zebra: Prevent starvation in dplane_thread_loop (backport #16224) #16239
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When removing a large number of routes, the linux kernel can take the cpu for an extended amount of time, leaving a situation where FRR detects a starvation event. r1# sharp install routes 10.0.0.0 nexthop 192.168.44.33 1000000 repeat 10 2024-06-14 12:55:49.365 [NTFY] sharpd: [M7Q4P-46WDR] vty[5]@# sharp install routes 10.0.0.0 nexthop 192.168.44.33 1000000 repeat 10 2024-06-14 12:55:49.365 [DEBG] sharpd: [YP4TQ-01TYK] Inserting 1000000 routes 2024-06-14 12:55:57.256 [DEBG] sharpd: [TPHKD-3NYSB] Installed All Items 7.890085 2024-06-14 12:55:57.256 [DEBG] sharpd: [YJ486-NX5R1] Removing 1000000 routes 2024-06-14 12:56:07.802 [WARN] zebra: [QH9AB-Y4XMZ][EC 100663314] STARVATION: task dplane_thread_loop (634377bc8f9e) ran for 7078ms (cpu time 220ms) 2024-06-14 12:56:25.039 [DEBG] sharpd: [WTN53-GK9Y5] Removed all Items 27.783668 2024-06-14 12:56:25.039 [DEBG] sharpd: [YP4TQ-01TYK] Inserting 1000000 routes 2024-06-14 12:56:32.783 [DEBG] sharpd: [TPHKD-3NYSB] Installed All Items 7.743524 2024-06-14 12:56:32.783 [DEBG] sharpd: [YJ486-NX5R1] Removing 1000000 routes 2024-06-14 12:56:41.447 [WARN] zebra: [QH9AB-Y4XMZ][EC 100663314] STARVATION: task dplane_thread_loop (634377bc8f9e) ran for 5175ms (cpu time 179ms) Let's modify the loop in dplane_thread_loop such that after a provider has been run, check to see if the event should yield, if so, stop and reschedule this for the future. Signed-off-by: Donald Sharp <sharpd@nvidia.com> (cherry picked from commit 6faad86)
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When removing a large number of routes, the linux kernel can take the cpu for an extended amount of time, leaving a situation where FRR detects a starvation event.
r1# sharp install routes 10.0.0.0 nexthop 192.168.44.33 1000000 repeat 10 2024-06-14 12:55:49.365 [NTFY] sharpd: [M7Q4P-46WDR] vty[5]@# sharp install routes 10.0.0.0 nexthop 192.168.44.33 1000000 repeat 10 2024-06-14 12:55:49.365 [DEBG] sharpd: [YP4TQ-01TYK] Inserting 1000000 routes 2024-06-14 12:55:57.256 [DEBG] sharpd: [TPHKD-3NYSB] Installed All Items 7.890085 2024-06-14 12:55:57.256 [DEBG] sharpd: [YJ486-NX5R1] Removing 1000000 routes 2024-06-14 12:56:07.802 [WARN] zebra: [QH9AB-Y4XMZ][EC 100663314] STARVATION: task dplane_thread_loop (634377bc8f9e) ran for 7078ms (cpu time 220ms) 2024-06-14 12:56:25.039 [DEBG] sharpd: [WTN53-GK9Y5] Removed all Items 27.783668 2024-06-14 12:56:25.039 [DEBG] sharpd: [YP4TQ-01TYK] Inserting 1000000 routes 2024-06-14 12:56:32.783 [DEBG] sharpd: [TPHKD-3NYSB] Installed All Items 7.743524 2024-06-14 12:56:32.783 [DEBG] sharpd: [YJ486-NX5R1] Removing 1000000 routes 2024-06-14 12:56:41.447 [WARN] zebra: [QH9AB-Y4XMZ][EC 100663314] STARVATION: task dplane_thread_loop (634377bc8f9e) ran for 5175ms (cpu time 179ms)
Let's modify the loop in dplane_thread_loop such that after a provider has been run, check to see if the event should yield, if so, stop and reschedule this for the future.
This is an automatic backport of pull request #16224 done by Mergify.