17/10/2025 09:55, Morten Brørup: > > From: Thomas Monjalon [mailto:[email protected]] > > Sent: Friday, 17 October 2025 09.32 > > > > 17/10/2025 00:29, Morten Brørup: > > > > + /* Calculate total allocated mbufs */ > > > > + uint64_t total_allocated = 0; > > > > + for (enum rte_mbuf_history_op op = > > > > RTE_MBUF_HISTORY_OP_LIB_ALLOC; > > > > + op < RTE_MBUF_HISTORY_OP_MAX; op++) > > > > + total_allocated += stats[op]; > > > > > > I might be overly cautious here, but the app (or driver) might have a > > bug, and mark the mbuf with OP_APP_FREE (or OP_PMD_FREE) without > > actually freeing the mbuf back to the mempool. > > > > Yes > > > > > So you should only trust the mempool library (OP_LIB_FREE) to mark > > the mbuf as actually freed. I.e. start the loop at op = > > RTE_MBUF_HISTORY_OP_LIB_FREE. > > > > We cannot because these statistics are about the latest state. > > So if the app marks the mbuf as freed after the library, > > they should be reported as non allocated. > > The app cannot mark the mbuf after calling rte_mbuf_raw_free_bulk(). That > would be a "use after free" bug.
Yes but it can happen :) Anyway there is also the transient of mbuf marked by PMD or app before being marked by the lib. I think in those cases it is expected to consider the mbuf as non-allocated in the stats. > > > The app/driver should eventually call rte_mbuf_raw_free_bulk() or > > similar to release the mbuf back to the mempool. > > > > Because we don't know in which order the mbufs are marked > > in the call stack, we must trust these free ops. > > > > I really think there is room for improvements in the details of the > > marks > > and their usage. I suggest we merge and play with this experimental > > feature, > > and discuss in the next cycle how to improve the markers. > > > > Since it's only a minor detail in the dump function that I'm having minor > doubts about, merging as-is is OK with me. > > It's more important getting the feature included than making it perfect at > its introduction - as you mention yourself: it's an experimental feature. Yes let's play with it, we may discover that the markers should be changed more deeply.
