lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20100116184642.GA5687@random.random>
Date:	Sat, 16 Jan 2010 19:46:42 +0100
From:	Andrea Arcangeli <aarcange@...hat.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH] register MADV_HUGEPAGE

From: Andrea Arcangeli <aarcange@...hat.com>

In order to allow early shipping transparent hugepage feature enabled
only inside MADV_HUGEPAGE and not globally to diminish the risk of
unexpected performance regressions on non-hypervisor related usages
I'd need this little define registered. This is also to avoid things
like this:

#define MADV_DOFORK	11	    	 /* do inherit across fork */
#define MADV_HWPOISON	100		    /* poison a page for testing */

Picking random number not so nice... and with my proof of concept
patch posted working and boosting performance equally to hugetlbfs but
without its limitations, I think it is a given that eventually KVM
will run inside MADV_HUGEPAGE madvise regions only, so I see a
negligeable risk to pollute the kernel in including this as first bit
of the full patchset.

Signed-off-by: Andrea Arcangeli <aarcange@...hat.com>
---

The rest of the transparent hugepage patchset is very ready for
inclusion too with all cleanups requested and after full handling of
all review on linux-mm so far, with the only exception of khugepaged
that is about to be finished, expect a new submit on linux-mm in a few
days. Then we'll have to plug Mel memory compaction on top of it.

(in addition to the below, /sys/kernel/mm/transparent_hugepage also
has been moved to some other distro specific location to avoid any
possible risk of clashes or confusion with future mainline behavior)

Thanks,
Andrea

diff --git a/include/asm-generic/mman-common.h b/include/asm-generic/mman-common.h
--- a/include/asm-generic/mman-common.h
+++ b/include/asm-generic/mman-common.h
@@ -45,6 +45,8 @@
 #define MADV_MERGEABLE   12		/* KSM may merge identical pages */
 #define MADV_UNMERGEABLE 13		/* KSM may not merge identical pages */
 
+#define MADV_HUGEPAGE	14		/* Worth backing with hugepages */
+
 /* compatibility flags */
 #define MAP_FILE	0
 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