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5c15b3123f
In nginx/wrk benchmark, there's a hung problem with high probability
on case likes that: (client will last several minutes to exit)
server: smc_run nginx
client: smc_run wrk -c 10000 -t 1 http://server
Client hangs with the following backtrace:
0 [ffffa7ce8Of3bbf8] __schedule at ffffffff9f9eOd5f
1 [ffffa7ce8Of3bc88] schedule at ffffffff9f9eløe6
2 [ffffa7ce8Of3bcaO] schedule_timeout at ffffffff9f9e3f3c
3 [ffffa7ce8Of3bd2O] wait_for_common at ffffffff9f9el9de
4 [ffffa7ce8Of3bd8O] __flush_work at ffffffff9fOfeOl3
5 [ffffa7ce8øf3bdfO] smc_release at ffffffffcO697d24 [smc]
6 [ffffa7ce8Of3be2O] __sock_release at ffffffff9f8O2e2d
7 [ffffa7ce8Of3be4ø] sock_close at ffffffff9f8ø2ebl
8 [ffffa7ce8øf3be48] __fput at ffffffff9f334f93
9 [ffffa7ce8Of3be78] task_work_run at ffffffff9flOlff5
10 [ffffa7ce8Of3beaO] do_exit at ffffffff9fOe5Ol2
11 [ffffa7ce8Of3bflO] do_group_exit at ffffffff9fOe592a
12 [ffffa7ce8Of3bf38] __x64_sys_exit_group at ffffffff9fOe5994
13 [ffffa7ce8Of3bf4O] do_syscall_64 at ffffffff9f9d4373
14 [ffffa7ce8Of3bfsO] entry_SYSCALL_64_after_hwframe at ffffffff9fa0007c
This issue dues to flush_work(), which is used to wait for
smc_connect_work() to finish in smc_release(). Once lots of
smc_connect_work() was pending or all executing work dangling,
smc_release() has to block until one worker comes to free, which
is equivalent to wait another smc_connnect_work() to finish.
In order to fix this, There are two changes:
1. For those idle smc_connect_work(), cancel it from the workqueue; for
executing smc_connect_work(), waiting for it to finish. For that
purpose, replace flush_work() with cancel_work_sync().
2. Since smc_connect() hold a reference for passive closing, if
smc_connect_work() has been cancelled, release the reference.
Fixes:
|
||
|---|---|---|
| .. | ||
| af_smc.c | ||
| Kconfig | ||
| Makefile | ||
| smc.h | ||
| smc_cdc.c | ||
| smc_cdc.h | ||
| smc_clc.c | ||
| smc_clc.h | ||
| smc_close.c | ||
| smc_close.h | ||
| smc_core.c | ||
| smc_core.h | ||
| smc_diag.c | ||
| smc_ib.c | ||
| smc_ib.h | ||
| smc_ism.c | ||
| smc_ism.h | ||
| smc_llc.c | ||
| smc_llc.h | ||
| smc_netlink.c | ||
| smc_netlink.h | ||
| smc_netns.h | ||
| smc_pnet.c | ||
| smc_pnet.h | ||
| smc_rx.c | ||
| smc_rx.h | ||
| smc_stats.c | ||
| smc_stats.h | ||
| smc_tracepoint.c | ||
| smc_tracepoint.h | ||
| smc_tx.c | ||
| smc_tx.h | ||
| smc_wr.c | ||
| smc_wr.h | ||