From: Qiaowei Ren <qiaowei.ren@intel.com>
To: "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@intel.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Qiaowei Ren <qiaowei.ren@intel.com>
Subject: [PATCH v7 01/10] x86, mpx: introduce VM_MPX to indicate that a VMA is MPX specific
Date: Mon, 21 Jul 2014 13:38:35 +0800 [thread overview]
Message-ID: <1405921124-4230-2-git-send-email-qiaowei.ren@intel.com> (raw)
In-Reply-To: <1405921124-4230-1-git-send-email-qiaowei.ren@intel.com>
MPX-enabled application will possibly create a lot of bounds tables
in process address space to save bounds information. These tables
can take up huge swaths of memory (as much as 80% of the memory on
the system) even if we clean them up aggressively. Being this huge,
we need a way to track their memory use. If we want to track them,
we essentially have two options:
1. walk the multi-GB (in virtual space) bounds directory to locate
all the VMAs and walk them
2. Find a way to distinguish MPX bounds-table VMAs from normal
anonymous VMAs and use some existing mechanism to walk them
We expect (1) will be prohibitively expensive. For (2), we only
need a single bit, and we've chosen to use a VM_ flag. We understand
that they are scarce and are open to other options.
There is one potential hybrid approach: check the bounds directory
entry for any anonymous VMA that could possibly contain a bounds table.
This is less expensive than (1), but still requires reading a pointer
out of userspace for every VMA that we iterate over.
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
---
fs/proc/task_mmu.c | 1 +
include/linux/mm.h | 2 ++
2 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index cfa63ee..b2bc755 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -549,6 +549,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
[ilog2(VM_GROWSDOWN)] = "gd",
[ilog2(VM_PFNMAP)] = "pf",
[ilog2(VM_DENYWRITE)] = "dw",
+ [ilog2(VM_MPX)] = "mp",
[ilog2(VM_LOCKED)] = "lo",
[ilog2(VM_IO)] = "io",
[ilog2(VM_SEQ_READ)] = "sr",
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e03dd29..44c75d7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -127,6 +127,8 @@ extern unsigned int kobjsize(const void *objp);
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
+/* MPX specific bounds table or bounds directory (x86) */
+#define VM_MPX 0x02000000
#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */
#ifdef CONFIG_MEM_SOFT_DIRTY
--
1.7.1
--
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next prev parent reply other threads:[~2014-07-21 5:42 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-21 5:38 [PATCH v7 00/10] Intel MPX support Qiaowei Ren
2014-07-21 5:38 ` Qiaowei Ren [this message]
2014-07-21 5:38 ` [PATCH v7 02/10] x86, mpx: add MPX specific mmap interface Qiaowei Ren
2014-07-21 5:38 ` [PATCH v7 03/10] x86, mpx: add macro cpu_has_mpx Qiaowei Ren
2014-07-22 16:18 ` Dave Hansen
2014-07-23 2:35 ` Ren, Qiaowei
2014-07-23 16:02 ` Dave Hansen
2014-07-24 0:56 ` Ren, Qiaowei
2014-07-24 4:46 ` Dave Hansen
2014-07-24 5:23 ` Ren, Qiaowei
2014-07-21 5:38 ` [PATCH v7 04/10] x86, mpx: hook #BR exception handler to allocate bound tables Qiaowei Ren
2014-07-21 5:38 ` [PATCH v7 05/10] x86, mpx: extend siginfo structure to include bound violation information Qiaowei Ren
2014-07-22 0:42 ` Zhang, Tianfei
2014-07-21 5:38 ` [PATCH v7 06/10] mips: sync struct siginfo with general version Qiaowei Ren
2014-07-21 5:38 ` [PATCH v7 07/10] x86, mpx: decode MPX instruction to get bound violation information Qiaowei Ren
2014-07-21 6:07 ` Andi Kleen
2014-07-21 6:11 ` Ren, Qiaowei
2014-07-21 5:38 ` [PATCH v7 08/10] x86, mpx: add prctl commands PR_MPX_REGISTER, PR_MPX_UNREGISTER Qiaowei Ren
2014-07-21 6:09 ` Andi Kleen
2014-10-13 17:41 ` Dave Hansen
2014-10-14 1:44 ` Ren, Qiaowei
2014-07-23 16:20 ` Dave Hansen
2014-07-21 5:38 ` [PATCH v7 09/10] x86, mpx: cleanup unused bound tables Qiaowei Ren
2014-07-22 0:50 ` Zhang, Tianfei
2014-07-23 16:38 ` Dave Hansen
2014-07-24 0:49 ` Ren, Qiaowei
2014-07-24 1:04 ` Dave Hansen
2014-07-24 1:27 ` Ren, Qiaowei
2014-07-21 5:38 ` [PATCH v7 10/10] x86, mpx: add documentation on Intel MPX Qiaowei Ren
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