Add OOM enabler in operator tree #1379
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This commit introduces memory tracker with jemalloc extent hooks which fully works in case when jemalloc config is following:
MALLOC_CONF="retain:false,percpu_arena:percpu,oversize_threshold:1000000000000,muzzy_decay_ms:0,dirty_decay_ms:0" \
./configure \
--disable-cxx \
$COMMON_CONFIGURE_FLAGS \
--with-malloc-conf="retain:false,percpu_arena:percpu,oversize_threshold:1000000000000,muzzy_decay_ms:0,dirty_decay_ms:0"
This config will for jemalloc not to use lazy purge or MADV_FREE(muzzy_decay_ms=0 and dirty_decay_ms=0), it will force jemalloc not to use
custom arena for huge allocations (oversize_threshold) and it will force jemalloc not extend virtual memory indefinitely (retain=false)
and therefore call alloc hook when allocation actually takes place.
Only problem is if we do huge allocations which are not mapped on alloc directly, in that case jemalloc uses cache and we can overcounter
allocation size.
… into improve-memory-tracker
as51340
requested changes
Oct 23, 2023
-> The operator tree goes through all storage methods, so it is common place for all allocations to happen. It seems less error-prone than adding it to each method. |
Josipmrden
approved these changes
Oct 23, 2023
as51340
requested changes
Oct 24, 2023
as51340
approved these changes
Oct 24, 2023
|
RN: @vpavicic : Out of memory exception is now thrown whenever memgraph is out of memory. |
as51340
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that referenced
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Nov 10, 2023
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This diff will introduce the OOM exception enabler to the operator tree.
The reason why OOM enabler was not introduced inside disk storage directly is that exceptions can blow during storing inside
rocksdband the transaction never commits, nor is the exception returned. We need to be careful when to add an OOM Exception enabler, and when to use a blocker in disk storage. Currently, the OOM enabler in the operator tree enables exceptions for all operations.OOM enabler needs to be introduced also in mg_procedure_impl and that is what new diff will do. Currently, if a user specifies multiple threads that will do allocations from the procedure, due to the thread local variable for the OOM enabler to check if the error can be thrown, call in procedure will pass (although it shouldn't if memory is too big) and error will be not thrown.
[master < Task] PR
To keep docs changelog up to date, one more thing to do: