search for: config_preempt

...be used as a last > > resort, though. > > Actually, it only checks for in_interrupt(). You are right. I have misremembered. You have made me look (thanks) ... > If you call vfree() under > a spinlock, you're in trouble. in_atomic() only knows if we hold a > spinlock for CONFIG_PREEMPT, so it's not safe to check for in_atomic() > in __vfree(). So we need the warning in order that preempt people can > tell those without that there is a bug here. ... Unless I am missing something in_interrupt depends on preempt_count() as well so neither of the two is reliable without P...

...be used as a last > > resort, though. > > Actually, it only checks for in_interrupt(). You are right. I have misremembered. You have made me look (thanks) ... > If you call vfree() under > a spinlock, you're in trouble. in_atomic() only knows if we hold a > spinlock for CONFIG_PREEMPT, so it's not safe to check for in_atomic() > in __vfree(). So we need the warning in order that preempt people can > tell those without that there is a bug here. ... Unless I am missing something in_interrupt depends on preempt_count() as well so neither of the two is reliable without P...

...N > >>> help > >>> This option reduces the latency of the kernel by making > >>> all kernel code (that is not executing in a critical section) > >>> > >>> > > > > Oh, so that's why it doesn't break when CONFIG_PREEMPT=y. > In which case > > that preempt_disable() I spotted is wrong-and-unneeded. > > > > Why doesn't Xen work with preemption?? > > > > I've forgotten the details. Ian? Keir? Steven? Maybe it > can be done. With CONFIG_PREEMPT, we can have preem...

...N > >>> help > >>> This option reduces the latency of the kernel by making > >>> all kernel code (that is not executing in a critical section) > >>> > >>> > > > > Oh, so that's why it doesn't break when CONFIG_PREEMPT=y. > In which case > > that preempt_disable() I spotted is wrong-and-unneeded. > > > > Why doesn't Xen work with preemption?? > > > > I've forgotten the details. Ian? Keir? Steven? Maybe it > can be done. With CONFIG_PREEMPT, we can have preem...

...N > >>> help > >>> This option reduces the latency of the kernel by making > >>> all kernel code (that is not executing in a critical section) > >>> > >>> > > > > Oh, so that's why it doesn't break when CONFIG_PREEMPT=y. > In which case > > that preempt_disable() I spotted is wrong-and-unneeded. > > > > Why doesn't Xen work with preemption?? > > > > I've forgotten the details. Ian? Keir? Steven? Maybe it > can be done. With CONFIG_PREEMPT, we can have preem...

Btw., another question that made me wonder already when doing the original patch: why is it that x86-64 properly uses locking for mm_pin_all(), yet i386 doesn''t need to? Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel

On Wed, Jun 17, 2020 at 01:31:57PM +0200, Michal Hocko wrote: > On Wed 17-06-20 04:08:20, Matthew Wilcox wrote: > > If you call vfree() under > > a spinlock, you're in trouble. in_atomic() only knows if we hold a > > spinlock for CONFIG_PREEMPT, so it's not safe to check for in_atomic() > > in __vfree(). So we need the warning in order that preempt people can > > tell those without that there is a bug here. > > ... Unless I am missing something in_interrupt depends on preempt_count() as > well so neither of the...

Hello, I am trying to build a custom kernel 2.6.24 from ubuntu with xen dom0 support. Does Xen support a tickless system (CONFIG_TICK_ONESHOT=y) and the realtime features of this kernel (CONFIG_PREEMPT=Y instead of CONFIG_PREEMP_VOLUNTARY)? Everytime, I set these options while configuring the kernel, the two settings are not regarded during kernel compilation. I also tried to build the kernel 2.6.27 from OpenSuse 11. The behaviour is similar. If I choose xen-compatible=y in menu entry "...

Hi Xiantao, I general I think the code in this patch is fine. I have a couple of nit-picking comments: > + if (target_mask&0x1) { The formatting here isn't quite what most of the kernel does. It would be better if you added spaces so it's a little easier to read, ie: if (target_mask & 0x1) { > + p = &__per_cpu_idtrs[cpu][0][0]; > + for (i = IA64_TR_ALLOC_BASE;

Hi Xiantao, I general I think the code in this patch is fine. I have a couple of nit-picking comments: > + if (target_mask&0x1) { The formatting here isn't quite what most of the kernel does. It would be better if you added spaces so it's a little easier to read, ie: if (target_mask & 0x1) { > + p = &__per_cpu_idtrs[cpu][0][0]; > + for (i = IA64_TR_ALLOC_BASE;

...y ideas? Which kernel options are required for Asterisk to function properly. Any recommendations on that? Several options do come to mind like, also to prevent timing problems like: - HPET Timer Support (CONFIG_HPET_TIMER) - Provide RTC interrupt (CONFIG_HPET_EMULATE_RTC) - Preemptible Kernel (CONFIG_PREEMPT) (even though the info in kernel describes this for desktop) - Message Signaled Interrupts (MSI and MSI-X) (CONFIG_PCI_MSI) - Enhanced Real Time Clock Support (CONFIG_RTC) - HPET - High Precision Event Timer (CONFIG_HPET) For general Astrisk with ISDN operation: Is telephony support and ISDN su...

