From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 63CD6133417; Thu, 15 Feb 2024 15:37:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708011468; cv=none; b=Kvnyl7+WOhRaIAQUR2Ip05KVYhBibN9ScMKUD9JkI7WIMusXXnFe4PMGcOXEMBTW4PfrqBQ5Y3qm1NcBcAHrwVy8cXh1AQy60oNyDQ7lizPgBcwK77u3YeH1MS7HDN5lGBUvHNPL71yPScsYRjSzE4sbAjPjsOdK0jil3xUsJKk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708011468; c=relaxed/simple; bh=epnqDWcnhsCvgG8kTNd2ESNKS8KdAlToJJsau8BMXIc=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=fqd7swddS0Lf7lOsvRQauWLqkCngJsv+xOfXzbCgvFHkqdAk+Lf5lYpHzrjxhmC0M9oGVB26o2zAuWh0ik/Rf/U9HBQRidgp5L+ysdSsfECUGYp59ubxihxd8fI1wHqT5PEpSVeQsaPtCH3yNF8xjtKxJQb4J/t0hLNlM7C4HMw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fnRNpVvc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fnRNpVvc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8EA5C433F1; Thu, 15 Feb 2024 15:37:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708011467; bh=epnqDWcnhsCvgG8kTNd2ESNKS8KdAlToJJsau8BMXIc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fnRNpVvcgGMxdGApcy7TF29tirSa8C8+JxMTmSMPju7g0ZJMbUtGqichvYZSP+Cvy 1UH+zm1VYtXWmZZCvRHHCVY6ThHOj9dYo5g5wrQlVV82SfTl/uN1iCQuDsV1B6gp96 AaxASn+DTHmY5GpcHLPBZh8yYNrbY/ExsiDEte20tS2y2HBGiZzycjx5ynhNtNjtxB abStxkeTu28p/IN886ODSYyYVYcojM592btmkZHl60Ivou0y71N1TJlqfhU8lWaP9N Cy8xkYpxZQqqnKpUcWwdmsMt0GGz2J/kiNioZSSyJhypqNSEy6V8/YkmshLMV/YJlR 6qlD14QTLTErw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1rado1-003YAI-Iw; Thu, 15 Feb 2024 15:37:45 +0000 Date: Thu, 15 Feb 2024 15:37:45 +0000 Message-ID: <86jzn54u2e.wl-maz@kernel.org> From: Marc Zyngier To: Oliver Upton Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, James Morse , Suzuki K Poulose , Zenghui Yu , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 00/23] KVM: arm64: Improvements to LPI injection In-Reply-To: References: <20240213093250.3960069-1-oliver.upton@linux.dev> <86y1bn3pse.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: oliver.upton@linux.dev, kvmarm@lists.linux.dev, kvm@vger.kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Wed, 14 Feb 2024 18:40:27 +0000, Oliver Upton wrote: > > On Wed, Feb 14, 2024 at 05:43:13PM +0000, Marc Zyngier wrote: > > On Tue, 13 Feb 2024 09:32:37 +0000, > > Oliver Upton wrote: > > > > > > For full details on the what/why, please see the cover letter in v1. > > > > > > Apologies for the delay on v2, I wanted to spend some time to get a > > > microbenchmark in place to slam the ITS code pretty hard, and based on > > > the results I'm glad I did. > > > > [...] > > > > Buglets and potential improvements aside, I like the smell of this. At > > least the first handful of patches could easily be taken as a separate > > improvement series. > > > > Let me know how you'd like to play this. > > Yeah, I think there's 3 independent series here if we want to take the > initial improvements: > > - Address contention around vgic_get_irq() / vgic_put_irq() with the > first 10 patches. Appears there is violent agreement these are good > to go. > > - Changing out the translation cache into a per-ITS xarray > > - A final series cleaning up a lot of the warts we have in LPI > management, like vgic_copy_lpi_list(). I believe we can get rid of > the lpi_list_lock as well, but this needs to be ordered after the > first 2. > > I'd really like to de-risk the performance changes from the cleanups, as > I'm convinced they're going to have their own respective piles of bugs. > > How does that sound? Yup, I'd be on board with that. If you can respin the first part with bugs fixed and without the stats, that'd be great. We can further bikeshed on the rest in the 6.10 time frame. Also please Cc: Eric Auger, as he dealt with a lot of the ITS save/restore stuff. Thanks, M. -- Without deviation from the norm, progress is not possible.