linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
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

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1405921124-4230-2-git-send-email-qiaowei.ren@intel.com \
    --to=qiaowei.ren@intel.com \
    --cc=dave.hansen@intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mingo@redhat.com \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).