mirror of
https://github.com/torvalds/linux.git
synced 2026-03-08 03:44:45 +01:00
1bc9a28f07
The legacy printer kthread uses console_lock and __console_flush_and_unlock to flush records to the console. This approach results in the console_lock being held for the entire duration of a flush. This can result in large waiting times for those waiting for console_lock especially where there is a large volume of records or where the console is slow (e.g. serial). This contention is observed during boot, as the call to filp_open in console_on_rootfs will delay progression to userspace until any in-flight flush is completed. Let's instead use console_flush_one_record and release/reacquire the console_lock between records. On a PocketBeagle 2, with the following boot args: "console=ttyS2,9600 initcall_debug=1 loglevel=10" Without this patch: [ 5.613166] +console_on_rootfs/filp_open [ 5.643473] mmc1: SDHCI controller on fa00000.mmc [fa00000.mmc] using ADMA 64-bit [ 5.643823] probe of fa00000.mmc returned 0 after 258244 usecs [ 5.710520] mmc1: new UHS-I speed SDR104 SDHC card at address 5048 [ 5.721976] mmcblk1: mmc1:5048 SD32G 29.7 GiB [ 5.747258] mmcblk1: p1 p2 [ 5.753324] probe of mmc1:5048 returned 0 after 40002 usecs [ 15.595240] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30040000.pruss [ 15.595282] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e010000.watchdog [ 15.595297] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e000000.watchdog [ 15.595437] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30300000.crc [ 146.275961] -console_on_rootfs/filp_open ... and with: [ 5.477122] +console_on_rootfs/filp_open [ 5.595814] mmc1: SDHCI controller on fa00000.mmc [fa00000.mmc] using ADMA 64-bit [ 5.596181] probe of fa00000.mmc returned 0 after 312757 usecs [ 5.662813] mmc1: new UHS-I speed SDR104 SDHC card at address 5048 [ 5.674367] mmcblk1: mmc1:5048 SD32G 29.7 GiB [ 5.699320] mmcblk1: p1 p2 [ 5.705494] probe of mmc1:5048 returned 0 after 39987 usecs [ 6.418682] -console_on_rootfs/filp_open ... ... [ 15.593509] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30040000.pruss [ 15.593551] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e010000.watchdog [ 15.593566] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to e000000.watchdog [ 15.593704] ti_sci_pm_domains 44043000.system-controller:power-controller: sync_state() pending due to 30300000.crc Where I've added a printk surrounding the call in console_on_rootfs to filp_open. Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Andrew Murray <amurray@thegoodpenguin.co.uk> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: John Ogness <john.ogness@linutronix.de> Link: https://patch.msgid.link/20251020-printk_legacy_thread_console_lock-v3-3-00f1f0ac055a@thegoodpenguin.co.uk [pmladek@suse.com: Fixed ordering of variable definition suggested by John.] Signed-off-by: Petr Mladek <pmladek@suse.com> |
||
|---|---|---|
| .. | ||
| .kunitconfig | ||
| braille.c | ||
| braille.h | ||
| console_cmdline.h | ||
| index.c | ||
| internal.h | ||
| Makefile | ||
| nbcon.c | ||
| printk.c | ||
| printk_ringbuffer.c | ||
| printk_ringbuffer.h | ||
| printk_ringbuffer_kunit_test.c | ||
| printk_safe.c | ||
| sysctl.c | ||