that big ..
+    <youpi> I've made the zalloc areas quite big
+    <youpi> err, not only zalloc area
+    <braunr> kernel stacks are allocated directly from the kernel map
+    <youpi> kalloc to 64MiB, zalloc to 64MiB
+    <youpi> ipc map size to 8MiB
+    <braunr> youpi: it could be the lack of kernel map entries
+    <youpi> and the device io map to 16MiB
+    <braunr> do you have the exact error message ?
+    <youpi> no more room for vm_map_find_entry in 71403294
+    <youpi> no more rooom for kmem_alloc_aligned in 71403294
+    <braunr> ah, aligned
+    <youpi> for a stack
+    <youpi> which is 4 pages only
+    <braunr> memory returned by kmem functions always return pages
+    <braunr> hum
+    <braunr> kmem functions always return memory in page units
+    <youpi> and my xen driver is allocating 1MiB memory for the network buffer
+    <braunr> 4 pages for kernel stacks ?
+    <youpi> through kmem_alloc_wire
+    <braunr> that seems a lot
+    <youpi> that's needed for xen page updates
+    <youpi> without having to split the update in several parts
+    <braunr> ok
+    <braunr> but are there any alignment requirements ?
+    <youpi> I guess mach  uses the alignment trick to find "self"
+    <youpi> anyway, an alignment on 4pages shouldn't be a problem
+    <braunr> i think kmem_alloc_aligned() is the generic function used both for
+      requests with and without alignment constraints
+    <youpi> so I was thinking about at least moving my xen net driver to
+      vm_grab_page instead of kmem_alloc
+    <youpi> and along this, maybe others
+    <braunr> but you only get a vm_page, you can't access the memory it
+      describes
+    <youpi> non, a lloc_aligned always aligns
+    <youpi> why?
+    <braunr> because it's not mapped
+    <youpi> there's even vm_grab_page_physical_addr
+    <youpi> it is, in the physical memory map
+    <braunr> ah, you mean using the direct mapped area
+    <youpi> yes
+    <braunr> then yes
+    <braunr> i don't know that part much
+    <youpi> what I'm afraid of is the wiring
+    <braunr> why ?
+    <youpi> because I don't want to see my page swapped out :)
+    <youpi> or whatever might happen if I don't wire it
+    <braunr> oh i'm almost sure you won't
+    <youpi> why?
+    <youpi> why some people need to wire it, and I won't?
+    <braunr> because in most mach vm derived code i've seen, you have to
+      explicitely tell the vm your area is pageable
+    <youpi> ah,  mach does such thing indeed
+    <braunr> wiring can be annoying when you're passing kernel data to external
+      tasks
+    <braunr> you have to make sure the memory isn't wired once passed
+    <braunr> but that's rather a security/resource management problem
+    <youpi> in the net driver case, it's not passed to anything else
+    <youpi> I'm seeing 19MiB kmem_alloc_wired atm
+    <braunr> looks ok to me
+    <braunr> be aware that the vm_resident code was meant for single page
+      allocations
+    <youpi> what does this mean?
+    <braunr> there is no buddy algorithm or anything else decent enough wrt
+      performance
+    <braunr> vm_page_grab_contiguous_pages() can be quite slow
+    <youpi> err, ok, but what is the relation with the question at stake ?
+    <braunr> you need 4 pages of direct mapped memory for stacks
+    <braunr> those pages need to be physically contiguous if you want to avoid
+      the mapping
+    <braunr> allocating physically contiguous pages in mach is slow
+    <braunr> :)
+    <youpi> I didn't mean I wanted to avoid the mapping for stacks
+    <youpi> for anything more than a page, kmem mapping should be fine
+    <youpi> I'm concerned with code which allocates only page per page
+    <youpi> which thus really doesn't need any mapping
+    <braunr> i don't know the mach details but in derived implementations,
+      there is almost no overhead when allocating single pages
+    <braunr> except for the tlb programming
+    <youpi> well, there is: twice as much addressing space
+    <braunr> well
+    <braunr> netbsd doesn't directly map physical memory
+    <braunr> and for others, like freebsd
+    <braunr> the area is just one vm_map_entry
+    <braunr> and on modern mmus, 4 MiBs physical mappings are used in pmap
+    <youpi> again, I don't care about tlb & performance
+    <youpi> just about the addressing space
+    <braunr> hm
+    <braunr> you say "twice"
+    <youpi> which is short when you're trying to link crazy stuff like
+      iceweasel & co
+    <youpi> yes
+    <braunr> ok, the virtual space is doubled
+    <youpi> yes
+    <braunr> but the resources consume to describe them aren't
+    <braunr> even on mach
+    <youpi> since you have both the physical mapping and the kmem mapping
+    <youpi> I don't care much about the resources
+    <youpi> but about addressing space
+    <braunr> well there are a limited numbers of solutions
+    <youpi> the space it takes  and has to be taken from something else, that
+      is,  here physical memory available to Mach
+    <braunr> reduce the physical mapping
+    <braunr> increase the kmem mapping
+    <braunr> or reduce kernel memory consumption
+    <youpi> and instead of taking the space from physical  mapping, we can as
+      well avoid doubling the space consumption when it's trivial lto
+    <youpi> yes, the hird
+    <youpi> +t
+    <youpi> that's what I'm asking from the beginning :)
+    <braunr> 18:21 < youpi> I don't care much about the resources
+    <braunr> actually, you care :)
+    <youpi> yes and no
+    <braunr> i understand what you mean
+    <youpi> not in the sense "it takes a page_t to allocate a page"
