Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
On systems without a configured swap device, an attempt to launder pages
from a swap object will always fail and result in the page being
reactivated. This means that the page daemon will continuously scan pages
that can never be evicted. With this change, anonymous pages are instead
moved to PQ_UNSWAPPABLE after a failed laundering attempt when no swap
devices are configured. PQ_UNSWAPPABLE is not scanned unless a swap device
is configured, so unreferenced unswappable pages are excluded from the page
daemon's workload.
Reviewed by: alc
As noted in the removed comment, it is possible and not prohibitively
costly to look up the swap blocks for the given page index. Implement
a swap_pager_find_least() function to do that, and use it to iterate
simultaneously over both backing object page queue and swap
allocations when looking for shadowed pages.
Testing shows that number of new succesful scans, enabled by this
addition, is small but non-zero. When worked out, the change both
further reduces the depth of the shadow object chain, and frees unused
but allocated swap and memory.
Suggested and reviewed by: alc
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
configured swap devices in the Linux-compatible format.
Based on the submission by: Robert Millan <rmh debian org>
PR: kern/159281
Reviewed by: bde
Approved by: re (kensmith)
MFC after: 2 weeks
- Restore support for fetching swap information from crash dumps via
kvm_get_swapinfo(3) to fix pstat -T/-s on crash dumps.
Reviewed by: arch@, phk
MFC after: 1 week
Eliminate a lot of checkes to make sure requests are not cross-device
which is unnecessary with the new layout. We know a sequential request
cannot possibly be cross-device because there is a reserved page between
the devices.
Remove a couple of comments which no longer are relevant.
striping to a per device round-robin algorithm.
Because of the policy of not attempting to retain previous swap
allocation on page-out, this means that a newly added swap device
almost instantly takes its 1/N share of the I/O load but it takes
somewhat longer for it to assume it's 1/N share of the pages if there
is plenty of space on the other devices.
Change the 8G total swapspace limitation to 8G per device instead
by using a per device blist rather than one global blist. This
reduces the memory footprint by 75% (typically a couple hundred
kilobytes) for the common case with one swapdevice but NSWAPDEV=4.
Remove the compile time constant limit of number of swap devices,
there is no limit now. Instead of a fixed size array, store the
per swapdev structure in a TAILQ.
Total swap space is still addressed by a 32 bit page number and
therefore the upper limit is now 2^42 bytes = 16TB (for i386).
We still do not allocate the first page of each device in order to
give some amount of protection to any bsdlabel at the start of the
device.
A new device is appended after the existing devices in the swap space,
no attempt is made to fill in holes left behind by swapoff (this can
trivially be changed should it ever become a problem).
The sysctl vm.nswapdev now reflects the number of currently configured
swap devices.
Rename vm_swap_size to swap_pager_avail for consistency with other
exported names.
Change argument type for vm_proc_swapin_all() and swap_pager_isswapped()
to be a struct swdevt pointer rather than an index.
Not changed: we are still using blists to manage the free space,
but since the swapspace is no longer fragmented by the striping
different resource managers might fare better.
the "toss the largest process" emergency handling) from vm_map.c to
swap_pager.c.
The quantity calculated depends strongly on the internals of the
swap_pager and by moving it, we no longer need to expose the
internal metrics of the swap_pager to the world.
paging space and how much of it is in use (in pages).
Use this interface from the Linuxolator instead of groping around in the
internals of the swap_pager.
is not natural and needlessly exposes a lot of dirty laundry.
Move private interfaces between the two from swap_pager.h to swap_pager.c
and staticize as much as possible.
No functional change.
files, so that SWAP_META_PAGES does not vary either.
swap_pager.c ended up with a value of 16, everybody else 8. Go with
the 16 for now.
This should only have any effect in the "kill processes because we
are out of swap" scenario, where it will make some sort of estimate
of something more precise.
style(9)
- Minor space adjustment in cases where we have "( ", " )", if(), return(),
while(), for(), etc.
- Add /* SYMBOL */ after a few #endifs.
Reviewed by: alc
struct swblock entries by dividing the number of the entries by 2
until the swap metadata fits.
- Reject swapon(2) upon failure of swap_zone allocation.
This is just a temporary fix. Better solutions include:
(suggested by: dillon)
o reserving swap in SWAP_META_PAGES chunks, and
o swapping the swblock structures themselves.
Reviewed by: alfred, dillon
in the face of non-stripe-aligned swap areas. The bug could cause a
panic during boot.
Refuse to configure a swap area that is too large (67 GB or so)
Properly document the power-of-2 requirement for SWB_NPAGES.
The patch is slightly different then the one Tor enclosed in the P.R.,
but accomplishes the same thing.
PR: kern/20273
Submitted by: Tor.Egge@fast.no
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.
multiplexed underlying swap devices (/dev/drum). The only thing it did
was to allow root to open /dev/drum, but not do anything with it.
Various utilities used to grovel around in here, but Matt has written
a much nicer (and clean) front-end to this for libkvm, and nothing uses
the old system any more.
The VM system was calling VOP_STRATEGY() on the vp of the first underlying
swap device (not the /dev/drum one, the first real device), and using
the VOP system to indirectly (and only) call swstrategy() to choose
an underlying device and enqueue it on that device. I have changed it
to avoid diverting through the VOP system and to call the only possible
target directly, saving a little bit of time and some complexity.
In all, nothing much changes, except some scaffolding to support the
roundabout way of calling swstrategy() is gone.
Matt gave me the ok to do this some time ago, and I apologize for taking
so long to get around to it.
Swap space can be freed from an interrupt and so swap reservation and
freeing must occur at splvm.
Add swap_pager_reserve() code to support a new swap pre-reservation
capability for the VN device.
Generally cleanup the swap code by simplifying the swp_pager_meta_build()
static function and consolidating the SWAPBLK_NONE test from a bit test
to an absolute compare. The bit test was left over from a rejected
swap allocation scheme that was not ultimately committed. A few other
minor cleanups were also made.
Reorganize the swap strategy code, again for VN support, to not
reallocate swap when writing as this messes up pre-reservation and
can fragment I/O unnecessarily as VN-baesd disk is messed around with.
Reviewed by: Alan Cox <alc@cs.rice.edu>, David Greenman <dg@root.com>
values. The 'int' return value for the procedure was never used and
not well defined in any case when there are mixed errors on pages, so
it has been removed. vm_pager_put_pages() and associated vm_pager
functions now return void.
changes to the VM system to support the new swapper, VM bug
fixes, several VM optimizations, and some additional revamping of the
VM code. The specific bug fixes will be documented with additional
forced commits. This commit is somewhat rough in regards to code
cleanup issues.
Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
deallocation cycles. This should provide a measurable improvement
on swap and memory allocation on loaded systems. It is unlikely a
complete solution. Also, provide more map info with procfs.
Chuck Cranor spurred on this improvement.
have declined due to code-rot over time. The swap pager rundown code
has been clean-up, and unneeded wakeups removed. Lots of splbio's
are changed to splvm's. Also, set the dynamic tunables for the
pageout daemon to be more sane for larger systems (thereby decreasing
the daemon overheadla.)
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
on in the FreeBSD development, I had made a global lock around the
rlist code. This was bogus, and now the lock is maintained on a
per resource list basis. This now allows the rlist code to be used for
almost any non-interrupt level application.
