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 ECDD9317143; Mon, 2 Mar 2026 17:37:30 +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=1772473053; cv=none; b=Qs2H2Fv4NH/Y9/v5SDkd37StWwobsSAbcQ3KOIjA+TmJPLjVGY690uXOBDwXBgTGL3h7Y8BO1gzleTRG8qwF/npYs3Sf96Nd9lAXlkJlaW4VFkK5XBmhCr/gCdKbHaF9MDyaI5QvjmN19s1y18KMD1n3oGDJxyN196rXBQhWKL4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772473053; c=relaxed/simple; bh=HBZU7lDrqfiSFQCOqZP8QIuscOzDLO1xfpjrl0wUxfI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=r1OvITxG9UIA7TOQWN7cM1FYMgR1Ks3KiotPvAyPBjoyNq5itecnz5ukuy0uJ5UBwOgbH9BN70sfapc2NkBmAxBhSCoCG8JxUhZRlADWsUEOnXOi6DXGcdyhoWoJawPeptKvFo/z00rSpIiD3gbeb8zXjDWAZAQJrv1hYGlxHNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=ehTo4NjD; arc=none smtp.client-ip=90.155.50.34 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=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ehTo4NjD" 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=HBZU7lDrqfiSFQCOqZP8QIuscOzDLO1xfpjrl0wUxfI=; b=ehTo4NjDnDbSNIxrlRcltHgLiK ZFXRHXew8As8wOR37BRxXGVN6MNhYqSj036P4OQs0tY6JLOKITQJ88+z8sdEsQcWgwNIbN0fZVtwv 7Ms57LIVncTKXYIGWSVZpxXDRqx//BZsbVounzAl9KGiWVD8c+3+GNEhHQR4jpQ2OJewH48yL2PDS 581FS0SqPSNntr8+8yPPW8Jnk5q0RX852O3bKuvptQu2PuqyInVMRO8pGBOUx//Rjas5xux+u67UY pLqcqTYZlbLIbxuG2Fe5wcgnm/zioxUglEBT+zfUPnQ93XE5/4Vql0lOjI2Rq12DOwfx7kcG60GEe v+klc6kg==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vx7Cu-00000009qOO-0PEU; Mon, 02 Mar 2026 17:37:24 +0000 Date: Mon, 2 Mar 2026 17:37:23 +0000 From: Matthew Wilcox To: Jan Kara Cc: Tal Zussman , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Jens Axboe , Alexander Viro , Christian Brauner , Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH RFC v3 1/2] filemap: defer dropbehind invalidation from IRQ context Message-ID: References: <20260227-blk-dontcache-v3-0-cd309ccd5868@columbia.edu> <20260227-blk-dontcache-v3-1-cd309ccd5868@columbia.edu> Precedence: bulk X-Mailing-List: linux-kernel@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 Mon, Mar 02, 2026 at 10:11:19AM +0100, Jan Kara wrote: > Folio batches are relatively small (31 folios). With 4k folios it is very > easy to overflow the batch with a single IO completion. Large folios will > obviously make this less likely but I'm not sure reasonable working of > dropbehind should be dependent on large folios... Not sure how to best > address this though. We could use larger batches but that would mean using > our own array of folios instead of folio_batch. That's why I think we should allow the bio to be tagged as "finish the bio in workqueue context", https://lore.kernel.org/linux-fsdevel/aaC3LUFa1Jz2ahk3@casper.infradead.org/ Why remove the folios from one data structure, to put them into a different data structure that they don't necessarily fit in, rather than just postpone processing to workqueue context?