dillon at apollo.backplane.com
Mon Jun 30 09:20:57 PDT 2008
:Is there/ will there be in the future, a tunable that limits HAMMER's
:buffer allocations ???
:I.e. can I tell HAMMER to only use a certain amount of memory and
:let me fill up the rest of available RAM as I please.
:Kaiser Jasse -- Authorized Stealth Oracle
What tunables there are only exist to prevent HAMMER from deadlocking
the system by running the kernel out of memory. There is
vfs.hammer.limit_recs which limits the number of small record
structures HAMMER will allocate (so the M_HAMMER kmalloc pool is not
exhausted), and vfs.hammer.limit.dirtybufspace which limits the number
of buffers HAMMER is allowed to hold in a locked state, so HAMMER
knows when it must do a partial finalization of UNDO data to the
HAMMER actually slaves off of the kernel's own buffer cache buffer
management code, so the kernel decides when HAMMER buffers must be
freed, not HAMMER. All the normal kernel and VM tunables apply.
<dillon at backplane.com>
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