+    <braunr> you want more virtual space, and aren't that much concerned about
+      the number of objects used
+    <youpi> yes
+    <braunr> then it makes sense
+    <braunr> but in this case, it could be a good idea to generalize it
+    <braunr> have our own kmalloc/vmalloc interfaces
+    <braunr> maybe a gsoc project :)
+    <youpi> err, don't we have them already?
+    <youpi> I mean, what exactly do you want to generalize?
+    <braunr> mach only ever had vmalloc
+    <youpi> we already have a hell lot of allocators :)
+    <youpi> and it's a pain to distribute the available space to them
+    <braunr> yes
+    <braunr> but what you basically want is to introduce something similar to
+      kmalloc for single pages
+    <youpi> or just patch the few cases that need it into just grabbing a page
+    <youpi> there are probably not so many
+    <braunr> ok
+    <braunr> i've just read vm_page_grab()
+    <braunr> it only removes a page from the free list
+    <braunr> other functions such as vm_page_alloc insert them afterwards
+    <braunr> if a page is in no list, it can't be paged out
+    <braunr> so i think it's probably safe to assume it's naturally wired
+    <braunr> you don't even need a call to vm_page_wire or a flag of some sort
+    <youpi> ok
+    <braunr> although considering the low amount of work done by
+      vm_page_wire(), you could, for clarity
+    <youpi> braunr: I was also wondering about the VM_PAGE_FREE_RESERVED & such
+      constants
+    <youpi> they're like 50 pages
+    <youpi> is this still reasonable  nowadays?
+    <braunr> that's a question i'm still asking myself quite often :)
+    <youpi> also, the BURST_{MAX,MIN} & such in vm_pageout.c are probably out
+      of date?
+    <braunr> i didn't study the pageout code much
+    <youpi> k
+    <braunr> but correct handling of low memory thresholds is a good point to
+      keep in mind
+    <braunr> youpi: i often wonder how linux can sometimes have so few free
+      pages left and still be able to work without any visible failure
+    <youpi> well, as long as you have enough pages to be able to make progress,
+      you're fine
+    <youpi> that' the point of the RESERVED pages in mach I guess
+    <braunr> youpi: yes but, obviously, hard values are *bad*
+    <braunr> linux must adjust it, depending on the number of processors, the
+      number of pdflush threads, probably other things i don't have in mind
+    <braunr> i don't know what should make us adjust that value in mach
+    <youpi> which value?
+    <braunr> the size of the reserved pool
+    <youpi> I don't think it's adjusted
+    <braunr> that's what i'm saying
+    <braunr> i guess there is an #ifndef line for arch specific definitions
+    <youpi> err, you just said linux must adjust it :
+    <youpi> ))
+    <youpi> there is none
+    <braunr> linux adjusts it dynamically
+    <braunr> well ok
+    <braunr> that's another way to say it
+    <braunr> we don't have code to get rid of this macro
+    <braunr> but i don't even know how we, as maintainers, are supposed to
+      guess it
diff --git a/open_issues/gnumach_memory_management_physical_memory.mdwn b/open_issues/gnumach_memory_management_physical_memory.mdwn
new file mode 100644
index 00000000..58fefe1f
--- /dev/null
+++ b/open_issues/gnumach_memory_management_physical_memory.mdwn
@@ -0,0 +1,46 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_gnumach]]
+
+IRC, freenode, #hurd, 2011-10:
+
+    <braunr> antrik: about our physical memory limitations, i told you some
+      time ago that part of it was due to the linux drivers
+    <braunr> and i mentioned the paper concerning the integration of the linux
+      drivers written at the time
+    <braunr> it does indeed tell that mach, which used the common 3G->4G area
+      for the kernel space had to be adapted
+    <braunr> because linux used segmentation so that kernel addresses matched
+      physical addresses
+    <braunr> and it looks like some (many) drivers require that
+    <braunr> our current gnumach actually does this (which i found surprising
+      when i first found it)
+    <braunr> and i believe the easy solution to exceed this limitation is to
+      use a strategy similar to what linux still does on i386
+    <braunr> some highmem support
+    <braunr> we could alter the vm_resident module so that, by default, it
+      still looks for pages in the low 0-800 (or 0-1800 on debian patched
+      kernels) area
+    <braunr> but for everything else than the kernel, e.g. all user processes
+    <braunr> we could use a flag or a specialized function that would first
+      look in the highmem pool for available physical pages to map
+    <braunr> the only thing i'm not yet sure of is about user/kernel transfers
+    <braunr> if virtual addresses and copies are always cleanly done, then it's
+      ok
+    <braunr> and i really hope our linux drivers do so :)
+    <braunr> (i mean ,the glue code ofc)
+
+2011-10-23:
+
+    <youpi> braunr: I believe, like Linus, that highmem support is a nightmare
+    <antrik> braunr: uhm... the drivers want virtual addressses to match
+      physical ones? I guess that means switching address spaces before any
+      driver code is executed?...
diff --git a/open_issues/issue_tracking.mdwn b/open_issues/issue_tracking.mdwn
index 55c7b87b..72bb3b77 100644
--- a/open_issues/issue_tracking.mdwn
+++ b/open_issues/issue_tracking.mdwn
@@ -102,6 +102,84 @@ IRC, freenode, #hurd, 2011-08-31:
     <mattl> RT is not the easiest thing to set up, but works pretty well once
       it's running.
 
