fix: release unused memory in CNetMsgMaker::Make()
#6233
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kwvg
approved these changes
Aug 27, 2024
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How long these objects are alive? And how many of them can be alive at the same time? 4kb doesn't seems as big overhead. |
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@knst, when backporting With additional logging and Clang build:GCC build:This PR shrinks the vector down to size so that memory accounting works like it should and allows for reintroduction of |
The overhead of holding more memory than needed is small indeed and messages are alive only until they are sent so shouldn't be a huge issue from that point of view. The problem is that not releasing unused memory breaks memory accounting like @kwvg mentioned above. Also, |
5 tasks
Could you show how exactly memory is accounting? |
check kwvg@aa3c25d |
knst
reviewed
Aug 30, 2024
| @@ -21,6 +21,7 @@ class CNetMsgMaker | |||
| msg.m_type = std::move(msg_type); | |||
| msg.data.reserve(4 * 1024); | |||
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maybe better to drop reserve then?
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don't think so, check commit message here
knst
approved these changes
Aug 30, 2024
PastaPastaPasta
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Sep 4, 2024
, bitcoin#24021, bitcoin#24543, bitcoin#26844, bitcoin#25325, bitcoin#28165, partial bitcoin#20524, bitcoin#26036, bitcoin#27981 (networking backports: part 7) 76a458e fmt: apply formatting suggestions from `clang-format-diff.py` (Kittywhiskers Van Gogh) 63962ec merge bitcoin#28165: transport abstraction (Kittywhiskers Van Gogh) c6b9186 merge bitcoin#25325: Add pool based memory resource (Kittywhiskers Van Gogh) 8c986d6 partial bitcoin#27981: Fix potential network stalling bug (Kittywhiskers Van Gogh) 13f6dc1 merge bitcoin#26844: Pass MSG_MORE flag when sending non-final network messages (Kittywhiskers Van Gogh) caaa0fd net: use `std::deque` for `vSendMsg` instead of `std::list` (Kittywhiskers Van Gogh) 2ecba6b partial bitcoin#26036: add NetEventsInterface::g_msgproc_mutex (Kittywhiskers Van Gogh) f6c9439 merge bitcoin#24543: Move remaining globals into PeerManagerImpl (Kittywhiskers Van Gogh) dbe41ea refactor: move object request logic to `PeerManagerImpl` (Kittywhiskers Van Gogh) 112c4e0 merge bitcoin#24021: Rename and move PoissonNextSend functions (Kittywhiskers Van Gogh) 6d690ed merge bitcoin#23970: Remove pointless and confusing shift in RelayAddress (Kittywhiskers Van Gogh) 87205f2 merge bitcoin#21327: ignore transactions while in IBD (Kittywhiskers Van Gogh) 51ad8e4 merge bitcoin#21148: Split orphan handling from net_processing into txorphanage (Kittywhiskers Van Gogh) cbff29a partial bitcoin#20524: Move MIN_VERSION_SUPPORTED to p2p.py (Kittywhiskers Van Gogh) Pull request description: ## Additional Information * Dependent on #6098 * Dependent on #6233 * `p2p_ibd_txrelay.py` was first introduced in [bitcoin#19423](bitcoin#19423) to test feefilter logic but on account of Dash not having feefilter capabilities, that backport was skipped over but on account of the tests introduced in [bitcoin#21327](bitcoin#21327) that test capabilities present in Dash, a minimal version of `p2p_ibd_txrelay.py` has been committed in. * `vSendMsg` is originally a `std::deque` and as an optimization, was changed to a `std::list` in 027a852 ([dash#3398](#3398)) but this renders us unable to backport [bitcoin#26844](bitcoin#26844) as it introduces build failures. The optimization has been reverted to make way for the backport. <details> <summary>Compile failure:</summary> ``` net.cpp:959:20: error: invalid operands to binary expression ('iterator' (aka '_List_iterator<std::vector<unsigned char, std::allocator<unsigned char>>>') and 'int') if (it + 1 != node.vSendMsg.end()) { ~~ ^ ~ /usr/bin/../lib/gcc/x86_64-linux-gnu/9/../../../../include/c++/9/bits/stl_bvector.h:303:3: note: candidate function not viable: no known conversion from 'iterator' (aka '_List_iterator<std::vector<unsigned char, std::allocator<unsigned char>>>') to 'ptrdiff_t' (aka 'long') for 1st argument operator+(ptrdiff_t __n, const _Bit_iterator& __x) [...] 1 error generated. make[2]: *** [Makefile:11296: libbitcoin_server_a-net.o] Error 1 make[2]: *** Waiting for unfinished jobs.... make[2]: Leaving directory '/src/dash/src' make[1]: *** [Makefile:19171: all-recursive] Error 1 make[1]: Leaving directory '/src/dash/src' make: *** [Makefile:799: all-recursive] Error 1 ``` </details> * The collection of `CNode` pointers in `CConnman::SocketHandlerConnected` has been changed to a `std::set` to allow for us to erase elements from `vReceivableNodes` if the node is _also_ in the set of sendable nodes and the send hasn't entirely succeeded to avoid a deadlock (i.e. backport [bitcoin#27981](bitcoin#27981)) * When backporting [bitcoin#28165](bitcoin#28165), `denialofservice_tests` has been modified to still check with `vSendMsg` instead of `Transport::GetBytesToSend()` as changes in networking code to support LT-SEMs (level-triggered socket events mode) mean that the message doesn't get shifted from `vSendMsg` to `m_message_to_send`, as the test expects. * Specifically, the changes made for LT-SEM support result in the function responsible for making that shift (`Transport::SetMessageToSend()` through `CConnman::SocketSendData()`), not being called during the test runtime. * As checking `vSendMsg` (directly or through `nSendMsgSize`) isn't enough to determine if the queue is empty, we now also check with `to_send` from `Transport::GetBytesToSend()` to help us make that determination. This mirrors the change present in the upstream backport ([source](https://github.com/bitcoin/bitcoin/pull/28165/files#diff-00021eed586a482abdb09d6cdada1d90115abe988a91421851960e26658bed02R1324-R1327)). ## Breaking Changes * `bandwidth.message.*.bytesSent` will no longer include overhead and will now only report message size as specifics that let us calculate the overhead have been abstracted away. ## Checklist: - [x] I have performed a self-review of my own code - [x] I have commented my code, particularly in hard-to-understand areas **(note: N/A)** - [x] I have added or updated relevant unit/integration/functional/e2e tests - [x] I have made corresponding changes to the documentation **(note: N/A)** - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_ ACKs for top commit: PastaPastaPasta: utACK 76a458e Tree-SHA512: 2e47c207c1f854cfbd5b28c07dd78e12765ddb919abcd7710325df5d253cd0ba4bc30aa21545d88519e8acfe65638a57db4ca66853aca82fc355542210f4b394
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Issue being fixed or feature implemented
We reserve capacity for large messages in
CNetMsgMaker::Make()but most messages are small yet we never release unused memory here. Discovered while debugging 28165 backport issues.What was done?
How Has This Been Tested?
Breaking Changes
n/a
Checklist: