From mboxrd@z Thu Jan 1 00:00:00 1970 From: rabin@rab.in (Rabin Vincent) Date: Mon, 11 Oct 2010 22:45:55 +0530 Subject: [PATCH 2/2] ftrace - add ftrace function_graph support on ARM In-Reply-To: <20101011082535.GA26355@n2100.arm.linux.org.uk> References: <4B91A39F.8050502@am.sony.com> <20100306201849.GD13262@n2100.arm.linux.org.uk> <20101009193757.GB28183@n2100.arm.linux.org.uk> <20101010220603.GA2723@debian> <20101011082535.GA26355@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Oct 11, 2010 at 1:55 PM, Russell King - ARM Linux wrote: > And now to go back to the original question I asked: What is __irq_entry > used for? It's used to identify when we're inside the interrupt handling path. Depending upon the tracing options ("funcgraph-irqs"), this can be excluded from the trace output. > If it's to identify those functions which can't be traced through because > of the stack layout, that's true of all __exception marked functions - > so we might as well make the linker symbols for irqentry alias the > exception text symbols. > > I see nothing special of just the three functions you mention that warrant > them being handled separately by ftrace. See above. The funcgraph-irqs option is supposed to only affect the interrupt handling path, not all exception handling.