+IRC, freenode, #hurd, 2011-10-19:
+
+    <antrik> tschwinge: BTW, what happened to the plan of killing help-hurd?
+    <antrik> (and possibly some other lists)
+    <tschwinge> antrik: That plan got stalled, obviously.  ;-)
+    <tschwinge> antrik: Now, I had proposed to use hurd-dev for development,
+      and turn bug-hurd into a debbugs bug reportling list.  That proposal has
+      not heard any supportive/unsupportive votes yet.
+    <tschwinge> hurd-devel.  That's the name.
+    <tschwinge> And turn off hurd-devel-readers.  And turn off help-hurd.
+    <tschwinge> And web-hurd.
+    <tschwinge> Keep l4-hurd.
+    <antrik> yeah, I haven't replied regarding bug-hurd vs. hurd-devel, as I'm
+      not quite sure myself
+    <antrik> on one hand, a dedicated bug list can be convenient; on the other
+      hand, this kind of splits always causes unnecessary overhead IMHO
+    <antrik> also, hurd-devel would obviously be *only* for development, so in
+      this scenario we actually would *need* to keep something like help-hurd
+      as well...
+    <antrik> I think I'd prefer the non-exclusive mode for debbugs... would
+      have to check again how it works exactly though :-)
+    <tschwinge> antrik: I quite liked that exclusive mode for it automatically
+      archives discussions grouped by threads for easy reference.
+    <tschwinge> antrik: And, the very most of bug-hurd emails are ``issues'' of
+      some sort: bug report, patch (that needs to be tracked until it is
+      applied, etc.
+    <antrik> tschwinge: exclusive mode would just mean that people would take
+      most of these discussion elsewhere, and the bug list would only be used
+      when someone explicitly wants something tracked as a bug...
+    <antrik> ideally, the bug tracker should only track things if explicitly
+      CCed. ideally, it should be possible to forward mails that have been
+      posted without CC, so they can be tracked retroactively...
+    <tschwinge> antrik: Why do you think that people would take discussions
+      elsewhere?
+    <antrik> because most people don't consider it useful to put every random
+      question or remark in an issue tracker
+    <antrik> IMHO it should be easy to turn messages into tickets/followups;
+      but it should not happen automatically
+    <tschwinge> What if people wouldn't even notice that their issues is kept
+      in a tracker, too?
+    <draculus> It might send a notification of some sort?
+    <antrik> I once posted to a list with RT in exclusive mode, and quite
+      frankly, I considered it rather strange to get a ticket created for my
+      message :-)
+    <antrik> tschwinge: that would only be useful if you always close tickets
+      for irrelevant or finished discussions, mark duplicates etc. -- and this
+      would have to happen silently, without noise for most other people
+      following the list...
+    <antrik> tschwinge: are you sure you want to do that?... :-)
+    <tschwinge> Yes.
+    <tschwinge> Because that way we don't lose so much stuff as we currently
+      do.
+    <antrik> well, the decision is up to you in that case...
+    <tschwinge> In fact, probably less than manually archiving the content, as
+      I'm doing now, partially.
+    <tschwinge> antrik: Well, I'm just out for getting some comments.
+    <antrik> it would further reduce our bus factor though :-(
+    <tschwinge> That already is low enough that it doesn't matter anymore...
+    <tschwinge> antrik: So, to sum up, you'd use non-exclusive mode, but are
+      not actively opposed to exclusive mode as long as it doesn't too much
+      disturbe any procedures you're currently using?
+    <antrik> well, if it happens mostly in the background, I don't see why
+      anyone should be opposed...
+    <antrik> just make sure people posting to the list don't get a "ticket
+      created" message in response :-)
+    <antrik> it would make it harder though for people to explicitly track
+      issue they are interested in I fear
+    <antrik> when using non-exclusive mode, and people explicitly CC things to
+      the tracker, which sends a notice about a ticket being created, everyone
+      sees that and can act accordingly. if everything happens in the
+      background, few people would even think about it...
+    <antrik> so non-exclusive mode probably needs more effort to keep in order;
+      but it would be more useful too...
+    <tschwinge> Well, but with exclusive mode, people don't lose anything
+      compared to the current state, do they?
+    <antrik> tschwinge: probably not compared to the current state... but
+      possibly compared to a well-used non-exclusive mode :-)
+
 
