| Message ID | 20211124153105.155739-2-alex_y_xu@yahoo.ca (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/2] kbuild: use perl instead of shell to get file size | expand |
> On Nov 24, 2021, at 7:31 AM, Alex Xu (Hello71) <alex_y_xu@yahoo.ca> wrote: > > Otherwise, it allocates 2 GB of memory at once. Even though the majority > of this memory is never touched, the default heuristic overcommit > refuses this request if less than 2 GB of RAM+swap is currently > available. This results in "zstd: error 11 : Allocation error : not > enough memory" and the kernel failing to build. > > When the size is specified, zstd will reduce the memory request > appropriately. For typical kernel sizes of ~32 MB, the largest mmap > request will be reduced to 512 MB, which will succeed on all but the > smallest devices. > > For inputs around this size, --stream-size --no-content-size may > slightly decrease the compressed size, or slightly increase it: > https://github.com/facebook/zstd/issues/2848. > > Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> > --- > scripts/Makefile.lib | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index ca901814986a..c98a82ca38e6 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -466,12 +466,20 @@ quiet_cmd_xzmisc = XZMISC $@ > # single pass, so zstd doesn't need to allocate a window buffer. When streaming > # decompression is used, like initramfs decompression, zstd22 should likely not > # be used because it would require zstd to allocate a 128 MB buffer. > +# > +# --stream-size to reduce zstd memory usage (otherwise zstd -22 --ultra > +# allocates, but does not use, 2 GB) and potentially improve compression. > +# > +# --no-content-size to save three bytes which we do not use (we use size_append). > + > +# zstd --stream-size is only supported since 1.4.4 > +zstd_stream_size = $(shell $(ZSTD) -1c --stream-size=0 --no-content-size </dev/null >/dev/null 2>&1 && printf '%s' '--stream-size=$(total_size) --no-content-size') > > quiet_cmd_zstd = ZSTD $@ > - cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ > + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -19; $(size_append); } > $@ > > quiet_cmd_zstd22 = ZSTD22 $@ > - cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ > + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -22 --ultra; $(size_append); } > $@ > > # ASM offsets > # --------------------------------------------------------------------------- > -- > 2.34.0 > You can add: Tested-by: Nick Terrell <terrelln@fb.com> Reviewed-by: Nick Terrell <terrelln@fb.com> Best, Nick Terrell
On Thu, Nov 25, 2021 at 12:30 AM Alex Xu (Hello71) <alex_y_xu@yahoo.ca> wrote: > > Otherwise, it allocates 2 GB of memory at once. Even though the majority > of this memory is never touched, the default heuristic overcommit > refuses this request if less than 2 GB of RAM+swap is currently > available. This results in "zstd: error 11 : Allocation error : not > enough memory" and the kernel failing to build. > > When the size is specified, zstd will reduce the memory request > appropriately. For typical kernel sizes of ~32 MB, the largest mmap > request will be reduced to 512 MB, which will succeed on all but the > smallest devices. > > For inputs around this size, --stream-size --no-content-size may > slightly decrease the compressed size, or slightly increase it: > https://github.com/facebook/zstd/issues/2848. > > Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> The reason why we need this workaround is just because we do "cat and compress". zstd must allocate a huge memory beforehand since it cannot predict how long the stream it will receive. If zstd is given with a file name, it can fstat it to know its file size and allocate the minimal amount of memory. This is my test. I used 'ulimit' to set the upper limit of the memory the zstd can use. [test steps] # Create a 1kB file $ truncate --size=1k dummy # Set the memory size limit to 10MB $ ulimit -S -v 10240 # Pass the file as a argument; success $ zstd -19 -o dummy.zst dummy dummy : 2.15% ( 1024 => 22 bytes, dummy.zst) # cat and zstd; fail $ cat dummy | zstd -19 > dummy.zst zstd: error 11 : Allocation error : not enough memory # cat and zstd --stream-size; success $ cat dummy | zstd -19 --stream-size=1024 > dummy.zst scripts/Makefile.modinst was written in such a way that zstd can know the file size by itself. cmd_zstd = $(ZSTD) -T0 --rm -f -q $< We cannot rewrite scripts/Makefile.lib in that way because arch/x86/boot/compress/Makefile concatenates two files before compression. And this is the only use-case of this feature. So, I am seriously considering to revert this commit: commit d3dd3b5a29bb9582957451531fed461628dfc834 Author: H. Peter Anvin <hpa@zytor.com> Date: Tue May 5 21:17:15 2009 -0700 kbuild: