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* bug#59365: make-dynamic-linker-cache OOMs for LLVM 15 on i686-linux
@ 2022-11-18 18:41 Marius Bakke
  2022-11-22  8:42 ` Ludovic Courtès
  0 siblings, 1 reply; 3+ messages in thread
From: Marius Bakke @ 2022-11-18 18:41 UTC (permalink / raw)
  To: 59365

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Hello,

LLVM 15.0.4 fails on i686-linux:

  https://ci.guix.gnu.org/build/1702995/details

Because the 'make-dynamic-linker-cache' phase runs out of memory:

  starting phase `make-dynamic-linker-cache'
  GC Warning: Repeated allocation of very large block (appr. size 268439552):
	May lead to memory leak and poor performance
  GC Warning: Repeated allocation of very large block (appr. size 134221824):
	May lead to memory leak and poor performance
  GC Warning: Repeated allocation of very large block (appr. size 268439552):
  	May lead to memory leak and poor performance
  GC Warning: Failed to expand heap by 285216768 bytes
  GC Warning: Failed to expand heap by 268439552 bytes
  GC Warning: Out of Memory! Heap size: 3620 MiB. Returning NULL!
  Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
  Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
  Warning: Unwind-only out of memory exception; skipping pre-unwind handler.

(excerpt from https://ci.guix.gnu.org/build/1702995/log/raw)

Not sure why this phase uses so much memory.  Ideas?

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* bug#59365: make-dynamic-linker-cache OOMs for LLVM 15 on i686-linux
  2022-11-18 18:41 bug#59365: make-dynamic-linker-cache OOMs for LLVM 15 on i686-linux Marius Bakke
@ 2022-11-22  8:42 ` Ludovic Courtès
  2022-11-22 10:22   ` Maxim Cournoyer
  0 siblings, 1 reply; 3+ messages in thread
From: Ludovic Courtès @ 2022-11-22  8:42 UTC (permalink / raw)
  To: Marius Bakke; +Cc: 59365, Maxim Cournoyer, Greg Hogan

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Hi,

(Cc: Maxim and Greg for LLVM packaging questions below.)

Marius Bakke <marius@gnu.org> skribis:

> LLVM 15.0.4 fails on i686-linux:
>
>   https://ci.guix.gnu.org/build/1702995/details
>
> Because the 'make-dynamic-linker-cache' phase runs out of memory:
>
>   starting phase `make-dynamic-linker-cache'
>   GC Warning: Repeated allocation of very large block (appr. size 268439552):
> 	May lead to memory leak and poor performance
>   GC Warning: Repeated allocation of very large block (appr. size 134221824):
> 	May lead to memory leak and poor performance
>   GC Warning: Repeated allocation of very large block (appr. size 268439552):
>   	May lead to memory leak and poor performance
>   GC Warning: Failed to expand heap by 285216768 bytes
>   GC Warning: Failed to expand heap by 268439552 bytes
>   GC Warning: Out of Memory! Heap size: 3620 MiB. Returning NULL!
>   Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
>   Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
>   Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
>
> (excerpt from https://ci.guix.gnu.org/build/1702995/log/raw)
>
> Not sure why this phase uses so much memory.  Ideas?

Yes: the gremlin.scm code uses ‘file-dynamic-info’, which loads the
whole file in memory.  Ridiculous.

We should instead mmap it (but there are no ‘mmap’ bindings in Guile,
yet) or arrange to load just the relevant parts (we’ll have to check but
maybe ‘file-dynamic-info’ can find everything it needs at the beginning
of a file, the PT_DYNAMIC segment.)

For example, with the patch below, things still appear to be fine with
LLVM:

--8<---------------cut here---------------start------------->8---
scheme@(guix build gremlin)> (file-dynamic-info "/gnu/store/mj14k58lfc88jhcn6va0s2fpwkv3s35c-llvm-13.0.1/lib/libLLVMScalarOpts.so")
$11 = #<<elf-dynamic-info> soname: "libLLVMScalarOpts.so.13" needed: ("libLLVMAggressiveInstCombine.so.13" "libLLVMInstCombine.so.13" "libLLVMTransformUtils.so.13" "libLLVMAnalysis.so.13" "libLLVMCore.so.13" "libLLVMSupport.so.13" "libstdc++.so.6" "libm.so.6" "libgcc_s.so.1" "libc.so.6" "ld-linux-x86-64.so.2") rpath: () runpath: ("/gnu/store/mj14k58lfc88jhcn6va0s2fpwkv3s35c-llvm-13.0.1/lib" "/gnu/store/5h2w4qi9hk1qzzgi1w83220ydslinr4s-glibc-2.33/lib" "/gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib" "/gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/10.3.0/../../..")>
scheme@(guix build gremlin)> (file-dynamic-info "/gnu/store/mj14k58lfc88jhcn6va0s2fpwkv3s35c-llvm-13.0.1/lib/libLLVMX86CodeGen.so.13")
$12 = #<<elf-dynamic-info> soname: "libLLVMX86CodeGen.so.13" needed: ("libLLVMAsmPrinter.so.13" "libLLVMX86Desc.so.13" "libLLVMX86Info.so.13" "libLLVMGlobalISel.so.13" "libLLVMCFGuard.so.13" "libLLVMSelectionDAG.so.13" "libLLVMCodeGen.so.13" "libLLVMTarget.so.13" "libLLVMTransformUtils.so.13" "libLLVMAnalysis.so.13" "libLLVMProfileData.so.13" "libLLVMMC.so.13" "libLLVMCore.so.13" "libLLVMSupport.so.13" "libstdc++.so.6" "libm.so.6" "libgcc_s.so.1" "libc.so.6" "ld-linux-x86-64.so.2") rpath: () runpath: ("/gnu/store/mj14k58lfc88jhcn6va0s2fpwkv3s35c-llvm-13.0.1/lib" "/gnu/store/5h2w4qi9hk1qzzgi1w83220ydslinr4s-glibc-2.33/lib" "/gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib" "/gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/10.3.0/../../..")>
--8<---------------cut here---------------end--------------->8---

We could temporarily delete this phase for all 32-bit builds of LLVM.

