Thanks!
On Friday, September 19, 2025 at 4:33:33 AM UTC-4 Ben Noordhuis wrote:

> Yes, 16k on x64 and arm64 android.
>
> On Tue, Sep 16, 2025 at 6:53 PM 'Mati Cohen' via v8-users
> <[email protected]> wrote:
> >
> > I'm willing to recompile the latest stable version. I am looking at 
> build_config.h and for it's using the following implementation:
> >
> > #if (defined(V8_OS_MACOS) && defined(V8_HOST_ARCH_ARM64)) || \
> > (defined(V8_OS_ANDROID) && \
> > (defined(V8_HOST_ARCH_ARM64) || defined(V8_HOST_ARCH_X64))) || \
> > defined(V8_HOST_ARCH_LOONG64) || defined(V8_HOST_ARCH_MIPS64) || \
> > defined(V8_OS_IOS)
> > // Android 64 bit has experimental support for 16kB pages.
> > // MacOS & iOS on arm64 uses 16kB pages.
> > // LOONG64 and MIPS64 also use 16kB pages.
> > constexpr int kMinimumOSPageSize = 16 * 1024;
> > #elif defined(V8_OS_LINUX) && !defined(V8_OS_ANDROID) && \
> > (defined(V8_HOST_ARCH_ARM64) || defined(V8_HOST_ARCH_PPC64))
> > // Linux on arm64 (excluding android) and PPC64 can be configured for up 
> to 64kB
> > // pages.
> > constexpr int kMinimumOSPageSize = 64 * 1024;
> > #else
> > // Everything else uses 4kB pages.
> > constexpr int kMinimumOSPageSize = 4 * 1024;
> > #endif
> >
> > Sorry for my ignorance, but does it mean that all Android devices with 
> arm64-v8a and x86_64 architectures will use a size of 16KB. Is this 
> correct? I am trying to understand if there are devices with arm64-v8a and 
> x86_64 architectures which still use 4KB for page sizes.
> >
> > Thanks,
> > Matias.
> >
> > On Saturday, September 13, 2025 at 7:17:56 AM UTC-4 Ben Noordhuis wrote:
> >>
> >> Assuming recompiling is not a problem for you: just edit
> >> build_config.h and change it to 16k.
> >>
> >> IIRC, stdout and stderr are not normally hooked up to anything on
> >> Android but it should be possible to freopen them to a log file.
> >>
> >> On Fri, Sep 12, 2025 at 4:15 PM 'Matias Cohen' via v8-users
> >> <[email protected]> wrote:
> >> >
> >> > Thanks Ben.
> >> >
> >> > Yeah, that’s strange. I also noticed that SetDataReadOnly didn’t 
> exist in 10.4.132. Moreover, the V8_FATAL exception that is raised was 
> added even later. Maybe my records about 10.4.132 are wrong, but I am sure 
> that we built v8 last time in August 2022, so I can’t explain it.
> >> >
> >> > Android Studio don’t show any error message more than the stacktrace 
> I already shared.
> >> >
> >> > My guess is that kMinimumOSPageSize was still 4KB for Android back 
> then when I built v8 (yet I can’t explain why SetDataReadOnly is part of 
> the stacktrace).
> >> >
> >> > Is there any way for me to overwrite kMinimumOSPageSize from 
> “outside” v8, just to test if that makes a difference?
> >> >
> >> > Thanks!
> >> >
> >> > > On Sep 12, 2025, at 5:20 AM, Ben Noordhuis <[email protected]> 
> wrote:
> >> > >
> >> > > On Fri, Sep 12, 2025 at 8:26 AM 'Mati Cohen' via v8-users
> >> > > <[email protected]> wrote:
> >> > >>
> >> > >> Hi,
> >> > >>
> >> > >> My app is using v8 to run a JS environment. Last time I built v8 
> was about 3 years ago by pointing to 10.4.132.
> >> > >>
> >> > >> As per Google policy, my app needs to support 16 KB page size and 
> I've been checking all my dependencies to meet that criteria.
> >> > >>
> >> > >> Apparently, based on my checks, my v8 build does support it and I 
> managed to run the app on my device.
> >> > >> However, v8 is crashing as soon as I call V8::Initialize(); with 
> the following stack trace:
> >> > >>
> >> > >> /base.apk!liben8.so (offset 0x8ad8000) (v8::base::OS::Abort()+28)
> >> > >> /base.apk!liben8.so (offset 0x8ad8000) (V8_Fatal(char const*, 
> ...)+376)
> >> > >> /base.apk!liben8.so (offset 0x8ad8000) 
> (v8::base::OS::SetDataReadOnly(void*, unsigned long)+52)
> >> > >> /base.apk!liben8.so (offset 0x8ad8000) 
> (v8::internal::V8::Initialize()+1552)
> >> > >> /base.apk!liben8.so (offset 0x8ad8000) (v8::V8::Initialize(int)+28)
> >> > >> /base.apk!liben8.so (offset 0x8ad8000) 
> (Runtime::Runtime(_JNIEnv*)+172)
> >> > >>
> >> > >> As explained at 
> https://www.google.com/url?q=https://developer.android.com/guide/practices/page-sizes%23check-code&source=gmail-imap&ust=1758273654000000&usg=AOvVaw2eBFhXRa0E0P-iWsikoJCW,
>  
> I was trying to look for references to PAGE_SIZE and 4096 to see if I was 
> setting up something wrong, but I didn't find anything.
> >> > >>
> >> > >> Does anyone have any knowledge about this?
> >> > >> Thanks a lot,
> >> > >> Mati
> >> > >
> >> > > V8 doesn't use PAGE_SIZE, it uses sysconf(_SC_PAGESIZE).
> >> > >
> >> > > You mention 10.4.132 but that stack trace is from a different 
> version,
> >> > > isn't it? Because SetDataReadOnly didn't exist back then.
> >> > >
> >> > > It crashes when trying to mprotect(PROT_READ) the command line 
> flags,
> >> > > v8_flags. v8_flags is aligned to kMinimumOSPageSize and that 
> _should_
> >> > > be 16k on Android but you'll want to double-check that. It's defined
> >> > > in src/base/build_config.h.
> >> > >
> >> > > What error message did V8 print?
> >> > >
> >> > > --
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> >> > > 
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