 # Further Systems
 
diff --git a/open_issues/libpthread_assertion_thread_prevp.mdwn b/open_issues/libpthread_assertion_thread_prevp.mdwn
new file mode 100644
index 00000000..1418bea1
--- /dev/null
+++ b/open_issues/libpthread_assertion_thread_prevp.mdwn
@@ -0,0 +1,52 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!meta title="libpthread: __pthread_enqueue: Assertion `thread->prevp == 0'
+failed"]]
+
+[[!tag open_issue_libpthread]]
+
+IRC, OFTC, #debian-hurd, 2011-10-21:
+
+    [Python testsuite]
+    <pinotree> [169/340/1] test_logging
+    <pinotree> python:
+      /home/pino/sources/hurd/hurd-20110519/./libpthread/pthread/pt-internal.h:109:
+      __pthread_enqueue: Assertion `thread->prevp == 0' failed.
+    <pinotree> sigh
+
+IRC, freenode, #hurd, 2011-10-21:
+
+    <pinotree> am i missing anything, or in libpthread the __pthread_threads
+      list does not ever has elements removed from it?
+    <pinotree> ... thus potentially causing
+      "./libpthread/pthread/pt-internal.h:109: __pthread_enqueue: Assertion
+      `thread->prevp == 0' failed." because threads can be appended on
+      __pthread_dealloc() to the __pthread_free_threads list as well?
+    <pinotree> maybe reusing the same next+prevp pointers in the __pthread
+      struct for more than one list at the same time isn't a good idea...
+
+2011-10-23:
+
+    <youpi> pinotree: I don't understand the relation between thread->prevp !=
+      0 and the __pthread_threads list
+    <youpi> the list never has elements removed indeed, since libpthread never
+      frees __pthread structures apparently
+    <pinotree> youpi: ye sorry, that relation is indeed nonsense
+    <youpi> in which condition did you get prevp != 0
+    <pinotree> i wa trying to find some explaination for the "thread->prevp ==
+      0" assertion in the _queue function
+    <youpi> ?
+    <pinotree> *was
+    <youpi> it's not obvious to me how libpthread makes sure the various
+      cond/mutex/rwlock make sure that it's not queued several times
+    <pinotree> yeah
+    <pinotree> apparently prevp/next are used for lists of held
+      waitcond/mutex/rwlock and free threads
diff --git a/open_issues/libpthread_pthread_key_create_reuse.mdwn b/open_issues/libpthread_pthread_key_create_reuse.mdwn
index a5704d0f..ca2da2f5 100644
--- a/open_issues/libpthread_pthread_key_create_reuse.mdwn
+++ b/open_issues/libpthread_pthread_key_create_reuse.mdwn
@@ -10,10 +10,10 @@ License|/fdl]]."]]"""]]
 