allow compressors (gzip, bzip2, lzma) to take multiple inputs With that commit reverted, zstd will take a single input file, and we can do "zstd -o <output> <input>". So, I will take some time to investigate that approach. > --- > scripts/Makefile.lib | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index ca901814986a..c98a82ca38e6 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -466,12 +466,20 @@ quiet_cmd_xzmisc = XZMISC $@ > # single pass, so zstd doesn't need to allocate a window buffer. When streaming > # decompression is used, like initramfs decompression, zstd22 should likely not > # be used because it would require zstd to allocate a 128 MB buffer. > +# > +# --stream-size to reduce zstd memory usage (otherwise zstd -22 --ultra > +# allocates, but does not use, 2 GB) and potentially improve compression. > +# > +# --no-content-size to save three bytes which we do not use (we use size_append). > + > +# zstd --stream-size is only supported since 1.4.4 > +zstd_stream_size = $(shell $(ZSTD) -1c --stream-size=0 --no-content-size </dev/null >/dev/null 2>&1 && printf '%s' '--stream-size=$(total_size) --no-content-size') > > quiet_cmd_zstd = ZSTD $@ > - cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ > + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -19; $(size_append); } > $@ > > quiet_cmd_zstd22 = ZSTD22 $@ > - cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ > + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -22 --ultra; $(size_append); } > $@ > > # ASM offsets > # --------------------------------------------------------------------------- > -- > 2.34.0 >
> On Dec 5, 2021, at 2:52 PM, Masahiro Yamada <masahiroy@kernel.org> wrote: > > On Thu, Nov 25, 2021 at 12:30 AM Alex Xu (Hello71) <alex_y_xu@yahoo.ca> wrote: >> >> Otherwise, it allocates 2 GB of memory at once. Even though the majority >> of this memory is never touched, the default heuristic overcommit >> refuses this request if less than 2 GB of RAM+swap is currently >> available. This results in "zstd: error 11 : Allocation error : not >> enough memory" and the kernel failing to build. >> >> When the size is specified, zstd will reduce the memory request >> appropriately. For typical kernel sizes of ~32 MB, the largest mmap >> request will be reduced to 512 MB, which will succeed on all but the >> smallest devices. >> >> For inputs around this size, --stream-size --no-content-size may >> slightly decrease the compressed size, or slightly increase it: >> https://github.com/facebook/zstd/issues/2848. >> >> Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> > > > > > The reason why we need this workaround is just because we do > "cat and compress". zstd must allocate a huge memory beforehand > since it cannot predict how long the stream it will receive. > > If zstd is given with a file name, it can fstat it to know its file size > and allocate the minimal amount of memory. > > > This is my test. > I used 'ulimit' to set the upper limit of the memory the zstd can use. > > > [test steps] > > # Create a 1kB file > $ truncate --size=1k dummy > > # Set the memory size limit to 10MB > $ ulimit -S -v 10240 > > # Pass the file as a argument; success > $ zstd -19 -o dummy.zst dummy > dummy : 2.15% ( 1024 => 22 bytes, dummy.zst) > > # cat and zstd; fail > $ cat dummy | zstd -19 > dummy.zst > zstd: error 11 : Allocation error : not enough memory > > # cat and zstd --stream-size; success > $ cat dummy | zstd -19 --stream-size=1024 > dummy.zst > > > > > scripts/Makefile.modinst was written in such a way > that zstd can know the file size by itself. > > cmd_zstd = $(ZSTD) -T0 --rm -f -q $< > > > We cannot rewrite scripts/Makefile.lib in that way because > arch/x86/boot/compress/Makefile concatenates two files before > compression. And this is the only use-case of this feature. > > So, I am seriously considering to revert this commit: > > commit d3dd3b5a29bb9582957451531fed461628dfc834 > Author: H. Peter Anvin <hpa@zytor.com> > Date: Tue May 5 21:17:15 2009 -0700 > > kbuild: allow compressors (gzip, bzip2, lzma) to take multiple inputs > > > > > With that commit reverted, zstd will take a single input file, > and we can do "zstd -o <output> <input>". > > > So, I will take some time to investigate that approach. This will definitely work from a zstd perspective. All versions of zstd will downsize their memory usage to match the file size. Best, Nick Terrell >> --- >> scripts/Makefile.lib | 12 ++++++++++-- >> 1 file changed, 10 insertions(+), 2 deletions(-) >> >> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib >> index ca901814986a..c98a82ca38e6 100644 >> --- a/scripts/Makefile.lib >> +++ b/scripts/Makefile.lib >> @@ -466,12 +466,20 @@ quiet_cmd_xzmisc = XZMISC $@ >> # single pass, so zstd doesn't need