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diff --git a/open_issues/performance/io_system/binutils_ld_64ksec.mdwn b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
deleted file mode 100644
index 931fd0ee..00000000
--- a/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
+++ /dev/null
@@ -1,39 +0,0 @@
-[[!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
-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]]
-
-This one may be considered as a testcase for [[I/O system
-optimization|community/gsoc/project_ideas/disk_io_performance]].
-
-It is taken from the [[binutils testsuite|binutils]],
-`ld/ld-elf/sec64k.exp`, where this
-test may occasionally [[trigger a timeout|binutils#64ksec]].  It is
-extracted from cdf7c161ebd4a934c9e705d33f5247fd52975612 sources, 2010-10-24.
-
-    $ wget -O - http://www.gnu.org/software/hurd/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz | xz -d | tar -x
-    $ cd test/
-    $ \time ./ld-new.stripped -o dump dump?.o dump??.o
-    0.00user 0.00system 2:46.11elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k
-    0inputs+0outputs (0major+0minor)pagefaults 0swaps
-
-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.
-
-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
-`io_read` is being processed.  Running the testee on GNU/Linux with strace
-shows the equivalent thing (`_llseek`, `read`) -- but Linux' I/O system isn't
-as slow as the Hurd's.
-
-As Samuel figured out later, this slowness may in fact be due to a Xen-specific
-issue, see [[Xen_lseek]].  After the latter has been addressed, we can
-re-evaluate this issue here.
diff --git a/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz b/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz
deleted file mode 100644
index 6d7c606c..00000000
--- a/open_issues/performance/io_system/binutils_ld_64ksec/test.tar.xz
+++ /dev/null
diff --git a/open_issues/performance/io_system/clustered_page_faults.mdwn b/open_issues/performance/io_system/clustered_page_faults.mdwn
deleted file mode 100644
index a3baf30d..00000000
--- a/open_issues/performance/io_system/clustered_page_faults.mdwn
+++ /dev/null
@@ -1,162 +0,0 @@
-[[!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_hurd]]
-
-[[community/gsoc/project_ideas/disk_io_performance]].
-
-[[!toc]]
-
-
-# IRC, freenode, #hurd, 2011-02-16
-
-    <braunr> exceptfor the kernel, everything in an address space is
-      represented with a VM object
-    <braunr> those objects can represent anonymous memory (from malloc() or
-      because of a copy-on-write)
-    <braunr> or files
-    <braunr> on classic Unix systems, these are files
-    <braunr> on the Hurd, these are memory objects, backed by external pagers
-      (like ext2fs)
-    <braunr> so when you read a file
-    <braunr> the kernel maps it from ext2fs in your address space
-    <braunr> and when you access the memory, a fault occurs
-    <braunr> the kernel determines it's a region backed by ext2fs
-    <braunr> so it asks ext2fs to provide the data
-    <braunr> when the fault is resolved, your process goes on
-    <etenil> does the faul occur because Mach doesn't know how to access the
-      memory?
-    <braunr> it occurs because Mach intentionnaly didn't back the region with
-      physical memory
-    <braunr> the MMU is programmed not to know what is present in the memory
-      region
-    <braunr> or because it's read only
-    <braunr> (which is the case for COW faults)
-    <etenil> so that means this bit of memory is a buffer that ext2fs loads the
-      file into and then it is remapped to the application that asked for it
-    <braunr> more or less, yes
-    <braunr> ideally, it's directly written into the right pages
-    <braunr> there is no intermediate buffer
-    <etenil> I see
-    <etenil> and as you told me before, currently the page faults are handled
-      one at a time
-    <etenil> which wastes a lot of time
-    <braunr> a certain amount of time
-    <etenil> enough to bother the user :)
-    <etenil> I've seen pages have a fixed size
-    <braunr> yes
-    <braunr> use the PAGE_SIZE macro
-    <etenil> and when allocating memory, the size that's asked for is rounded
-      up to the page size
-    <etenil> so if I have this correctly, it means that a file ext2fs provides
-      could be split into a lot of pages
-    <braunr> yes
-    <braunr> once in memory, it is managed by the page cache
-    <braunr> so that pages more actively used are kept longer than others
-    <braunr> in order to minimize I/O
-    <etenil> ok
-    <braunr> so a better page cache code would also improve overall performance
-    <braunr> and more RAM would help a lot, since we are strongly limited by
-      the 768 MiB limit
-    <braunr> which reduces the page cache size a lot
-    <etenil> but the problem is that reading a whole file in means trigerring
-      many page faults just for one file
-    <braunr> if you want to stick to the page clustering thing, yes
-    <braunr> you want less page faults, so that there are less IPC between the
-      kernel and the pager
-    <etenil> so either I make pages bigger
-    <etenil> or I modify Mach so it can check up on a range of pages for faults
-      before actually processing
-    <braunr> you *don't* change the page size
-    <etenil> ah
-    <etenil> that's hardware isn't it?
