Ihor Solodrai <ihor.solodrai@xxxxxxxxx> wrote: > Done. I pushed the logs to the previously mentioned github branch: > https://github.com/kernel-patches/bpf/commit/699a3bb95e2291d877737438fb641628702fd18f Perfect, thanks. Looking at the last record of /proc/fs/netfs/requests, I see: REQUEST OR REF FL ERR OPS COVERAGE ======== == === == ==== === ========= 00000a98 RA 1 2001 0 0 @0000 2000/2000 So the request of interest is R=00000a98 in the trace. Grepping for that, I see (with a few columns cut out): test_progs-no_a-97: netfs_rreq_ref: R=00000a98 NEW r=1 test_progs-no_a-97: netfs_read: R=00000a98 READAHEAD c=00000000 ni=2ec02f16 s=0 l=2000 sz=17a8 test_progs-no_a-97: netfs_rreq_ref: R=00000a98 GET SUBREQ r=2 test_progs-no_a-97: netfs_sreq: R=00000a98[1] DOWN TERM f=192 s=0 17a8/17a8 s=1 e=0 test_progs-no_a-97: netfs_rreq_ref: R=00000a98 GET WORK r=3 test_progs-no_a-97: netfs_sreq_ref: R=00000a98[1] PUT TERM r=1 test_progs-no_a-97: netfs_rreq_ref: R=00000a98 GET SUBREQ r=4 test_progs-no_a-97: netfs_sreq: R=00000a98[2] ZERO SUBMT f=00 s=17a8 0/858 s=0 e=0 kworker/u8:2-36: netfs_rreq_ref: R=00000a98 SEE WORK r=4 kworker/u8:2-36: netfs_rreq: R=00000a98 RA COLLECT f=2021 kworker/u8:2-36: netfs_sreq: R=00000a98[1] DOWN DSCRD f=92 s=0 17a8/17a8 s=1 e=0 kworker/u8:2-36: netfs_sreq_ref: R=00000a98[1] PUT DONE r=0 kworker/u8:2-36: netfs_sreq: R=00000a98[1] DOWN FREE f=92 s=0 17a8/17a8 s=1 e=0 kworker/u8:2-36: netfs_rreq_ref: R=00000a98 PUT SUBREQ r=3 kworker/u8:2-36: netfs_rreq: R=00000a98 RA COMPLET f=2021 kworker/u8:2-36: netfs_rreq: R=00000a98 RA WAKE-IP f=2021 kworker/u8:2-36: netfs_rreq: R=00000a98 RA DONE f=2001 kworker/u8:2-36: netfs_rreq_ref: R=00000a98 PUT WORK r=2 test_progs-no_a-97: netfs_sreq: R=00000a98[2] ZERO TERM f=102 s=17a8 858/858 s=1 e=0 test_progs-no_a-97: netfs_rreq_ref: R=00000a98 GET WORK r=3 test_progs-no_a-97: netfs_sreq_ref: R=00000a98[2] PUT TERM r=1 test_progs-no_a-97: netfs_rreq_ref: R=00000a98 PUT RETURN r=2 kworker/u8:2-36: netfs_rreq_ref: R=00000a98 SEE WORK r=2 kworker/u8:2-36: netfs_rreq_ref: R=00000a98 PUT WORK r=1 You can see subrequest 1 completes fine, the subrequest is freed and the ref it had on the request is put: netfs_sreq: R=00000a98[1] DOWN FREE f=92 s=0 17a8/17a8 s=1 e=0 netfs_rreq_ref: R=00000a98 PUT SUBREQ r=3 Subrequest 2, however isn't collected: netfs_sreq: R=00000a98[2] ZERO SUBMT f=00 s=17a8 0/858 s=0 e=0 netfs_sreq: R=00000a98[2] ZERO TERM f=102 s=17a8 858/858 s=1 e=0 netfs_sreq_ref: R=00000a98[2] PUT TERM r=1 and the work happens again in kworker/u8:2-36 right at the end: netfs_rreq_ref: R=00000a98 SEE WORK r=2 netfs_rreq_ref: R=00000a98 PUT WORK r=1 but this doesn't do anything. The excess buffer clearance happened in the app thread (test_progs-no_a-97): netfs_sreq: R=00000a98[2] ZERO TERM f=102 s=17a8 858/858 s=1 e=0 > Let me know if I can help with anything else. Can you add some more tracepoints? echo 1 >/sys/kernel/debug/tracing/events/netfs/netfs_collect/enable echo 1 >/sys/kernel/debug/tracing/events/netfs/netfs_collect_sreq/enable echo 1 >/sys/kernel/debug/tracing/events/netfs/netfs_collect_state/enable However, I think I may have spotted the issue: I'm mixing clear_and_wake_up_bit() for NETFS_RREQ_IN_PROGRESS (which will use a common system waitqueue) with waiting on an rreq-specific waitqueue in such as netfs_wait_for_read(). I'll work up a fix patch for that tomorrow. Thanks, David