to allocate a window buffer. When streaming >> # decompression is used, like initramfs decompression, zstd22 should likely not >> # be used because it would require zstd to allocate a 128 MB buffer. >> +# >> +# --stream-size to reduce zstd memory usage (otherwise zstd -22 --ultra >> +# allocates, but does not use, 2 GB) and potentially improve compression. >> +# >> +# --no-content-size to save three bytes which we do not use (we use size_append). >> + >> +# zstd --stream-size is only supported since 1.4.4 >> +zstd_stream_size = $(shell $(ZSTD) -1c --stream-size=0 --no-content-size </dev/null >/dev/null 2>&1 && printf '%s' '--stream-size=$(total_size) --no-content-size') >> >> quiet_cmd_zstd = ZSTD $@ >> - cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ >> + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -19; $(size_append); } > $@ >> >> quiet_cmd_zstd22 = ZSTD22 $@ >> - cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ >> + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -22 --ultra; $(size_append); } > $@ >> >> # ASM offsets >> # --------------------------------------------------------------------------- >> -- >> 2.34.0 >> > > > -- > Best Regards > Masahiro Yamada
On Wed, Nov 24, 2021 at 4:30 PM Alex Xu (Hello71) <alex_y_xu@yahoo.ca> wrote: > > Otherwise, it allocates 2 GB of memory at once. Even though the majority > of this memory is never touched, the default heuristic overcommit > refuses this request if less than 2 GB of RAM+swap is currently > available. This results in "zstd: error 11 : Allocation error : not > enough memory" and the kernel failing to build. > > When the size is specified, zstd will reduce the memory request > appropriately. For typical kernel sizes of ~32 MB, the largest mmap > request will be reduced to 512 MB, which will succeed on all but the > smallest devices. > > For inputs around this size, --stream-size --no-content-size may > slightly decrease the compressed size, or slightly increase it: > https://github.com/facebook/zstd/issues/2848. > Hi Alex and Nick T., some questions: Can I apply this patch as a single patch - without patch 1/2? Is there an impact also on the kernel's ZRAM/ZSWAP support plus using ZSTD as (de)comp-algo? Here I have: $ grep -i zstd /boot/config-5.15.7-1-amd64-clang13-lto | egrep -i 'zram|zswap' CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD=y CONFIG_ZSWAP_COMPRESSOR_DEFAULT="zstd" CONFIG_ZRAM_DEF_COMP_ZSTD=y CONFIG_ZRAM_DEF_COMP="zstd" Thanks. Regards, - Sedat - > Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> > --- > scripts/Makefile.lib | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > index ca901814986a..c98a82ca38e6 100644 > --- a/scripts/Makefile.lib > +++ b/scripts/Makefile.lib > @@ -466,12 +466,20 @@ quiet_cmd_xzmisc = XZMISC $@ > # single pass, so zstd doesn't need to allocate a window buffer. When streaming > # decompression is used, like initramfs decompression, zstd22 should likely not > # be used because it would require zstd to allocate a 128 MB buffer. > +# > +# --stream-size to reduce zstd memory usage (otherwise zstd -22 --ultra > +# allocates, but does not use, 2 GB) and potentially improve compression. > +# > +# --no-content-size to save three bytes which we do not use (we use size_append). > + > +# zstd --stream-size is only supported since 1.4.4 > +zstd_stream_size = $(shell $(ZSTD) -1c --stream-size=0 --no-content-size </dev/null >/dev/null 2>&1 && printf '%s' '--stream-size=$(total_size) --no-content-size') > > quiet_cmd_zstd = ZSTD $@ > - cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ > + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -19; $(size_append); } > $@ > > quiet_cmd_zstd22 = ZSTD22 $@ > - cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ > + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -22 --ultra; $(size_append); } > $@ > > # ASM offsets > # --------------------------------------------------------------------------- > -- > 2.34.0 >
On Fri, Dec 17, 2021 at 9:51 AM Sedat Dilek <sedat.dilek@gmail.com> wrote: > > On Wed, Nov 24, 2021 at 4:30 PM Alex Xu (Hello71) <alex_y_xu@yahoo.ca> wrote: > > > > Otherwise, it allocates 2 GB of memory at once. Even though the majority > > of this memory is never touched, the default heuristic overcommit > > refuses this request if less than 2 GB of RAM+swap is currently > > available. This results in "zstd: error 11 : Allocation error : not > > enough memory" and the kernel failing to build. > > > > When the size is specified, zstd will reduce the memory request > > appropriately. For typical kernel sizes of ~32 MB, the largest mmap > > request will be reduced to 512 MB, which will succeed on all but the > > smallest devices. > > > > For inputs around this size, --stream-size --no-content-size