-    <braunr> in Mach, yes
-    <etenil> ok
-    <braunr> and usually, you want the page size to be the CPU page size
-    <etenil> I see
-    <braunr> current CPU can support multiple page sizes, but it becomes quite
-      hard to correctly handle
-    <braunr> and bigger page sizes mean more fragmentation, so it only suits
-      machines with large amounts of RAM, which isn't the case for us
-    <etenil> ok
-    <etenil> so I'll try the second approach then
-    <braunr> that's what i'd recommand
-    <braunr> recommend*
-    <etenil> ok
-
-
-# IRC, freenode, #hurd, 2011-02-16
-
-    <antrik> etenil: OSF Mach does have clustered paging BTW; so that's one
-      place to start looking...
-    <antrik> (KAM ported the OSF code to gnumach IIRC)
-    <antrik> there is also an existing patch for clustered paging in libpager,
-      which needs some adaptation
-    <antrik> the biggest part of the task is probably modifying the Hurd
-      servers to use the new interface
-    <antrik> but as I said, KAM's code should be available through google, and
-      can serve as a starting point
-
-<http://lists.gnu.org/archive/html/bug-hurd/2010-06/msg00023.html>
-
-
-# IRC, freenode, #hurd, 2011-07-22
-
-    <braunr> but concerning clustered pagins/outs, i'm not sure it's a mach
-      interface limitation
-    <braunr> the external memory pager interface does allow multiple pages to
-      be transfered
-    <braunr> isn't it an internal Mach VM problem ?
-    <braunr> isn't it simply the page fault handler ?
-    <antrik> braunr: are you sure? I was under the impression that changing the
-      pager interface was among the requirements...
-    <antrik> hm... I wonder whether for pageins, it could actually be handled
-      in the pages instead of Mach... though this wouldn't work for pageouts,
-      so probably not very helpful
-    <antrik> err... in the pagers
-    <braunr> antrik: i'm almost sure
-    <braunr> but i've be proven wrong many times, so ..
-    <braunr> there are two main facts that lead me to think this
-    <braunr> 1/
-      http://www.gnu.org/software/hurd/gnumach-doc/Memory-Objects-and-Data.html#Memory-Objects-and-Data
-      says lengths are provided and doesn't mention the limitation
-    <braunr> 2/ when reading about UVM, one of the major improvements (between
-      10 and 30% of global performance depending on the benchmarks) was
-      implementing the madvise semantics
-    <braunr> and this didn't involve a new pager interface, but rather a new
-      page fault handler
-    <antrik> braunr: hm... the interface indeed looks like it can handle
-      multiple pages in both directions... perhaps it was at the Hurd level
-      where the pager interface needs to be modified, not the Mach one?...
-    <braunr> antrik: would be nice wouldn't it ? :)
-    <braunr> antrik: more probably the page fault handler
-
-
-# IRC, freenode, #hurd, 2011-09-28
-
-    <slpz> antrik: I've just recovered part of my old multipage I/O work
-    <slpz> antrik: I intend to clean and submit it after finishing the changes
-      to the pageout system.
-    <antrik> slpz: oh, great!
-    <antrik> didn't know you worked on multipage I/O
-    <antrik> slpz: BTW, have you checked whether any of the work done for GSoC
-      last year is any good?...
-    <antrik> (apart from missing copyright assignments, which would be a
-      serious problem for the Hurd parts...)
-    <slpz> antrik: It was seven years ago, but I did:
-      http://www.mail-archive.com/bug-hurd@gnu.org/msg10285.html :-)
-    <slpz> antrik: Sincerely, I don't think the quality of that code is good
-      enough to be considered... but I think it was my fault as his mentor for
-      not correcting him soon enough...
-    <antrik> slpz: I see
-    <antrik> TBH, I feel guilty myself, for not asking about the situation
-      immediately when he stopped attending meetings...
