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  1. 04 Dec, 2019 4 commits
  3. 03 Dec, 2019 3 commits
    • Michael Anthony Knyszek's avatar
      runtime: convert page allocator bitmap to sparse array · acf3ff2e
      Michael Anthony Knyszek authored 
      Currently the page allocator bitmap is implemented as a single giant
memory mapping which is reserved at init time and committed as needed.
This causes problems on systems that don't handle large uncommitted
mappings well, or institute low virtual address space defaults as a
memory limiting mechanism.

This change modifies the implementation of the page allocator bitmap
away from a directly-mapped set of bytes to a sparse array in same vein
as mheap.arenas. This will hurt performance a little but the biggest
gains are from the lockless allocation possible with the page allocator,
so the impact of this extra layer of indirection should be minimal.

In fact, this is exactly what we see:
    https://perf.golang.org/search?q=upload:20191125.5

This reduces the amount of mapped (PROT_NONE) memory needed on systems
with 48-bit address spaces to ~600 MiB down from almost 9 GiB. The bulk
of this remaining memory is used by the summaries.

Go processes with 32-bit address spaces now always commit to 128 KiB of
memory for the bitmap. Previously it would only commit the pages in the
bitmap which represented the range of addresses (lowest address to
highest address, even if there are unused regions in that range) used by
the heap.

Updates #35568.
Updates #35451.

Change-Id: I0ff10380156568642b80c366001eefd0a4e6c762
Reviewed-on: https://go-review.googlesource.com/c/go/+/207497
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarAustin Clements <austin@google.com>
Reviewed-by: default avatarCherry Zhang <cherryyz@google.com>
      acf3ff2e
    • Xiangdong Ji's avatar
      cmd/vet: honor analyzer flags when running vet outside $GOROOT/src · 2ac1ca91
      Xiangdong Ji authored 
      Additional vet flags specified by user are discarded if 'go vet'
is invoked outside $GOROOT/src to check a package under $GOROOT
(including those under "vendor" of $GOROOT), fix it by avoiding the
overwriting, the logic of detemining if the package under vetting
comes from $GOROOT remains untouched.

Also checked 'go tool vet <options> <cfg>' and 'go vet <options>
<user pkg>', both worked w./w.o this fix.

Fixes #35837.

Change-Id: I549af7964e40440afd35f2d1971f77eee6f8de34
Reviewed-on: https://go-review.googlesource.com/c/go/+/209498
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarJay Conrod <jayconrod@google.com>
      2ac1ca91
    • Ian Lance Taylor's avatar
      runtime: treat call from runtime as transient in TestDebugCall · 386b1a42
      Ian Lance Taylor authored 
      Fixes #32985

Change-Id: I5d504715dcc92d4f4f560ea2e843d9275f938685
Reviewed-on: https://go-review.googlesource.com/c/go/+/207620
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarBryan C. Mills <bcmills@google.com>
Reviewed-by: default avatarAustin Clements <austin@google.com>
      386b1a42
  5. 02 Dec, 2019 5 commits
  7. 28 Nov, 2019 1 commit
    • Richard Miller's avatar
      runtime: on plan9 don't return substitute address for sysReserve · 8054b135
      Richard Miller authored 
      Plan 9 doesn't have a way to reserve virtual memory, so the
implementation of sysReserve allocates memory space (which won't
be backed with real pages until the virtual pages are referenced).
If the space is then freed with sysFree, it's not returned to
the OS (because Plan 9 doesn't allow shrinking a shared address
space), but it must be cleared to zeroes in case it's reallocated
subsequently.

This interacts badly with the way mallocinit on 64-bit machines
sets up the heap, calling sysReserve repeatedly for a very large
(64MB?) arena with a non-nil address hint, and then freeing the space
again because it doesn't have the expected alignment.  The
repeated clearing of multiple megabytes adds significant startup
time to every go program.

We correct this by restricting sysReserve to allocate memory only
when the caller doesn't provide an address hint.  If a hint is
provided, sysReserve will now return nil instead of allocating memory
at a different address.

Fixes #27744

Change-Id: Iae5a950adefe4274c4bc64dd9c740d19afe4ed1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/207917
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarDavid du Colombier <0intro@gmail.com>
      8054b135
  9. 27 Nov, 2019 10 commits
  11. 26 Nov, 2019 4 commits
  13. 25 Nov, 2019 8 commits
  15. 24 Nov, 2019 1 commit
  17. 23 Nov, 2019 4 commits
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