may > > slightly decrease the compressed size, or slightly increase it: > > https://github.com/facebook/zstd/issues/2848. > > > > Hi Alex and Nick T., > > some questions: > > Can I apply this patch as a single patch - without patch 1/2? > > Is there an impact also on the kernel's ZRAM/ZSWAP support plus using > ZSTD as (de)comp-algo? > > Here I have: > > $ grep -i zstd /boot/config-5.15.7-1-amd64-clang13-lto | egrep -i 'zram|zswap' > CONFIG_ZSWAP_COMPRESSOR_DEFAULT_ZSTD=y > CONFIG_ZSWAP_COMPRESSOR_DEFAULT="zstd" > CONFIG_ZRAM_DEF_COMP_ZSTD=y > CONFIG_ZRAM_DEF_COMP="zstd" > $ egrep 'stream-size' build-log_5.15.9-1-amd64-clang13-lto.txt 49360: { cat arch/x86/boot/compressed/vmlinux.bin arch/x86/boot/compressed/vmlinux.relocs | zstd --stream-size=53340760 --no-content-size -22 --ultra; printf \130\352 \055\003; } > arch/x86/boot/compressed/vmlinux.bin.zst Tested-by: Sedat Dilek <sedat.dilek@gmail.com> - Sedat - > Thanks. > > Regards, > - Sedat - > > > Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> > > --- > > scripts/Makefile.lib | 12 ++++++++++-- > > 1 file changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib > > index ca901814986a..c98a82ca38e6 100644 > > --- a/scripts/Makefile.lib > > +++ b/scripts/Makefile.lib > > @@ -466,12 +466,20 @@ quiet_cmd_xzmisc = XZMISC $@ > > # single pass, so zstd doesn't need to allocate a window buffer. When streaming > > # decompression is used, like initramfs decompression, zstd22 should likely not > > # be used because it would require zstd to allocate a 128 MB buffer. > > +# > > +# --stream-size to reduce zstd memory usage (otherwise zstd -22 --ultra > > +# allocates, but does not use, 2 GB) and potentially improve compression. > > +# > > +# --no-content-size to save three bytes which we do not use (we use size_append). > > + > > +# zstd --stream-size is only supported since 1.4.4 > > +zstd_stream_size = $(shell $(ZSTD) -1c --stream-size=0 --no-content-size </dev/null >/dev/null 2>&1 && printf '%s' '--stream-size=$(total_size) --no-content-size') > > > > quiet_cmd_zstd = ZSTD $@ > > - cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ > > + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -19; $(size_append); } > $@ > > > > quiet_cmd_zstd22 = ZSTD22 $@ > > - cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ > > + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -22 --ultra; $(size_append); } > $@ > > > > # ASM offsets > > # --------------------------------------------------------------------------- > > -- > > 2.34.0 > >
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index ca901814986a..c98a82ca38e6 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -466,12 +466,20 @@ quiet_cmd_xzmisc = XZMISC $@ # single pass, so zstd doesn't need to allocate a window buffer. When streaming # decompression is used, like initramfs decompression, zstd22 should likely not # be used because it would require zstd to allocate a 128 MB buffer. +# +# --stream-size to reduce zstd memory usage (otherwise zstd -22 --ultra +# allocates, but does not use, 2 GB) and potentially improve compression. +# +# --no-content-size to save three bytes which we do not use (we use size_append). + +# zstd --stream-size is only supported since 1.4.4 +zstd_stream_size = $(shell $(ZSTD) -1c --stream-size=0 --no-content-size </dev/null >/dev/null 2>&1 && printf '%s' '--stream-size=$(total_size) --no-content-size') quiet_cmd_zstd = ZSTD $@ - cmd_zstd = { cat $(real-prereqs) | $(ZSTD) -19; $(size_append); } > $@ + cmd_zstd = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -19; $(size_append); } > $@ quiet_cmd_zstd22 = ZSTD22 $@ - cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) -22 --ultra; $(size_append); } > $@ + cmd_zstd22 = { cat $(real-prereqs) | $(ZSTD) $(zstd_stream_size) -22 --ultra; $(size_append); } > $@ # ASM offsets # ---------------------------------------------------------------------------
Otherwise, it allocates 2 GB of memory at once. Even though the majority of this memory is never touched, the default heuristic overcommit refuses this request if less than 2 GB of RAM+swap is currently available. This results in "zstd: error 11 : Allocation error : not enough memory" and the kernel failing to build. When the size is specified, zstd will reduce the memory request appropriately. For typical kernel sizes of ~32 MB, the largest mmap request will be reduced to 512 MB, which will succeed on all but the smallest devices. For inputs around this size, --stream-size --no-content-size may slightly decrease the compressed size, or slightly increase it: https://github.com/facebook/zstd/issues/2848. Signed-off-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> --- scripts/Makefile.lib | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)