-    <antrik> slpz: oh, you even already looked into vm_pageout_scan() back then
-      :-)
diff --git a/open_issues/performance/io_system/read-ahead.mdwn b/open_issues/performance/io_system/read-ahead.mdwn
deleted file mode 100644
index d6a98070..00000000
--- a/open_issues/performance/io_system/read-ahead.mdwn
+++ /dev/null
@@ -1,391 +0,0 @@
-[[!meta copyright="Copyright © 2011, 2012 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_hurd]]
-
-[[!toc]]
-
-
-# [[community/gsoc/project_ideas/disk_io_performance]]
-
-
-# 2011-02
-
-[[Etenil]] has been working in this area.
-
-
-## IRC, freenode, #hurd, 2011-02-13
-
-    <etenil> youpi: Would libdiskfs/diskfs.h be in the right place to make
-      readahead functions?
-    <youpi> etenil: no, it'd rather be at the memory management layer,
-      i.e. mach, unfortunately
-    <youpi> because that's where you see the page faults
-    <etenil> youpi: Linux also provides a readahead() function for higher level
-      applications. I'll probably have to add the same thing in a place that's
-      higher level than mach
-    <youpi> well, that should just be hooked to the same common implementation
-    <etenil> the man page for readahead() also states that portable
-      applications should avoid it, but it could be benefic to have it for
-      portability
-    <youpi> it's not in posix indeed
-
-
-## IRC, freenode, #hurd, 2011-02-14
-
-    <etenil> youpi: I've investigated prefetching (readahead) techniques. One
-      called DiskSeen seems really efficient. I can't tell yet if it's patented
-      etc. but I'll keep you informed
-    <youpi> don't bother with complicated techniques, even the most simple ones
-      will be plenty :)
-    <etenil> it's not complicated really
-    <youpi> the matter is more about how to plug it into mach
-    <etenil> ok
-    <youpi> then don't bother with potential pattents
-    <antrik> etenil: please take a look at the work KAM did for last year's
-      GSoC
-    <youpi> just use a trivial technique :)
-    <etenil> ok, i'll just go the easy way then
-
-    <braunr> antrik: what was etenil referring to when talking about
-      prefetching ?
-    <braunr> oh, madvise() stuff
-    <braunr> i could help him with that
-
-
-## IRC, freenode, #hurd, 2011-02-15
-
-    <etenil> oh, I'm looking into prefetching/readahead to improve I/O
-      performance
-    <braunr> etenil: ok
-    <braunr> etenil: that's actually a VM improvement, like samuel told you
-    <etenil> yes
-    <braunr> a true I/O improvement would be I/O scheduling
-    <braunr> and how to implement it in a hurdish way
-    <braunr> (or if it makes sense to have it in the kernel)
-    <etenil> that's what I've been wondering too lately
-    <braunr> concerning the VM, you should look at madvise()
-    <etenil> my understanding is that Mach considers devices without really
-      knowing what they are
-    <braunr> that's roughly the interface used both at the syscall() and the
-      kernel levels in BSD, which made it in many other unix systems
-    <etenil> whereas I/O optimisations are often hard disk drives specific
-    <braunr> that's true for almost any kernel
-    <braunr> the device knowledge is at the driver level
-    <etenil> yes
-    <braunr> (here, I separate kernels from their drivers ofc)
-    <etenil> but Mach also contains some drivers, so I'm going through the code
-      to find the apropriate place for these improvements
-    <braunr> you shouldn't tough the drivers at all
-    <braunr> touch
-    <etenil> true, but I need to understand how it works before fiddling around
-    <braunr> hm
-    <braunr> not at all
-    <braunr> the VM improvement is about pagein clustering
-    <braunr> you don't need to know how pages are fetched
-    <braunr> well, not at the device level
-    <braunr> you need to know about the protocol between the kernel and
-      external pagers
-    <etenil> ok
-    <braunr> you could also implement pageout clustering
-    <etenil> if I understand you well, you say that what I'd need to do is a
-      queuing system for the paging in the VM?
-    <braunr> no
-    <braunr> i'm saying that, when a page fault occurs, the kernel should
-      (depending on what was configured through madvise()) transfer pages in
-      multiple blocks rather than one at a time
-    <braunr> communication with external pagers is already async, made through
-      regular ports
-    <braunr> which already implement message queuing
-    <braunr> you would just need to make the mapped regions larger
-    <braunr> and maybe change the interface so that this size is passed
-    <etenil> mmh
-    <braunr> (also don't forget that page clustering can include pages *before*
-      the page which caused the fault, so you may have to pass the start of
-      that region too)
-    <etenil> I'm not sure I understand the page fault thing
-    <etenil> is it like a segmentation error?
