Attachment 198774 Details for Bug 228768 – lock_delay.patch

[patch] lock_delay.patch

file_228768.txt (text/plain), 1.54 KB, created by John Baldwin on 2018-10-30 17:10:55 UTC

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Creator: John Baldwin

Created: 2018-10-30 17:10:55 UTC

Size: 1.54 KB

patch

obsolete

>Index: sys/kern/kern_mutex.c
>===================================================================
>--- sys/kern/kern_mutex.c	(revision 339923)
>+++ sys/kern/kern_mutex.c	(working copy)
>@@ -1206,7 +1206,7 @@
> 
> 	ldap->spin_cnt++;
> 	if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL)
>-		DELAY(1);
>+		cpu_lock_delay();
> 	else {
> 		td = mtx_owner(m);
> 
>Index: sys/x86/include/x86_var.h
>===================================================================
>--- sys/x86/include/x86_var.h	(revision 339923)
>+++ sys/x86/include/x86_var.h	(working copy)
>@@ -119,6 +119,7 @@
> bool	acpi_get_fadt_bootflags(uint16_t *flagsp);
> void	*alloc_fpusave(int flags);
> void	busdma_swi(void);
>+void	cpu_lock_delay(void);
> bool	cpu_mwait_usable(void);
> void	cpu_probe_amdc1e(void);
> void	cpu_setregs(void);
>Index: sys/x86/x86/delay.c
>===================================================================
>--- sys/x86/x86/delay.c	(revision 339923)
>+++ sys/x86/x86/delay.c	(working copy)
>@@ -110,3 +110,28 @@
> 	init_ops.early_delay(n);
> 	TSEXIT();
> }
>+
>+void
>+cpu_lock_delay(void)
>+{
>+
>+	/*
>+	 * Use TSC to wait for a usec if present, otherwise fall back
>+	 * to reading from port 0x84.  We can't call into timecounters
>+	 * for this delay since timecounters might use spin locks.
>+	 */
>+	if (tsc_freq != 0) {
>+		uint64_t end, freq, now;
>+
>+		sched_pin();
>+		freq = tsc_freq;
>+		now = rdtsc();
>+		end = now + freq / 1000000;
>+		do {
>+			cpu_spinwait();
>+			now = rdtsc();
>+		} while (now < end);
>+		sched_unpin();
>+	} else
>+		inb(0x84);
>+}

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Attachments on bug 228768: 198774