 [[!meta title="libpthread: pthread_key_create, reuse"]]
 
-IRC, FreeNode, #hurd, 2011-07-02
-
 [[!tag open_issue_libpthread]]
 
+IRC, FreeNode, #hurd, 2011-07-02:
+
     < pinotree> hm, maybe i found a libpthread bug
     * pinotree tries a testcase
     < pinotree> yesssss, found the bug :)
@@ -47,3 +47,36 @@ IRC, FreeNode, #hurd, 2011-07-02
       veeery quick glance
 
 Test program: [[pthread_key_create_reuse.c]]
+
+
+2011-11-01:
+
+    <pinotree> youpi: about the bug with pthread keys (reuse): would be an
+      acceptable solution having a mutex for the thread_specifics of each
+      thread?
+    <youpi> you mean one per thread, one global, or one per key, or ?
+    <youpi> what is it supposed to protect?
+    <pinotree> the thread_specifics of each thread
+    <youpi> pinotree: but against what?
+    <pinotree> the idea would be: when destroying a key, iterate over all the
+      exiting threads and remove the key data from the thread_specifics of each
+      thread
+    <youpi> one of the issue is getting to browse through the whole list of
+      threads
+    <youpi> the other is concurrency between that, and a thread dying
+    <pinotree> there's the __pthread_threads_lock rwlock
+    <youpi> it should be enough to keep it locked during the iteration
+    <pinotree> but that wouldn't be enough when one thread is destroying a key,
+      and another one is doing {get,set}specific() on that key
+    <youpi> that's not supposed to happen
+    <pinotree> mmm
+    <youpi> “The effect of calling pthread_getspecific() or
+      pthread_setspecific() with a     key value not obtained from
+      pthread_key_create() or after key has been     deleted with
+      pthread_key_delete() is undefined.”
+    <youpi> undefined -> you are allowed to just blow up
+    <pinotree> but it's not been deleted yet... :)
+    <youpi> it could be, just a matter of time
+    <youpi> you're not supposed to rely on time-luckyness :)
+    <pinotree> mmm
+    <pinotree> bah, you've convinced me ( :) )
diff --git a/open_issues/libpthread_set_stack_size.mdwn b/open_issues/libpthread_set_stack_size.mdwn
new file mode 100644
index 00000000..68f81752
--- /dev/null
+++ b/open_issues/libpthread_set_stack_size.mdwn
@@ -0,0 +1,25 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_glibc open_issue_libpthread]]
+
+IRC, freenode, #hurd, 2011-10-21:
+
+    <pinotree> maybe i'm missing something... what's the reason for not
+      allowing setting a different stack size in libpthread?
+
+2011-10-23:
+
+    <youpi> pinotree: the threadvars implementations
+    <youpi> which needs to find the variables according to sp value
+    <youpi> of course, since we now have TLS, threadvards can go away
+    <youpi> it's simply on the so-long TODO list
+
+[[glibc/t/tls-threadvar]].
diff --git a/open_issues/mission_statement.mdwn b/open_issues/mission_statement.mdwn
new file mode 100644
index 00000000..212d65e7
--- /dev/null
+++ b/open_issues/mission_statement.mdwn
@@ -0,0 +1,39 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_documentation]]
+
+IRC, freenode, #hurd, 2011-10-12:
+
+    <ArneBab> we have a mission statement: http://hurd.gnu.org
+    <Gorodish> yes
+    <Gorodish> but it's quite wishy washy
+    <Gorodish> considering all the elegant capability Hurd potentially has to
+      offer
+    <antrik> Gorodish: it's true that the mission statement is very
+      abstract... but then, it's hard to put anything more specific into 35
+      words
+    <Gorodish> not with some practice
+    <Gorodish> I notice programers tend to speak and write in terms of what
+      something does
+    <Gorodish> not what it is
+    <Gorodish> the "What is Hurd" is a good example
+    <Gorodish> there's a lot of interesting information there
+    <Gorodish> but the way it's ordered is odd
+    <antrik> a mission statement is not primarily a PR instrument; but rather a
+      guide that allows separating things that benefit the common goal from
+      things that don't...
+    <antrik> I agree that some actual marketing material in addition would be
+      nice :-)
+    <Gorodish> yes
+    <Gorodish> the modesty of Developers that work on FOSS projects never
+      ceases to amaze me
+    <Gorodish> I agree that the informational, factual, results oriented
+      documentation is the primary objective of documenting
diff --git a/open_issues/performance/io_system/binutils_ld_64ksec.mdwn b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
index 359d5fee..37fe9c53 100644
--- a/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
+++ b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
@@ -27,6 +27,10 @@ extracted from cdf7c161ebd4a934c9e705d33f5247fd52975612 sources, 2010-10-24.
 On the idle grubber, this one repeatedly takes a few minutes wall time to
 complete successfully, contrary to a few seconds on a GNU/Linux system.
 