-    <etenil> I can't find a clear definition in Mach's manual
-    <braunr> ah
-    <braunr> it's a fundamental operating system concept
-    <braunr> http://en.wikipedia.org/wiki/Page_fault
-    <etenil> ah ok
-    <etenil> I understand now
-    <etenil> so what's currently happening is that when a page fault occurs,
-      Mach is transfering pages one at a time and wastes time 
-    <braunr> sometimes, transferring just one page is what you want
-    <braunr> it depends on the application, which is why there is madvise()
-    <braunr> our rootfs, on the other hand, would benefit much from such an
-      improvement
-    <braunr> in UVM, this optimization is account for around 10% global
-      performance improvement
-    <braunr> accounted*
-    <etenil> not bad
-    <braunr> well, with an improved page cache, I'm sure I/O would matter less
-      on systems with more RAM
-    <braunr> (and another improvement would make mach support more RAM in the
-      first place !)
-    <braunr> an I/O scheduler outside the kernel would be a very good project
-      IMO
-    <braunr> in e.g. libstore/storeio
-    <etenil> yes
-    <braunr> but as i stated in my thesis, a resource scheduler should be as
-      close to its resource as it can
-    <braunr> and since mach can host several operating systems, I/O schedulers
-      should reside near device drivers
-    <braunr> and since current drivers are in the kernel, it makes sens to have
-      it in the kernel too
-    <braunr> so there must be some discussion about this
-    <etenil> doesn't this mean that we'll have to get some optimizations in
-      Mach and have the same outside of Mach for translators that access the
-      hardware directly?
-    <braunr> etenil: why ?
-    <etenil> well as you said Mach contains some drivers, but in principle, it
-      shouldn't, translators should do disk access etc, yes?
-    <braunr> etenil: ok
-    <braunr> etenil: so ?
-    <etenil> well, let's say if one were to introduce SATA support in Hurd,
-      nothing would stop him/her to do so with a translator rather than in Mach
-    <braunr> you should avoid the term translator here
-    <braunr> it's really hurd specific
-    <braunr> let's just say a user space task would be responsible for that
-      job, maybe multiple instances of it, yes
-    <etenil> ok, so in this case, let's say we have some I/O optimization
-      techniques like readahead and I/O scheduling within Mach, would these
-      also apply to the user-space task, or would they need to be
-      reimplemented?
-    <braunr> if you have user space drivers, there is no point having I/O
-      scheduling in the kernel
-    <etenil> but we also have drivers within the kernel
-    <braunr> what you call readahead, and I call pagein/out clustering, is
-      really tied to the VM, so it must be in Mach in any case
-    <braunr> well
-    <braunr> you either have one or the other
-    <braunr> currently we have them in the kernel
-    <braunr> if we switch to DDE, we should have all of them outside
-    <braunr> that's why such things must be discussed
-    <etenil> ok so if I follow you, then future I/O device drivers will need to
-      be implemented for Mach
-    <braunr> currently, yes
-    <braunr> but preferrably, someone should continue the work that has been
-      done on DDe so that drivers are outside the kernel
-    <etenil> so for the time being, I will try and improve I/O in Mach, and if
-      drivers ever get out, then some of the I/O optimizations will need to be
-      moved out of Mach
-    <braunr> let me remind you one of the things i said
-    <braunr> i said I/O scheduling should be close to their resource, because
-      we can host several operating systems
-    <braunr> now, the Hurd is the only system running on top of Mach
-    <braunr> so we could just have I/O scheduling outside too
-    <braunr> then you should consider neighbor hurds
-    <braunr> which can use different partitions, but on the same device
-    <braunr> currently, partitions are managed in the kernel, so file systems
-      (and storeio) can't make good scheduling decisions if it remains that way
-    <braunr> but that can change too
-    <braunr> a single storeio representing a whole disk could be shared by
-      several hurd instances, just as if it were a high level driver
-    <braunr> then you could implement I/O scheduling in storeio, which would be
-      an improvement for the current implementation, and reusable for future
-      work
-    <etenil> yes, that was my first instinct
-    <braunr> and you would be mostly free of the kernel internals that make it
-      a nightmare
-    <etenil> but youpi said that it would be better to modify Mach instead
-    <braunr> he mentioned the page clustering thing
-    <braunr> not I/O scheduling
-    <braunr> theseare really two different things
-    <etenil> ok
-    <braunr> you *can't* implement page clustering outside Mach because Mach
-      implements virtual memory
-    <braunr> both policies and mechanisms
-    <etenil> well, I'd rather think of one thing at a time if that's alright
-    <etenil> so what I'm busy with right now is setting up clustered page-in
-    <etenil> which need to be done within Mach
-    <braunr> keep clustered page-outs in mind too
-    <braunr> although there are more constraints on those
-    <etenil> yes
-    <etenil> I've looked up madvise(). There's a lot of documentation about it
-      in Linux but I couldn't find references to it in Mach (nor Hurd), does it
-      exist?
