ghc runtime by default (otherwise depending on a "configure" option)
does memory allocation on their own by first mmapping a 1 TB range of
memory into the process and then parceling out chunks from it.
If one of the chunks is not needed, the kernel needs to be informed -
otherwise the system would quickly run out of available RAM.
ghc does that via madvise(2).
There are two options when doing this informing:
MADV_FREE - Means "I don't need this range or the data in it any more".
Kernel promises to fail later accesses to it.
MADV_DONTNEED - Means "I don't need this range right now - and I don't
need the data in it anymore". Kernel promises to make later accesses to
it succeed (if necessary by providing a new page initialized with zeroes).
MADV_FREE was introduced in Linux 4.5.
glibc 2.25 and later always define MADV_FREE.
Unpatched ghc 8.0.2 will use either MADV_FREE or MADV_DONTNEED, determined
at ghc compile time. Which of them will actually succeed is determined
by the Linux kernel at run time.
This patch makes ghc try MADV_FREE. If it doesn't work, it falls back to
MADV_DONTNEED.
The end result is that ghc programs free their memory with Linux < 4.5 again.
See https://git.haskell.org/ghc.git/commitdiff/6576bf83cdf4eac05eb88a24aa934a736c91e3da for more information.
--- a/rts/posix/OSMem.c
+++ b/rts/posix/OSMem.c
@@ -541,11 +541,24 @@ void osDecommitMemory(void *at, W_ size)
#ifdef MADV_FREE
// Try MADV_FREE first, FreeBSD has both and MADV_DONTNEED
- // just swaps memory out
+ // just swaps memory out. Linux >= 4.5 has both DONTNEED and FREE; either
+ // will work as they both allow the system to free anonymous pages.
+ // It is important that we try both methods as the kernel which we were
+ // built on may differ from the kernel we are now running on.
r = madvise(at, size, MADV_FREE);
-#else
- r = madvise(at, size, MADV_DONTNEED);
+ if(r < 0) {
+ if (errno == EINVAL) {
+ // Perhaps the system doesn't support MADV_FREE; fall-through and
+ // try MADV_DONTNEED.
+ } else {
+ sysErrorBelch("unable to decommit memory");
+ }
+ } else {
+ return;
+ }
#endif
+
+ r = madvise(at, size, MADV_DONTNEED);
if(r < 0)
sysErrorBelch("unable to decommit memory");
}
7fd91003ee089dc0fed35d848e84d0f1'>record.scm
Age | Commit message (Expand) | Author |
2022-11-15 | installer: Report known-unsupported PCI devices....* gnu/installer/hardware.scm: New file.
* gnu/local.mk (INSTALLER_MODULES): Add it.
* po/guix/POTFILES.in: Add it.
* gnu/installer.scm (installer-steps): Pass #:pci-database to the
'welcome' step procedure.
* gnu/installer/newt.scm (welcome-page): Add #:pci-database and pass it
to 'run-welcome-page'.
* gnu/installer/newt/welcome.scm (check-hardware-support): Add #:pci-database.
Enumerate unsupported PCI devices and run an error page when unsupported
devices are found.
(run-welcome-page): Add #:pci-database and pass it to
'check-hardware-support' and to the recursive call.
* gnu/installer/record.scm (<installer>)[welcome-page]: Adjust comment.
* doc/guix.texi (Hardware Considerations): Mention it.
| Ludovic Courtès |
2022-02-02 | installer: Make dump archive creation optional and selective....* gnu/installer.scm (installer-program): Let the installer customize
the dump archive.
* gnu/installer/dump.scm (prepare-dump, make-dump): Split make-dump in
prepare-dump, which copies the files necessary for the dump, and
make-dump which creates the archive.
* gnu/installer/record.scm (installer): Add report-page field. Change
documented return value of exit-error.
* gnu/installer/newt.scm (exit-error): Change arguments to be a string
containing the error. Let the user choose between exiting and
initiating a dump.
(report-page): Add new variable.
* gnu/installer/newt/page.scm (run-dump-page): New variable.
* gnu/installer/newt/dump.scm: Delete it.
Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>
| Josselin Poiret |
2022-02-02 | installer: Add installer-specific run command process....* gnu/installer/record.scm (installer)[run-command]: Add field.
* gnu/installer/utils.scm (run-command-in-installer): Add parameter.
* gnu/installer.scm (installer-program): Parameterize
run-command-in-installer with current installer's run-command.
* gnu/installer/newt.scm (newt-run-command): New variable.
(newt-installer): Use it.
Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>
| Josselin Poiret |
2022-02-02 | installer: Add crash dump upload support....Suggested-by: Josselin Poiret <dev@jpoiret.xyz>
* gnu/installer/dump.scm: New file.
* gnu/installer/newt/dump.scm: New file.
* gnu/local.mk (INSTALLER_MODULES): Add them.
* gnu/installer/record.scm (<installer>)[dump-page]: New field.
* gnu/installer/steps.scm (%current-result): New variable.
(run-installer-steps): Update it.
* gnu/installer.scm (installer-program): Add tar and gip to the installer
path. Add guile-webutils and gnutls to the Guile extensions. Generate and send
the crash dump report.
* gnu/installer/newt.scm (exit-error): Add a report argument. Display the
report id.
(dump-page): New procedure.
(newt-installer): Update it.
| Mathieu Othacehe |
2020-12-11 | install: Discover local substitute servers....* gnu/installer/substitutes.scm: New file.
* gnu/installer/newt/substitutes.scm: New file.
* gnu/local.mk (INSTALLER_MODULES): Add them.
* po/guix/POTFILES.in: Add gnu/installer/newt/substitutes.scm.
* gnu/installer/proxy.scm (with-silent-shepherd): Move to ...
* gnu/installer/utils.scm: ... here.
* gnu/installer/record.scm (<installer>)[substitutes-page]: New field.
* gnu/installer/newt.scm (substitutes-page): New procedure,
(newt-installer): register it.
* gnu/installer.scm (installer-steps): Add "substitutes-page" step.
* gnu/system/install.scm (%installation-services): Add avahi-service-type and
enable substitute server discover in guix-service-type.
[<name-service-switch>]: Set it to %mdns-host-lookup-nss.
| Mathieu Othacehe |