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Subject: RE: [PATCH 1/1] exception/stackdepot: add irqentry section in case
 of STACKDEPOT
Reply-To: maninder1.s@samsung.com
Sender: Maninder Singh <maninder1.s@samsung.com>
From:   Maninder Singh <maninder1.s@samsung.com>
To:     Maninder Singh <maninder1.s@samsung.com>,
        "linux@armlinux.org.uk" <linux@armlinux.org.uk>,
        "catalin.marinas@arm.com" <catalin.marinas@arm.com>,
        "will@kernel.org" <will@kernel.org>,
        "mark.rutland@arm.com" <mark.rutland@arm.com>,
        "joey.gouly@arm.com" <joey.gouly@arm.com>,
        "maz@kernel.org" <maz@kernel.org>,
        "pcc@google.com" <pcc@google.com>,
        "amit.kachhap@arm.com" <amit.kachhap@arm.com>,
        "ryabinin.a.a@gmail.com" <ryabinin.a.a@gmail.com>,
        "dvyukov@google.com" <dvyukov@google.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>
CC:     "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kasan-dev@googlegroups.com" <kasan-dev@googlegroups.com>,
        Vaneet Narang <v.narang@samsung.com>,
        AMIT SAHRAWAT <a.sahrawat@samsung.com>
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Message-ID: <20210906124351epcms5p6020fbfe5f885f1e8834a72784b28d434@epcms5p6>
Date:   Mon, 06 Sep 2021 18:13:51 +0530
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        <CGME20210818071602epcas5p4fecf459638312c95c5d5aaa29e7e983a@epcms5p6>
Precedence: bulk


Hi,

Any inputs on this?

>As of now if CONFIG_FUNCTION_GRAPH_TRACER is disabled some functions
>like gic_handle_irq will not be added in irqentry text section.
> 
>which leads to adding more stacks in stackdepot as frames below IRQ
>will not be filtered with filter_irq_stack() function.
> 
>checked with debug interface for satckdepot:
>https://lkml.org/lkml/2017/11/22/242
> 
>e.g. (ARM)
>stack count 23188 backtrace
> prep_new_page+0x14c/0x160
> get_page_from_freelist+0x1258/0x1350
>...
> __handle_domain_irq+0x1ac/0x4ac
> gic_handle_irq+0x44/0x80
> __irq_svc+0x5c/0x98
> __slab_alloc.constprop.0+0x84/0xac
> __kmalloc+0x31c/0x340
> sf_malloc+0x14/0x18
> 
>and for same _irq_svc there were 25000 calls which was causing
>memory pressure of 2MB more on satckdepot, which will keep increasing.
> 
>Before patch memory consumption on ARM target after 2 hours:
>Memory consumed by Stackdepot:3600 KB
> 
>After change:
>============
>Memory consumed by Stackdepot:1744 KB
> 
> prep_new_page+0x14c/0x160
> get_page_from_freelist+0x2e4/0x1350
>...
> __handle_domain_irq+0x1ac/0x4ac
> gic_handle_irq+0x44/0x80
> 
>^^^^^ no frames below this.
> 
>Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
>Signed-off-by: Vaneet Narang <v.narang@samsung.com>
>---
> arch/arm/include/asm/exception.h   | 2 +-
> arch/arm64/include/asm/exception.h | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
> 
>diff --git a/arch/arm/include/asm/exception.h b/arch/arm/include/asm/exception.h
>index 58e039a851af..3f4534cccc0f 100644
>--- a/arch/arm/include/asm/exception.h
>+++ b/arch/arm/include/asm/exception.h
>@@ -10,7 +10,7 @@
> 
> #include <linux/interrupt.h>
> 
>-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
>+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_STACKDEPOT)
> #define __exception_irq_entry        __irq_entry
> #else
> #define __exception_irq_entry
>diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
>index 339477dca551..ef2581b63405 100644
>--- a/arch/arm64/include/asm/exception.h
>+++ b/arch/arm64/include/asm/exception.h
>@@ -13,7 +13,7 @@
> 
> #include <linux/interrupt.h>
> 
>-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
>+#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_STACKDEPOT)
> #define __exception_irq_entry        __irq_entry
> #else
> #define __exception_irq_entry        __kprobes
>--