But the crux of the problem is that llvm@15 has a single huge shared
library, unlike previous versions:

--8<---------------cut here---------------start------------->8---
$ du -hL  /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/*.so
133M    /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/libLLVM-15.0.4.so
96K     /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/libLTO.so
16K     /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/libRemarks.so
--8<---------------cut here---------------end--------------->8---

(It also has tons of .a files, which shouldn’t be there.)

Is that big LLVM.so due to different build options on our side?  Or is
it a radical upstream change (sounds unlikely, but who knows)?

Thanks,
Ludo’.


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diff --git a/guix/build/gremlin.scm b/guix/build/gremlin.scm
index 2a74d51dd9..8a38dde1eb 100644
--- a/guix/build/gremlin.scm
+++ b/guix/build/gremlin.scm
@@ -250,7 +250,11 @@ (define (file-dynamic-info file)
 info."
   (call-with-input-file file
     (lambda (port)
-      (elf-dynamic-info (parse-elf (get-bytevector-all port))))))
+      (elf-dynamic-info (parse-elf
+                         ;; Read at most 10 MiB in memory, which should be
+                         ;; enough to get the PT_DYNAMIC segment.
+                         ;; TODO: mmap the whole file instead.
+                         (get-bytevector-n port (* 10 (expt 2 20))))))))
 
 (define (file-runpath file)
   "Return the DT_RUNPATH dynamic entry of FILE as a list of strings, or #f if

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* bug#59365: make-dynamic-linker-cache OOMs for LLVM 15 on i686-linux
  2022-11-22  8:42 ` Ludovic Courtès
@ 2022-11-22 10:22   ` Maxim Cournoyer
  0 siblings, 0 replies; 3+ messages in thread
From: Maxim Cournoyer @ 2022-11-22 10:22 UTC (permalink / raw)
  To: Ludovic Courtès; +Cc: 59365, Greg Hogan, Marius Bakke

Hi Ludovic,

Ludovic Courtès <ludo@gnu.org> writes:

> Hi,
>
> (Cc: Maxim and Greg for LLVM packaging questions below.)
>
> Marius Bakke <marius@gnu.org> skribis:
>
>> LLVM 15.0.4 fails on i686-linux:
>>
>>   https://ci.guix.gnu.org/build/1702995/details
>>
>> Because the 'make-dynamic-linker-cache' phase runs out of memory:
>>
>>   starting phase `make-dynamic-linker-cache'
>>   GC Warning: Repeated allocation of very large block (appr. size 268439552):
>> 	May lead to memory leak and poor performance
>>   GC Warning: Repeated allocation of very large block (appr. size 134221824):
>> 	May lead to memory leak and poor performance
>>   GC Warning: Repeated allocation of very large block (appr. size 268439552):
>>   	May lead to memory leak and poor performance
>>   GC Warning: Failed to expand heap by 285216768 bytes
>>   GC Warning: Failed to expand heap by 268439552 bytes
>>   GC Warning: Out of Memory! Heap size: 3620 MiB. Returning NULL!
>>   Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
>>   Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
>>   Warning: Unwind-only out of memory exception; skipping pre-unwind handler.
>>
>> (excerpt from https://ci.guix.gnu.org/build/1702995/log/raw)
>>
>> Not sure why this phase uses so much memory.  Ideas?
>
> Yes: the gremlin.scm code uses ‘file-dynamic-info’, which loads the
> whole file in memory.  Ridiculous.

If it loaded just that file, it should be fine, no?  It weighs 133 MiB,
as you've shown below:

> But the crux of the problem is that llvm@15 has a single huge shared
> library, unlike previous versions:
>
> $ du -hL  /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/*.so
> 133M    /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/libLLVM-15.0.4.so
> 96K     /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/libLTO.so
> 16K     /gnu/store/bgqdvvi7k6l255332rfawgjmn2hpn13r-llvm-15.0.4/lib/libRemarks.so
> (It also has tons of .a files, which shouldn’t be there.)

The static files are needed at least to build the clang runtime.  I had
tried to get rid of them without success.  Perhaps they could be moved
to a "static" output if they're needed only at that time.

> Is that big LLVM.so due to different build options on our side?  Or is
> it a radical upstream change (sounds unlikely, but who knows)?

It's caused by -DLLVM_LINK_LLVM_DYLIB=ON and -DLLVM_BUILD_LLVM_DYLIB=ON,
which is the supported configuration to build a shared library of LLVM
(-DBUILD_SHARED_LIBS=ON is obsolete/deprecated) [0].

It also makes things conveniently easy to link to LLVM; you just need to
link to '-lLLVM', and everything it needs is available.

[0]  https://llvm.org/docs/BuildingADistribution.html#special-notes-for-library-only-distributions

-- 
Thanks,
Maxim




^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-11-22 10:23 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-18 18:41 bug#59365: make-dynamic-linker-cache OOMs for LLVM 15 on i686-linux Marius Bakke
2022-11-22  8:42 ` Ludovic Courtès
2022-11-22 10:22   ` Maxim Cournoyer

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