On Tue 16-06-20 17:37:11, Matthew Wilcox wrote: > On Wed, Jun 17, 2020 at 01:01:30AM +0200, David Sterba wrote: > > On Tue, Jun 16, 2020 at 11:53:50AM -0700, Joe Perches wrote: > > > On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote: > > > > v4: > > > > - Break out the memzero_explicit() change as suggested by Dan Carpenter > > > > so

On Tue 16-06-20 17:37:11, Matthew Wilcox wrote: > On Wed, Jun 17, 2020 at 01:01:30AM +0200, David Sterba wrote: > > On Tue, Jun 16, 2020 at 11:53:50AM -0700, Joe Perches wrote: > > > On Mon, 2020-06-15 at 21:57 -0400, Waiman Long wrote: > > > > v4: > > > > - Break out the memzero_explicit() change as suggested by Dan Carpenter > > > > so

Hi. I rewrote the patch according to the comments. I adopted generating in-place code because it looks the quickest way. The point Eddie wanted to discuss is how to generate code and its ABI. i.e. in-place generating v.s. direct jump v.s. indirect function call Indirect function call doesn't make sense because ivt.S is compiled multi times. And it is up to pv instances to choose in-place

Hi. I rewrote the patch according to the comments. I adopted generating in-place code because it looks the quickest way. The point Eddie wanted to discuss is how to generate code and its ABI. i.e. in-place generating v.s. direct jump v.s. indirect function call Indirect function call doesn't make sense because ivt.S is compiled multi times. And it is up to pv instances to choose in-place

...esc.h> #include "irq_vectors.h" +#include "mach_asm.h" /* We do not recover from a stack overflow, but at least * we know it happened and should be able to track it down. */ @@ -88,7 +89,7 @@ NT_MASK = 0x00004000 VM_MASK = 0x00020000 #ifdef CONFIG_PREEMPT -#define preempt_stop cli +#define preempt_stop CLI #else #define preempt_stop #define resume_kernel restore_nocheck @@ -161,7 +162,7 @@ ret_from_intr: testl $(VM_MASK | 3), %eax jz resume_kernel ENTRY(resume_userspace) - cli # make sure we don't miss an interrupt + CLI # mak...

...esc.h> #include "irq_vectors.h" +#include "mach_asm.h" /* We do not recover from a stack overflow, but at least * we know it happened and should be able to track it down. */ @@ -88,7 +89,7 @@ NT_MASK = 0x00004000 VM_MASK = 0x00020000 #ifdef CONFIG_PREEMPT -#define preempt_stop cli +#define preempt_stop CLI #else #define preempt_stop #define resume_kernel restore_nocheck @@ -161,7 +162,7 @@ ret_from_intr: testl $(VM_MASK | 3), %eax jz resume_kernel ENTRY(resume_userspace) - cli # make sure we don't miss an interrupt + CLI # mak...

...ce the last series include: 1) Switch to using CPUID 0x40000000 instead of using MSR writes to discover shared memory area 2) Attempt to deal with SMP guests 3) Support for generic CR read caching 4) Support for batching of MMU operations Some known issues: 1) Not really sure what is needed for CONFIG_PREEMPT support. I'm not sure which paravirt_ops calls are actually re-entrant. 2) The paravirt_ops implementation is registered with core_initcall(). However, the paravirt_ops banner is also printed with core_initcall() so that fact that this works now is just the luck of build order. Need a be...

...ce the last series include: 1) Switch to using CPUID 0x40000000 instead of using MSR writes to discover shared memory area 2) Attempt to deal with SMP guests 3) Support for generic CR read caching 4) Support for batching of MMU operations Some known issues: 1) Not really sure what is needed for CONFIG_PREEMPT support. I'm not sure which paravirt_ops calls are actually re-entrant. 2) The paravirt_ops implementation is registered with core_initcall(). However, the paravirt_ops banner is also printed with core_initcall() so that fact that this works now is just the luck of build order. Need a be...

...000 -0800 @@ -48,6 +48,7 @@ #include <asm/smp.h> #include <asm/page.h> #include <asm/desc.h> +#include <mach_asm.h> #include "irq_vectors.h" #define nr_syscalls ((syscall_table_size)/4) @@ -76,7 +77,7 @@ NT_MASK = 0x00004000 VM_MASK = 0x00020000 #ifdef CONFIG_PREEMPT -#define preempt_stop cli +#define preempt_stop CLI #else #define preempt_stop #define resume_kernel restore_nocheck @@ -148,7 +149,7 @@ ret_from_intr: testl $(VM_MASK | 3), %eax jz resume_kernel ENTRY(resume_userspace) - cli # make sure we don't miss an interrupt + CLI # mak...