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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1736952485; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rbMytknc3TiRLkmbEfTXok3cGmZUKWcYKEuelb56Dt0=; b=hlGwI8o0aZc0bYVYcSlYNhU5RHE5zIj/Nap2XusjRoWiyJ7807swoz8W5kGuGkx3Bk8I0w 43ON+1lUnN4agcp+t245T7T/5vT1LVTzxcJhYWXWmL//eCcuB29pATRhUiLsGQGgIWe7Fa 9AP6FGGuBc/thteyhl6YEi+KO5WcrSM= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=manguebit.com; s=dkim; t=1736952482; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rbMytknc3TiRLkmbEfTXok3cGmZUKWcYKEuelb56Dt0=; b=SfdfFSXkrhveSJn4zx9uJx1EkyGBCUYeCsZuRoKnSRel4TT1PocIdDtsBInvJd6O4gzgMr B1M+nTAyy8QlAgQEHPSUR3szQhrmIL5aCd7r6oDkV1RAIECrC8iTseKfxkhzAIr3ZqtoMM UPvEwTVrko/hGqyNR2Q27pyZg31wHCuunSl3S9yCfdi5oWaqtlLJCFK0nzn0kTNmYl4nSe 6O0ed8V+wXOKIG+oEnqIM32Kt7qNXNAqW5HT0WmnPOgaoUNtrrY35utUVx6evTz1ZQ6heX n8RLAYtgaQd2e5Pt10kCl2JNx9loesn0SL60MJUjwwTex0uyV1A2M5vmEDQfwQ== From: Paulo Alcantara To: Shyam Prasad N Cc: Benjamin Coddington , Amir Goldstein , lsf-pc@lists.linux-foundation.org, linux-fsdevel , linux-mm@kvack.org, brauner@kernel.org, Matthew Wilcox , David Howells , Jeff Layton , Steve French , trondmy@kernel.org, Shyam Prasad N Subject: Re: [LSF/MM/BPF TOPIC] Predictive readahead of dentries In-Reply-To: References: <460E352E-DDFA-4259-A017-CAE51C78EDFC@redhat.com> Date: Wed, 15 Jan 2025 11:47:58 -0300 MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 984F9140002 X-Stat-Signature: 7fef5jpicut9rttd91tb1fqrs1rr8o7n X-Rspam-User: X-HE-Tag: 1736952484-30326 X-HE-Meta: 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 S4eV2lkK RaIq7T+ivlHzgIkhc306QgP/1J33ejI+I6may4895XjZxWZJxje9O2HBPsv3yrlWxRxDbyxXl7IgPV3GxC7Htppidpp86xzPT7uPGUiPJe2Y4k5yJrcoOr7yiGC409e7YXT2K X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Shyam Prasad N writes: > We load the dentry cache with results of QueryDirectory. But what I'm > proposing here is a read ahead, even before the next readdir is done > by the application. i.e. the idea is that the data necessary to emit > dentries is already in the cache before it is even called. That should > speed up the overall directory reads. Thanks for the explanation. We'd need to be careful as in CIFS we could end up with several automounts (DFS links) by doing these readdirs in advance, especially on slow connections and when failover happens when mounting them.