Date: Wed, 09 Jan 2019 17:54:08 +0000 From: bugzilla-noreply@freebsd.org To: emulation@FreeBSD.org Subject: [Bug 230160] linuxulator doesn't implement madvise(MADV_DONTNEED) correctly Message-ID: <bug-230160-4077-P4O934ncSk@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-230160-4077@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230160 --- Comment #2 from Mark Johnston <markj@FreeBSD.org> --- Yes, we should probably just extend our madvise(2) to implement Linux's MADV_DONTNEED. Some care is needed, as we currently assume that madvise(2) is advisory and so may be ignored for pages in some transient busy state. However, we cannot correctly do this when implementing Linux MADV_DONTNEED for private anonymous memory. I don't really like the idea of having a generic MADV_ZERO. First, Linux MADV_DONTNEED only "zeroes" the page if it belongs to a private mapping. Pages belonging to shared mappings should be handled the same way as FreeBSD's MADV_DONTNEED, from my reading of the man page. So that name would be misleading. Second, I think it's pretty widely agreed that Linux's implementation choice here is a historical mistake. We should emulate it, but I don't think it makes much sense to do so in a generic fashion. I'd just add an undocumented MADV_DONTNEED_LINUX. -- You are receiving this mail because: You are the assignee for the bug.home | help
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