-    <braunr> well, if it did, you wouldn't be caring about clustered page
-      transfers, would you ?
-    <braunr> be careful about linux specific stuff
-    <etenil> I suppose not
-    <braunr> you should implement at least posix options, and if there are
-      more, consider the bsd variants
-    <braunr> (the Mach VM is the ancestor of all modern BSD VMs)
-    <etenil> madvise() seems to be posix
-    <braunr> there are system specific extensions
-    <braunr> be careful
-    <braunr> CONFORMING TO POSIX.1b.   POSIX.1-2001 describes posix_madvise(3)
-      with constants POSIX_MADV_NORMAL, etc., with a behav‐ ior close to that
-      described here.  There is a similar posix_fadvise(2) for file access.
-    <braunr> MADV_REMOVE, MADV_DONTFORK, MADV_DOFORK, MADV_HWPOISON,
-      MADV_MERGEABLE, and MADV_UNMERGEABLE  are  Linux- specific.
-    <etenil> I was about to post these
-    <etenil> ok, so basically madvise() allows tasks etc. to specify a usage
-      type for a chunk of memory, then I could apply the relevant I/O
-      optimization based on this
-    <braunr> that's it
-    <etenil> cool, then I don't need to worry about knowing what the I/O is
-      operating on, I just need to apply the optimizations as advised
-    <etenil> that's convenient
-    <etenil> ok I'll start working on this tonight
-    <etenil> making a basic readahead shouldn't be too hard
-    <braunr> readahead is a misleading name
-    <etenil> is pagein better?
-    <braunr> applies to too many things, doesn't include the case where
-      previous elements could be prefetched
-    <braunr> clustered page transfers is what i would use
-    <braunr> page prefetching maybe
-    <etenil> ok
-    <braunr> you should stick to something that's already used in the
-      literature since you're not inventing something new
-    <etenil> yes I've read a paper about prefetching
-    <etenil> ok
-    <etenil> thanks for your help braunr
-    <braunr> sure
-    <braunr> you're welcome
-    <antrik> braunr: madvise() is really the least important part of the
-      picture...
-    <antrik> very few applications actually use it. but pretty much all
-      applications will profit from clustered paging
-    <antrik> I would consider madvise() an optional goody, not an integral part
-      of the implementation
-    <antrik> etenil: you can find some stuff about KAM's work on
-      http://www.gnu.org/software/hurd/user/kam.html
-    <antrik> not much specific though
-    <etenil> thanks
-    <antrik> I don't remember exactly, but I guess there is also some
-      information on the mailing list. check the archives for last summer
-    <antrik> look for Karim Allah Ahmed
-    <etenil> antrik: I disagree, madvise gives me a good starting point, even
-      if eventually the optimisations should run even without it
-    <antrik> the code he wrote should be available from Google's summer of code
-      page somewhere...
-    <braunr> antrik: right, i was mentioning madvise() because the kernel (VM)
-      interface is pretty similar to the syscall
-    <braunr> but even a default policy would be nice
-    <antrik> etenil: I fear that many bits were discussed only on IRC... so
-      you'd better look through the IRC logs from last April onwards...
-    <etenil> ok
-
-    <etenil> at the beginning I thought I could put that into libstore
-    <etenil> which would have been fine
-
-    <antrik> BTW, I remembered now that KAM's GSoC application should have a
-      pretty good description of the necessary changes... unfortunately, these
-      are not publicly visible IIRC :-(
-
-
-## IRC, freenode, #hurd, 2011-02-16
-
-    <etenil> braunr: I've looked in the kernel to see where prefetching would
-      fit best. We talked of the VM yesterday, but I'm not sure about it. It
-      seems to me that the device part of the kernel makes more sense since
-      it's logically what manages devices, am I wrong?
