From: Dave Hansen <dave.hansen@intel.com>
To: Simon Liebold <simonlie@amazon.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mark Brown <broonie@kernel.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Helge Deller <deller@gmx.de>,
"Liam R. Howlett" <Liam.Howlett@Oracle.com>,
Simon Liebold <lieboldsimonpaul@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/mm: lower MAP_32BIT begin to reduce heap collisions
Date: Mon, 25 Aug 2025 07:02:37 -0700 [thread overview]
Message-ID: <c69341d2-bf01-48df-9eeb-e346f72c9409@intel.com> (raw)
In-Reply-To: <20250825104847.36669-1-simonlie@amazon.de>
On 8/25/25 03:48, Simon Liebold wrote:
> Commit 03475167fda5 ("x86: Increase brk randomness entropy for 64-bit
> systems") increased the brk randomness from 32 MiB to 1 GiB. MAP_32BIT
> looks between 1 GiB and 2 GiB for an unmapped area. Depending on the
> randomization, a heap starting high enough and being big enough can use
> up all the area that MAP_32BIT looks at, leading to allocation failures.
Isn't that still a really unreasonably gigantic heap?
Would you mind posting some actual /proc/$pid/maps output from one of
the failure cases?
next prev parent reply other threads:[~2025-08-25 14:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-25 10:48 Simon Liebold
2025-08-25 14:02 ` Dave Hansen [this message]
2025-08-26 12:32 ` Simon Liebold
2025-09-12 13:57 ` Simon Liebold
2025-09-12 13:54 Simon Liebold
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