From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 C7C2F346AC7; Wed, 17 Dec 2025 09:53:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765965194; cv=none; b=hXJGQRP8ubqrC5Dy2g8pQ6iSQX+nsxW/+ckLI2j+Z6ynqytZRC9sUn/huljbaPbuAwiLuTm5YPZv9hbuKaom+ZoEklelVysfx99zm26tUCQ26mUuVAx45LWlfDsYPWCUNoURlfQmvGdDLETsfQZTykk6+Y6OEVw8Uv3JWRB2bQc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765965194; c=relaxed/simple; bh=t0dt5W7LqrxVgiMOA0wHVeB3WrzIJmfYJueL0ZOkYkY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FSA/WrYgbsPJLUuXH61OKLlbWXXeve9CbLqh4f2CB5WLbO2i8wMvxHCOefV07W3LJOG2EacTvRRLcDhtAUlJ16GL340Iv+2TS1GMuYsNiNNw73JCRGt07jGrVa73UimA4Mj1uTwFKIwtvO+z4fARj3LgHbNBgx/BcUrH8UBnuns= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=mePx01jH; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mePx01jH" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=PO1jsG4jXKSEd/L3L2y2/CD52Pekw8rFFMDDN18aPKo=; b=mePx01jHapQQt6AS2cZZ8c0CCt RYp1EBnErtuDtsgIgfP8N1/kOQV9j6gXZq8KTMVALZ5nauifczdffHYxegciU/hXraL4IOYHXP+uf 03wwRGw11TgZfemYerIZLLic3u8lY/YVTQRVJRAFy/Q87WbmBIXTKvwoN02ZzzduppR7V7r+MFwuh yrIDGgcMPrxVzQmwhsWyfSsxrxfsD0FlI3N+CpZUL9xjkqPweRZEM1N+r6lelxAI56lQGt++xIXMl aR1lfxlA2S8d9X2YJSllstoTiIbppnBij5ZS1ROZWtxjQ8YK+CXGJ4eCXmmeIvW8QN4xlYOe28kTA vgm6FBKw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vVoDW-00000006Tdd-40Yg; Wed, 17 Dec 2025 09:53:10 +0000 Date: Wed, 17 Dec 2025 01:53:10 -0800 From: Christoph Hellwig To: Trond Myklebust Cc: Linus Torvalds , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Viro , Christian Brauner , linux-fsdevel@vger.kernel.org, Anna Schumaker Subject: Re: NFS dentry caching regression? was Re: [GIT PULL] Please pull NFS client updates for Linux 6.19 Message-ID: References: <36d449e22bf28df97c7717ab4dfb30f100f159a4.camel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Dec 17, 2025 at 01:32:30AM -0800, Christoph Hellwig wrote: > Hi all, > > the merge of this branch causes NFS lookup operation to shoot up a lot > for me. And with merge I mean merge - both parent of the merge on their > own are fine. > > With the script below that simulates running python scripts with lots > of imports that was created to benchmark delegation performance, the > number of lookups in the measurement period shoots up from 4 to about > 410000, which is a bit suboptimal. I have no idea how this could > happen, but it must be related to some sort of pathname lookup changes > I guess. Other operations looks roughly the same. To further pin this down, I rebased the patches from the NFS pull request on top of the baseline (d358e5254674b70f34c847715ca509e46eb81e6f) and bisected that. This ends up in: NFS: Shortcut lookup revalidations if we have a directory delegation