From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Noam Postavsky <npostavs@gmail.com>, emacs-devel@gnu.org
Subject: Re: Should use of mallopt depend on DOUG_LEA_MALLOC?
Date: Fri, 13 Dec 2019 10:22:51 -0500 [thread overview]
Message-ID: <jwvblsctfzv.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <83tv6470ko.fsf@gnu.org> (Eli Zaretskii's message of "Fri, 13 Dec 2019 16:38:15 +0200")
>> I also don't really have any idea what the mallopt calls do (that is, I
>> can see in the documentation that they modify such and such parameter of
>> the allocator, but I don't know what that means in practice: faster,
>> slower, less RAM, more RAM, etc).
For those in `init_alloc_once_for_pdumper`, I can't help you.
But the ones conditionalized on `mmap_lisp_allowed_p` are used not as
optimizations but to prevent use of mmap within the malloc
implementation in the two known cases where it can break our
(unportable) assumptions:
- when we use MSB bits for the Lisp_Object tags and hence cannot use all
of the addressable memory for Lisp objects.
[ Hopefully, there are no platforms in this category remaining, but
I don't know this to be the case for sure. ]
- when we're about to do the unexec dump because the unexec code doesn't
handle those mmap'd areas.
Stefan
next prev parent reply other threads:[~2019-12-13 15:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87sgme1ww7.fsf@yantar92-laptop.i-did-not-set--mail-host-address--so-tickle-me>
[not found] ` <83o8x0rl6d.fsf@gnu.org>
[not found] ` <87lfs2mzo8.fsf@yantar92-laptop.i-did-not-set--mail-host-address--so-tickle-me>
[not found] ` <87lfs19shb.fsf@mail.linkov.net>
[not found] ` <87a78gn5k5.fsf@yantar92-laptop.i-did-not-set--mail-host-address--so-tickle-me>
[not found] ` <83sgm8ox3g.fsf@gnu.org>
[not found] ` <87zhgflxmc.fsf@yantar92-laptop.i-did-not-set--mail-host-address--so-tickle-me>
[not found] ` <83lfrzq1s1.fsf@gnu.org>
[not found] ` <87d0d7w3tt.fsf@yantar92-laptop.i-did-not-set--mail-host-address--so-tickle-me>
[not found] ` <83zhgaloc5.fsf@gnu.org>
[not found] ` <87zhg7jmjg.fsf@yantar92-laptop.i-did-not-set--mail-host-address--so-tickle-me>
[not found] ` <83h82ej03y.fsf@gnu.org>
[not found] ` <87r21ick48.fsf@gmail.com>
[not found] ` <83immthovt.fsf@gnu.org>
[not found] ` <87o8wkc50t.fsf@gmail.com>
[not found] ` <83lfrodix4.fsf@gnu.org>
2019-12-13 12:12 ` Should use of mallopt depend on DOUG_LEA_MALLOC? (WAS: bug#38345) Noam Postavsky
2019-12-13 14:38 ` Eli Zaretskii
2019-12-13 15:22 ` Stefan Monnier [this message]
2019-12-13 21:55 ` Should use of mallopt depend on DOUG_LEA_MALLOC? Paul Eggert
2019-12-14 7:59 ` Eli Zaretskii
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