-    <braunr> etenil: you are
-    <braunr> etenil: well
-    <braunr> etenil: drivers should already support clustered sector
-      read/writes
-    <etenil> ah
-    <braunr> but yes, there must be support in the drivers too
-    <braunr> what would really benefit the Hurd mostly concerns page faults, so
-      the right place is the VM subsystem
-
-[[clustered_page_faults]]
-
-
-# 2012-03
-
-
-## IRC, freenode, #hurd, 2012-03-21
-
-    <mcsim> I thought that readahead should have some heuristics, like
-      accounting size of object and last access time, but i didn't find any in
-      kam's patch. Are heuristics needed or it will be overhead for
-      microkernel? 
-    <youpi> size  of object and last access time are not necessarily useful to
-      take into account
-    <youpi> what would usually typically be kept is the amount of contiguous
-      data that has been read lately
-    <youpi> to know whether it's random or sequential, and how much is read
-    <youpi> (the whole size of the object does not necessarily give any
-      indication of how much of it will be read)
-    <mcsim> if big object is accessed often, performance could be increased if
-      frame that will be read ahead will be increased too.
-    <youpi> yes, but the size of the object really does not matter
-    <youpi> you can just observe how much data is read and realize that it's
-      read a lot
-    <youpi> all the more so with userland fs translators
-    <youpi> it's not because you mount a CD image that you need to read it all
-    <mcsim> youpi: indeed. this will be better. But on other hand there is
-      principle about policy and mechanism. And kernel should implement
-      mechanism, but heuristics seems to be policy. Or in this case moving
-      readahead policy to user level would be overhead?
-    <antrik> mcsim: paging policy is all in kernel anyways; so it makes perfect
-      sense to put the readahead policy there as well
-    <antrik> (of course it can be argued -- probably rightly -- that all of
-      this should go into userspace instead...)
-    <mcsim> antrik: probably defpager partly could do that. AFAIR, it is
-      possible for defpager to return more memory than was asked.
-    <mcsim> antrik: I want to outline what should be done during gsoc. First,
-      kernel should support simple readahead for specified number of pages
-      (regarding direction of access) + simple heuristic for changing frame
-      size. Also default pager could make some analysis, for instance if it has
-      many data located consequentially it could return more data then was
-      asked. For other pagers I won't do anything. Is it suitable?
-    <antrik> mcsim: I think we actually had the same discussion already with
-      KAM ;-)
-    <antrik> for clustered pageout, the kernel *has* to make the decision. I'm
-      really not convinced it makes sense to leave the decision for clustered
-      pagein to the individual pagers
-    <antrik> especially as this will actually complicate matters because a) it
-      will require work in *every* pager, and b) it will probably make handling
-      of MADVISE & friends more complex
-    <antrik> implementing readahead only for the default pager would actually
-      be rather unrewarding. I'm pretty sure it's the one giving the *least*
-      benefit
-    <antrik> it's much, much more important for ext2
-    <youpi> mcsim: maybe try to dig in the irc logs, we discussed about it with
-      neal. the current natural place would be the kernel, because it's the
-      piece that gets the traps and thus knows what happens with each
-      projection, while the backend just provides the pages without knowing
-      which projection wants it. Moving to userland would not only be overhead,
-      but quite difficult
-    <mcsim> antrik: OK, but I'm not sure that I could do it for ext2. 
-    <mcsim> OK, I'll dig.
-
-
-## IRC, freenode, #hurd, 2012-04-01
-
-    <mcsim> as part of implementing of readahead project I have to add
-      interface for setting appropriate behaviour for memory range.  This
-      interface than should be compatible with madvise call, that has a lot of
-      possible advises, but most part of them are specific for Linux (according
-      to man page). Should mach also support these Linux-specific values?
-    <mcsim> p.s. these Linux-specific values shouldn't affect readahead
-      algorithm.
-    <youpi> the interface shouldn't prevent from adding them some day
-    <youpi> so that we don't have to add them yet
-    <mcsim> ok. And what behaviour with value MADV_NORMAL should be look like?
-      Seems that it should be synonym to MADV_SEQUENTIAL, isn't it?
-    <youpi> no, it just means "no idea what it is"
-    <youpi> in the linux implementation, that means some given readahead value
-    <youpi> while SEQUENTIAL means twice as much
-    <youpi> and RANDOM means zero
-    <mcsim> youpi: thank you.
-    <mcsim> youpi: Than, it seems to be better that kernel interface for
-      setting behaviour will accept readahead value, without hiding it behind
-      such constants, like VM_BEHAVIOR_DEFAULT (like it was in kam's
-      patch). And than implementation of madvise will call vm_behaviour_set
-      with appropriate frame size. Is that right?
-    <youpi> question of taste, better ask on the list
-    <mcsim> ok