From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 68B7319DF4A; Thu, 4 Jul 2024 08:03:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720080237; cv=none; b=L6tIbouynOnloTNxtWT4JnhLl8jP7KMGczRZ3mZc9whwJF0k6QUFErZANqRfRmzS82Qy5v3MMPxSetwgpKrNG/KQV0Mktlqq8BZJRijLCvV4uSCPN7IcOp3w1fVvduyjrth7wL+Dokc6Ft+xZLTs54MG2KQue5Dz0fR+ntUO5MU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720080237; c=relaxed/simple; bh=aDXIoP7Qs12jneertwpAFgLP48rHuOyLUROrrqS1EyA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fBFsiaiV58VJ+C2/hDrSg6qcPP+Fp/48X7BVyQY2c6An1mEfxoUeDErp6tx3IyshcoXtY4nigDkskToxCRdlY1mSif4xcgqtWluOJxghTQknXTV9sAooQ3N5yJI0zjAPw5bBV7daNqqh6CaMeME8wNOe3D4si/cRLoFXcMhTFiM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ixZyUk/0; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ixZyUk/0" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=MAAslofSIU4T+suArmk0tqr6lMI/BMFkYGLdd/CxpD4=; b=ixZyUk/0xaMLNkaPkhYzRkC4Ra oKbTHlYjTGM5weGvibTXBbrVUJuO7kxbHzpz6v1o+96YdpFFmafYiDGSXDQk2pV6qXtzl2W2nvnHM hlmbmBFFeBbQ9jddPcIseCHBB7bmElFT0UDfb3Tj/pDi7oCiJH99hC2D0twK52r4atAjwIHNKfVSI an2pV54yl7etNI+2RavhNX3jSqX9RtqEFToASc7vu3k2tWP24hKF+WIA0w4+2RGeZgud2oXlMxJWc FmlIZlz35L4YnBp1Ypkm1GOI9mB1CMXCNt+QXvprFaQ8BobGATvLQWykyju737YsPSGRYa5jQ0inY 6JOZjwNw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1sPHRU-00000002dFS-2wQY; Thu, 04 Jul 2024 08:03:48 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 5651B3003FF; Thu, 4 Jul 2024 10:03:48 +0200 (CEST) Date: Thu, 4 Jul 2024 10:03:48 +0200 From: Peter Zijlstra To: Andrii Nakryiko Cc: Andrii Nakryiko , linux-trace-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, oleg@redhat.com, mingo@redhat.com, bpf@vger.kernel.org, jolsa@kernel.org, paulmck@kernel.org, clm@meta.com Subject: Re: [PATCH v2 04/12] uprobes: revamp uprobe refcounting and lifetime management Message-ID: <20240704080348.GP11386@noisy.programming.kicks-ass.net> References: <20240701223935.3783951-1-andrii@kernel.org> <20240701223935.3783951-5-andrii@kernel.org> <20240703133608.GO11386@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Jul 03, 2024 at 01:47:23PM -0700, Andrii Nakryiko wrote: > Your innocuous "// XXX amortize / batch" comment below is *the major > point of this patch set*. Try to appreciate that. It's not a small > todo, it took this entire patch set to allow for that. Tada! diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 354cab634341..c9c9ec87ab9a 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -115,7 +115,8 @@ extern int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); extern int uprobe_register_refctr(struct inode *inode, loff_t offset, loff_t ref_ctr_offset, struct uprobe_consumer *uc); extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool); -extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc); +#define URF_NO_SYNC 0x01 +extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, unsigned int flags); extern int uprobe_mmap(struct vm_area_struct *vma); extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end); extern void uprobe_start_dup_mmap(void); @@ -165,7 +166,7 @@ uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, boo return -ENOSYS; } static inline void -uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, unsigned int flags) { } static inline int uprobe_mmap(struct vm_area_struct *vma) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 0b7574a54093..1f4151c518ed 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1145,7 +1145,7 @@ __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc) * @offset: offset from the start of the file. * @uc: identify which probe if multiple probes are colocated. */ -void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) +void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, unsigned int flags) { scoped_guard (srcu, &uprobe_srcu) { struct uprobe *uprobe = find_uprobe(inode, offset); @@ -1157,7 +1157,8 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume mutex_unlock(&uprobe->register_mutex); } - synchronize_srcu(&uprobe_srcu); // XXX amortize / batch + if (!(flags & URF_NO_SYNC)) + synchronize_srcu(&uprobe_srcu); } EXPORT_SYMBOL_GPL(uprobe_unregister); diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d1daeab1bbc1..950b5241244a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3182,7 +3182,7 @@ static void bpf_uprobe_unregister(struct path *path, struct bpf_uprobe *uprobes, for (i = 0; i < cnt; i++) { uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset, - &uprobes[i].consumer); + &uprobes[i].consumer, i != cnt-1 ? URF_NO_SYNC : 0); } } diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index c98e3b3386ba..4aafb4485be7 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1112,7 +1112,8 @@ static void __probe_event_disable(struct trace_probe *tp) if (!tu->inode) continue; - uprobe_unregister(tu->inode, tu->offset, &tu->consumer); + uprobe_unregister(tu->inode, tu->offset, &tu->consumer, + list_is_last(trace_probe_probe_list(tp), &tu->tp.list) ? 0 : URF_NO_SYNC); tu->inode = NULL; } }