- The previous magazine ageing sceme relied on the on_each_cpu()
function to call spl_magazine_age() on each cpu. It turns out
this could deadlock with do_flush_tlb_all() which also relies
on the IPI based on_each_cpu(). To avoid this problem a per-
magazine delayed work item is created and indepentantly
scheduled to the correct cpu removing the need for on_each_cpu().
- Additionally two unused fields were removed from the type
spl_kmem_cache_t, they were hold overs from previous cleanup.
- struct work_struct work
- struct timer_list timer
- Default SPL_KMEM_CACHE_DELAY changed to 15 to match Solaris.
- Aged out slab checking occurs every SPL_KMEM_CACHE_DELAY / 3.
- skc->skc_reap tunable added whichs allows callers of
spl_slab_reclaim() to cap the number of slabs reclaimed.
On Solaris all eligible slabs are always reclaimed, and this
is still the default behavior. However, I suspect that is
not always wise for reasons such as in the next comment.
- spl_slab_reclaim() added cond_resched() while walking the
slab/object free lists. Soft lockups were observed when
freeing large numbers of vmalloc'd slabs/objets.
- spl_slab_reclaim() 'sks->sks_ref > 0' check changes from
incorrect 'break' to 'continue' to ensure all slabs are
checked.
- spl_cache_age() reworked to avoid a deadlock with
do_flush_tlb_all() which occured because we slept waiting
for completion in spl_cache_age(). To waiting for magazine
reclamation to finish is not required so we no longer wait.
- spl_magazine_create() and spl_magazine_destroy() shifted
back to using for_each_online_cpu() instead of the
spl_on_each_cpu() approach which was of course a bad idea
due to memory allocations which Ricardo pointed out.
Added support for Solaris swapfs_minfree, and swapfs_reserve tunables.
In additional availrmem is now available and return a reasonable value
which is reasonably analogous to the Solaris meaning. On linux we
return the sun of free and inactive pages since these are all easily
reclaimable.
All tunables are available in /proc/sys/kernel/spl/vm/* and they may
need a little adjusting once we observe the real behavior. Some of
the defaults are mapped to similar linux counterparts, others are
straight from the OpenSolaris defaults.
Support added to provide reasonable values for the global Solaris
VM variables: minfree, desfree, lotsfree, needfree. These values
are set to the sum of their per-zone linux counterparts which
should be close enough for Solaris consumers.
When a non-GPL app links against the SPL we cannot use the udev
interfaces, which means non of the device special files are created.
Because of this I had added a poor mans udev which cause the SPL
to invoke an upcall and create the basic devices when a minor
is registered. When a minor is unregistered we use the vnode
interface to unlink the special file.
- Added SPL_AC_3ARGS_ON_EACH_CPU configure check to determine
if the older 4 argument version of on_each_cpu() should be
used or the new 3 argument version. The retry argument was
dropped in the new API which was never used anyway.
- Updated work queue compatibility wrappers. The old way this
worked was to pass a data point when initialized the workqueue.
The new API assumed the work item is embedding in a structure
and we us container_of() to find that data pointer.
- Updated skc->skc_flags to be an unsigned long which is now
type checked in the bit operations. This silences the warnings.
- Updated autogen products and splat tests accordingly
- Added slab work queue task which gradually ages and free's slabs
from the cache which have not been used recently.
- Optimized slab packing algorithm to ensure each slab contains the
maximum number of objects without create to large a slab.
- Fix deadlock, we can never call kv_free() under the skc_lock. We
now unlink the objects and slabs from the cache itself and attach
them to a private work list. The contents of the list are then
subsequently freed outside the spin lock.
- Move magazine create/destroy operation on to local cpu.
- Further performace optimizations by minimize the usage of the large
per-cache skc_lock. This includes the addition of KMC_BIT_REAPING
bit mask which is used to prevent concurrent reaping, and to defer
new slab creation when reaping is occuring.
- Add KMC_BIT_DESTROYING bit mask which is set when the cache is being
destroyed, this is used to catch any task accessing the cache while
it is being destroyed.
- Add comments to all the functions and additional comments to try
and make everything as clear as possible.
- Major cleanup and additions to the SPLAT kmem tests to more
rigerously stress the cache implementation and look for any problems.
This includes correctness and performance tests.
- Updated portable work queue interfaces
udev support from sunddi implementation because it uses GPL-only
symbols. This support is optionally available for SPL consumers
if they define HAVE_GPL_ONLY_SYMBOLS and license their module as
GPL using the MODULE_LICENSE("GPL") macro.
git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@179 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c
This fixes an oops when unloading the modules, in the case where memory
tracking was enabled and there were memory leaks. The comment in the
code explains what was the problem.
* spl-10-fix-assert-verify-ndebug.patch
This fixes ASSERT*() and VERIFY*() macros in non-debug builds. VERIFY*()
macros are supposed to check the condition and panic even in production
builds, and ASSERT*() macros don't need to evaluate the arguments.
Also some 32-bit fixes.
git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@165 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c
That said when working with a finite resource like memory failure really
is always a possibility. It would be far better longer term if the ZFS
code could be weened off this assumption and properly handle the cases
where an allocation fails. Still I've applied the patch to spl-0.3.4
since this layer is supposed to emulate Solaris as closely as possible.
git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@164 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c
Brian Behlendorf
Ricardo M. Correia
behlendo