feat(thread): add interrupt mode and FdGroup API wrappers#105
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jr42 wants to merge 2 commits intoopenebs:developfrom
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feat(thread): add interrupt mode and FdGroup API wrappers#105jr42 wants to merge 2 commits intoopenebs:developfrom
jr42 wants to merge 2 commits intoopenebs:developfrom
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This was referenced Apr 12, 2026
Add safe Rust wrappers for SPDK's interrupt mode facility (available since SPDK 24.09) and the fd_group hierarchical event multiplexing API. New Thread methods: - interrupt_mode_enable/is_enabled: global init and query - set_interrupt_mode: per-thread poll/interrupt switching - get_interrupt_fd/get_interrupt_fd_group: access thread event fds New FdGroup struct with RAII lifecycle: - create/wait/nest/unnest: hierarchical event multiplexing - add/add_with_fd_type: fd registration with optional auto-drain New FD_TYPE_EVENTFD constant for auto-draining eventfds in fd_group_wait. These APIs enable custom reactors to sleep in fd_group_wait() instead of busy-polling, reducing CPU usage from ~100% to near-zero when idle. Ref: openebs/mayastor#1745 Signed-off-by: Jeremias Reith <jr42@users.noreply.github.com>
Update SPDK revision to include iSCSI poll group interrupt registration and bdev wait_for_examine periodic poller fix, both required for interrupt mode with custom reactors. Note: temporarily points to jr42/spdk fork until the upstream PR is merged into openebs/spdk, at which point owner should revert to "openebs" and rev/sha256 updated to the merged commit. Depends-On: openebs/spdk PR (iSCSI + bdev interrupt fixes) Signed-off-by: Jeremias Reith <jr42@users.noreply.github.com>
tiagolobocastro
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Apr 14, 2026
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We'll have to merge the dependent PR before this one, I'll try to review it a little later today
| /// fd_type value for eventfds: `fd_group_wait()` auto-drains these | ||
| /// by reading the counter to 0 before invoking the callback. | ||
| /// Matches `SPDK_FD_TYPE_EVENTFD` in `spdk/fd_group.h`. | ||
| pub const FD_TYPE_EVENTFD: u32 = 0x1; |
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We should have access to it, via crate::libspdk::SPDK_FD_TYPE_EVENTFD ?
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| impl Debug for FdGroup { | ||
| fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { | ||
| write!(f, "FdGroup({:p})", self.inner) |
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Is it worth including the owner?
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| impl FdGroup { | ||
| /// Create a new fd_group. | ||
| pub fn create() -> Result<Self, i32> { |
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nit: Should we return nix::Error here? and throughout
Abhinandan-Purkait
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Apr 14, 2026
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Summary
Safe Rust wrappers for SPDK's interrupt mode facility and fd_group
hierarchical event multiplexing API (available since SPDK 24.09),
enabling custom reactors to sleep in
fd_group_wait()instead ofbusy-polling.
New Thread methods:
interrupt_mode_enable()/interrupt_mode_is_enabled(): global init and queryset_interrupt_mode(enable): per-thread poll/interrupt switchingget_interrupt_fd()/get_interrupt_fd_group(): access thread event fdsNew FdGroup struct with RAII lifecycle:
create()/Drop: lifecycle managementwait(timeout): block until events (fd_group_wait)nest(child)/unnest(child): hierarchical event multiplexingadd()/add_with_fd_type(): fd registration with optional auto-drainNew constant:
FD_TYPE_EVENTFD: marks eventfds for auto-draining infd_group_wait()These APIs enable the mayastor reactor to implement interrupt mode,
reducing CPU from ~1000m per core to <300m when idle.
Depends-On: openebs/spdk#70 (iSCSI + bdev interrupt fixes)
Ref: openebs/mayastor#1745
Test plan