+> On order of slowness may in fact be due to a Xen-specific issue, see
+> [[xen_lseek]].  (But there are probably still one or two orders left, even
+> without Xen.)
+
 While processing the object files, there is heavy interaction with the relevant
 [[hurd/translator/ext2fs]] process.  Running [[hurd/debugging/rpctrace]] on
 the testee shows that (primarily) an ever-repeating series of `io_seek` and
diff --git a/open_issues/pfinet_vs_system_time_changes.mdwn b/open_issues/pfinet_vs_system_time_changes.mdwn
index 714c8784..513cbc73 100644
--- a/open_issues/pfinet_vs_system_time_changes.mdwn
+++ b/open_issues/pfinet_vs_system_time_changes.mdwn
@@ -17,7 +17,7 @@ IRC, unknown channel, unknown date.
 
 This was very likely a misdiagnosis:
 
-IRC, freenode, #hurd, 2011-03-25
+IRC, freenode, #hurd, 2011-03-25:
 
     <tschwinge> antrik: I suspect it'S some timing stuff in pfinet that perhaps
       uses absolute time, and somehow wildely gets confused?
@@ -40,3 +40,21 @@ IRC, freenode, #hurd, 2011-03-25
     <tschwinge> (The other way round, you might likely get some integer
       wrap-around, and thus the same result.)
     <tschwinge> Yes.
+
+IRC, freenode, #hurd, 2011-10-26:
+
+    <antrik> anyways, when ntpdate adjusts to the past, the connections hang,
+      roughly for the amount of time being adjusted
+    <antrik> they do not die though
+    <antrik> (well, if it's long enough, they probably timeout on the other
+      side...)
+
+IRC, freenode, #hurd, 2011-10-27:
+
+    <antrik> oh, another interesting thing I observed is that the the subhurd
+      pfinet did *not* drop the connection... only the main Hurd one. I thought
+      the clock is system-wide?...
+    <tschwinge> It is.
+    <antrik> it's really fascinating that only the pfinet on the Hurd instance
+      where I set the date is affected, and not the pfinet in the other
+      instance
diff --git a/open_issues/screen_dead_session.mdwn b/open_issues/screen_dead_session.mdwn
index cdd3f322..fe51523b 100644
--- a/open_issues/screen_dead_session.mdwn
+++ b/open_issues/screen_dead_session.mdwn
@@ -1,4 +1,4 @@
-[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
+[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]]
 
 [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
 id="license" text="Permission is granted to copy, distribute and/or modify this
@@ -14,7 +14,10 @@ Comparing to GNU/Linux, on GNU/Hurd it happens much more often and easily for
 *screen* sessions to become *dead*.  This is annoying, as it defeats one of
 *screen*'s main purposes.
 
