Hi Jens, Sorry for the confusion. I'm building for x86 Android, not arm. The issue is that Android x86 does not define __NR_shmget. And the fact that it's hardcoded to 29 in arch-x86.h is causing problems. On x86 Android syscall 29 is actually the sys_pause() function. Therefore, fio compiles but it just pauses when shmget() is called. Thanks, Jason Akers -----Original Message----- From: Jens Axboe [mailto:axboe@xxxxxxxxx] Sent: Friday, April 26, 2013 11:18 AM To: Akers, Jason B Cc: fio@xxxxxxxxxxxxxxx Subject: Re: syscall problem on Android x86 On Fri, Apr 26 2013, Akers, Jason B wrote: > Fio hangs when run on the Android x86 emulator. > > Tracking through, I found that the last call made is shmget() (in init.c - setup_thread_area()). > I believe that the hang is related to the fio syscall implementation for x86. > > os-android.h defines shmget as: syscall(__NR_shmget, __key, __size, > __shmflg); > > In arch-x86.h __NR_shmget is defined to 29. This was added on April 11th (a415b2cc). > > Looking deeper, I see that syscall 29 is actually mapped to pause(). (see SYSCALLS.TXT in bionic/libc) I confirmed that sys_pause() was being called by using a kernel breakpoint. This explains why fio hangs. > > Now the question is: What to do about it? > For some reason shmget is only exposed for Android ARM targets even though it is part of the kernel (system.map) for x86. > > I see two options: > 1. add shmget to SYSCALLS.TXT for x86 and recompile. Remove the hardcoded __NR_shmget from arch-x86.h and put a #error instead to warn others that a kernel patch is necessary for Android x86. > > 2. use a "blessed" shared memory allocation method for Android targets (like ashmem / mmap??) Not sure how difficult it would be to make this work with the existing FIO architecture. > > Any other ideas / thoughts / feedback / suggestions are appreciated. So sounds like you are catching the x86 definition of __NR_shmget which is indeed 29, but you are building on Arm. That sounds pretty weird. The below patch should wire up the right Arm syscalls, but I think you need into why it's claiming to be x86 while it is in fact building for arm. diff --git a/arch/arch-arm.h b/arch/arch-arm.h index 7cd9502..8a7398e 100644 --- a/arch/arch-arm.h +++ b/arch/arch-arm.h @@ -18,6 +18,13 @@ #define __NR_sys_vmsplice 343 #endif +#ifndef __NR_shmget +#define __NR_shmat 305 +#define __NR_shmdt 306 +#define __NR_shmget 307 +#define __NR_shmctl 308 +#endif + #if defined (__ARM_ARCH_4__) || defined (__ARM_ARCH_4T__) \ || defined (__ARM_ARCH_5__) || defined (__ARM_ARCH_5T__) || defined (__ARM_ARCH_5TE__) || defined (__ARM_ARCH_5TEJ__) \ || defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) diff --git a/arch/arch-x86.h b/arch/arch-x86.h index 49e64dd..ce2414d 100644 --- a/arch/arch-x86.h +++ b/arch/arch-x86.h @@ -30,9 +30,10 @@ static inline void do_cpuid(unsigned int *eax, unsigned int *ebx, #endif #ifndef __NR_shmget -#define __NR_shmget 29 -#define __NR_shmat 30 -#define __NR_shmctl 31 +#define __NR_shmget 29 +#define __NR_shmat 30 +#define __NR_shmctl 31 +#define __NR_shmdt 67 #endif #define FIO_HUGE_PAGE 4194304 -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
