From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964870AbbEHTD2 (ORCPT ); Fri, 8 May 2015 15:03:28 -0400 Received: from mga09.intel.com ([134.134.136.24]:24992 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753306AbbEHS7j (ORCPT ); Fri, 8 May 2015 14:59:39 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,391,1427785200"; d="scan'208";a="692093169" Subject: [PATCH 10/19] x86, mpx: trace ranged MPX operations To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, tglx@linutronix.de, Dave Hansen , dave.hansen@linux.intel.com From: Dave Hansen Date: Fri, 08 May 2015 11:59:52 -0700 References: <20150508185948.4C19F4B0@viggo.jf.intel.com> In-Reply-To: <20150508185948.4C19F4B0@viggo.jf.intel.com> Message-Id: <20150508185952.6913B3F4@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen trace when MPX is zapping pages: When MPX can not free an entire bounds table, it will instead try to zap unused parts of a bounds table to free the backing memory. This decreases RSS (resident set size) without decreasing the virtual space allocated for bounds tables. trace attempts to find bounds tables: This event traces any time we go looking to unmap a bounds table for a given virtual address range. This is useful to ensure that the kernel actually "tried" to free a bounds table versus times it succeeded. It might try and fail if it realized that a table was shared with an adjacent VMA which is not being unmapped. Signed-off-by: Dave Hansen --- b/arch/x86/include/asm/trace/mpx.h | 32 ++++++++++++++++++++++++++++++++ b/arch/x86/mm/mpx.c | 2 ++ 2 files changed, 34 insertions(+) diff -puN arch/x86/include/asm/trace/mpx.h~mpx-trace_unmap_zap arch/x86/include/asm/trace/mpx.h --- a/arch/x86/include/asm/trace/mpx.h~mpx-trace_unmap_zap 2015-05-08 11:46:15.025763624 -0700 +++ b/arch/x86/include/asm/trace/mpx.h 2015-05-08 11:46:15.029763805 -0700 @@ -53,6 +53,38 @@ TRACE_EVENT(bounds_exception_mpx, __entry->bndstatus) ); +DECLARE_EVENT_CLASS(mpx_range_trace, + + TP_PROTO(unsigned long start, + unsigned long end), + TP_ARGS(start, end), + + TP_STRUCT__entry( + __field(unsigned long, start) + __field(unsigned long, end) + ), + + TP_fast_assign( + __entry->start = start; + __entry->end = end; + ), + + TP_printk("[0x%p:0x%p]", + (void *)__entry->start, + (void *)__entry->end + ) +); + +DEFINE_EVENT(mpx_range_trace, mpx_unmap_zap, + TP_PROTO(unsigned long start, unsigned long end), + TP_ARGS(start, end) +); + +DEFINE_EVENT(mpx_range_trace, mpx_unmap_search, + TP_PROTO(unsigned long start, unsigned long end), + TP_ARGS(start, end) +); + #else /* diff -puN arch/x86/mm/mpx.c~mpx-trace_unmap_zap arch/x86/mm/mpx.c --- a/arch/x86/mm/mpx.c~mpx-trace_unmap_zap 2015-05-08 11:46:15.026763669 -0700 +++ b/arch/x86/mm/mpx.c 2015-05-08 11:46:15.030763850 -0700 @@ -668,6 +668,7 @@ static int zap_bt_entries(struct mm_stru len = min(vma->vm_end, end) - addr; zap_page_range(vma, addr, len, NULL); + trace_mpx_unmap_zap(addr, addr+len); vma = vma->vm_next; addr = vma->vm_start; @@ -840,6 +841,7 @@ static int mpx_unmap_tables(struct mm_st long __user *bd_entry, *bde_start, *bde_end; unsigned long bt_addr; + trace_mpx_unmap_search(start, end); /* * "Edge" bounds tables are those which are being used by the region * (start -> end), but that may be shared with adjacent areas. If they _