-One reproducible scenario goes like this:
+[[!toc]]
+
+
+# One reproducible scenario goes like this
 
   * `ssh [somewhere]`,
 
@@ -28,7 +31,8 @@ One reproducible scenario goes like this:
   * at some point, *P* will terminate / hang (after having received some kind
     of signal?), and the *screen* session will be reported as *dead*.
 
-Another one, not as often reproduced:
+
+# Another one, not as often reproduced
 
   * `ssh [somewhere]`,
 
@@ -43,3 +47,23 @@ Another one, not as often reproduced:
     (after having received some kind of signal?), and the *screen* session will
     *immediatelly* be reported as *dead*.  (Perhaps the other way round: upon
     re-attaching, the *screen* session goes bonkers and takes *P* with it?)
+
+
+# IRC, freenode, #hurd, 2011-10-19
+
+    <antrik> tschwinge: hm... haven't seen screen dying in a long time
+    <tschwinge> antrik: It's easy, and goes like this: have a session on one
+      system, log in from another, do screen -x and wait some time.
+    <antrik> I do this regularily. haven't had a crash in ages.
+    <antrik> (BTW, I'm not sure I ever had a crash on srceen -x... at that
+      time, I wasn't using -x. I often had crashes with screen -r. my
+      impression back then was that it works better when doing -rd -- in fact,
+      I always do that now, so I can't say whether crashes still happen with
+      only -r...)
+
+2011-10-26:
+
+    <antrik> so I was saying the other day that I haven't had a screen crash in
+      a long time... well, here it was :-(
+    <antrik> this time it didn't crash on reconnect though, but already
+      before. probably when I killed the hanging ssh connection
diff --git a/open_issues/user-space_device_drivers.mdwn b/open_issues/user-space_device_drivers.mdwn
index e929f2bf..70c3c6dc 100644
--- a/open_issues/user-space_device_drivers.mdwn
+++ b/open_issues/user-space_device_drivers.mdwn
@@ -97,7 +97,7 @@ IRC, freenode, #hurd, 2011-07-27
 
           * Hurd on L4: deva, fabrica
 
-          * [[DDE]]
+          * [[/DDE]]
 
       * Minix 3
 
@@ -195,7 +195,7 @@ IRC, freenode, #hurd, 2011-07-27
 
 # External Projects
 
-  * [[DDE]]
+  * [[/DDE]]
 
   * <http://ertos.nicta.com.au/research/drivers/uldd/>
 
diff --git a/open_issues/xen_lseek.mdwn b/open_issues/xen_lseek.mdwn
new file mode 100644
index 00000000..accc7c8f
--- /dev/null
+++ b/open_issues/xen_lseek.mdwn
@@ -0,0 +1,35 @@
+[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_xen]]
+
+IRC, freenode, #hurd, 2011-11-02:
+
+    <youpi> btw, we have a performance issue with xen
+    <youpi> an lseek() call costs a huge lot
+    <youpi> like 1ms
+    <youpi> while the same costs just a few dozens µs with kvm
+    <youpi> there's of course the cost of switching between ring3, ring0,
+      ring1, ring0, ring3, but still
+    <gianluca> oh, nice.
+    <youpi> lseek is supposed to perform only a back&forth
+    <youpi> and I don't observe disk activity, so it's not waiting for the disk
+      to complete whatever atime change & such :)
+    <youpi> it was mentioned that perhaps xen in hvm mode with pv drivers would
+      be faster
+    <youpi> thanks to the ring3/"1" switching  being done by the processor
+    <youpi> (and assuming npt)
+    <gianluca> hm
+    <gianluca> i'll look into that, sounds fun.
+    <gianluca> :)
+    <tschwinge> Here is a testcase:
+      http://www.gnu.org/software/hurd/open_issues/performance/io_system/binutils_ld_64ksec.html
+
+[[performance/io_system/binutils_ld_64ksec]].