From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31D5420C026 for ; Wed, 11 Dec 2024 03:43:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733888634; cv=none; b=blmoqmcllN90FUbOsJ57mMeDcxqJS5JsJL7ZV4mcZGIoX3uO+CguRHjRD+FzLf71me/hmruzJCgGDcZqma6SbAR0Sc12WAVNLVOWNlUGZqWHQmcb19eUdglLF4JBIjx3JwbEISdE6BndnkZcbKUSfZyc8hpkPhaC78qgvw2TQgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733888634; c=relaxed/simple; bh=3qmb6n2k5jyQxy/EaKqykA7/FzwxzB6BLnxQE1aCQSM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EVY2CjXgY8EClD2kGa4jKjOmyJ9SKROvoewpuayEfuRNOGuNvfYta9Q+K4fswiZWwEefgyzYrJX18WCm7x6lTxqyU2DswYzWOB6CPffdUSc7ouZeztL9eBxja4QkPiKPUIDbEBjqf7zDSD9wOZ7j9Wasd9sQU4E/IN71+VpsKd0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=nGJg517l; arc=none smtp.client-ip=209.85.214.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="nGJg517l" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-2165cb60719so21953095ad.0 for ; Tue, 10 Dec 2024 19:43:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1733888632; x=1734493432; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=/Ay9jjGFrKSAl3bI/vTKsN5E9jw7DK63y+NCGY7vvAw=; b=nGJg517l6V4UWgTEodc72v8VfS3oS/FjYTWt2aVCEIGe8HGcMUTpha8hBw4I0oDTa0 DwajsHuF9qquFnp+MMRmVxPfbm1mWmFRIeMyGyDq81oYYrjvtQxm8XfkPj/VjVjag0T+ USr0sLv74EC/S3kd3dlaiLqT6nJnQC7S4VL9c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733888632; x=1734493432; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/Ay9jjGFrKSAl3bI/vTKsN5E9jw7DK63y+NCGY7vvAw=; b=MfviVkl5+vG/DimOI6X5I1eXurLTMdGn5FKeLEMk6QCayZPRsInPIy0QHRyNK0lcmG W/y8Gblq8XtWZCrNzqow0UlZUMmekILE16/aqsu/sdQ2qjaTPY5k3/FaUG+b7BA1Xv8m h7HmpSg6uf3ZfXgjVLvDAoAfbUdNh+cJD9TVQ5KnnLDvvs3hqCBKTHrEmXyfAf9lMu8Z +NRntxIdCJ0D5ZQeHAj0W5dwLrs3+2Qtwn/gL2TW/Pc6lF+2O7ZKrwbL2uvv5OwFnFzx eVQyx6xftyR/Rh5Bc0jBykyIYXYHNxvHvEjogat1uHOFUUz//wb81bM9A0b0RmBPOvWt cqnA== X-Forwarded-Encrypted: i=1; AJvYcCXpM7irJSI7/kuUzO4KeFEdKR4Rp8U9B270Y1k8m3WPL9+BcTeR0zDv0Tk0sGE4xIHRXVX9SpS+1F8WWGw=@vger.kernel.org X-Gm-Message-State: AOJu0YwtwByyEXdrH9PlxSRw65ON7WkSO33+ri7RyVFjE7B002h5CD7/ M+S53m7w8nlzlwmRTV21jCTNvXYxqou+shtwHUn0dZzAwitt3Uvy/FBYTxmCR63HWLBZd1mH7a4 = X-Gm-Gg: ASbGnctR+opkhz+hEV/PVdsE1vteXIa80JxXb9QIL61Z5N29PHC7c37oLcuTKoovzBs G5Om5AjptmkTSc47+l7H0GlBPSHpK1VIOdTK1gv76SOZdEhPx8XmLnnq3auTXrijogdfG2YAv7w 7bBCURoU/ZUT8PU5HGjtSnrRc8X87W/PZn+one3adbot/TCxmWhSstW2cKZFKGXzdAKquh3td1N 1abHzdQIgisgqOlkrxSfFFwczItVh8vn7MM4qRv32Y7Bm0P5ioa8cby3A== X-Google-Smtp-Source: AGHT+IG7fmSiS1eRU5dgXKaz1kWycM3+vaUeoUL62BZ1R6/arQU36zJoWoargKVw37KjdCddDfFz3Q== X-Received: by 2002:a17:902:f60e:b0:216:2bd7:1c49 with SMTP id d9443c01a7336-21778535677mr27648725ad.29.1733888632547; Tue, 10 Dec 2024 19:43:52 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:4d97:9dbf:1a3d:bc59]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-215f8f26c6csm97547695ad.233.2024.12.10.19.43.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Dec 2024 19:43:52 -0800 (PST) Date: Wed, 11 Dec 2024 12:43:48 +0900 From: Sergey Senozhatsky To: Andrew Morton Cc: Sergey Senozhatsky , Minchan Kim , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/6] zram: cond_resched() in writeback loop Message-ID: <20241211034348.GA2091455@google.com> References: <20241210105420.1888790-1-senozhatsky@chromium.org> <20241210105420.1888790-2-senozhatsky@chromium.org> <20241210165456.288ed82b8a66a08ac36a4d15@linux-foundation.org> 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: <20241210165456.288ed82b8a66a08ac36a4d15@linux-foundation.org> On (24/12/10 16:54), Andrew Morton wrote: > > Writeback loop can run for quite a while (depending on > > wb device performance, compression algorithm and the > > number of entries we writeback), so we need to do > > cond_resched() there, similarly to what we do in > > recompress loop. > > > > ... > > > > --- a/drivers/block/zram/zram_drv.c > > +++ b/drivers/block/zram/zram_drv.c > > @@ -889,6 +889,8 @@ static ssize_t writeback_store(struct device *dev, > > next: > > zram_slot_unlock(zram, index); > > release_pp_slot(zram, pps); > > + > > + cond_resched(); > > } > > > > if (blk_idx) > > Should this be treated as a hotfix? With a -stable backport? > > If so, we'd need to explain our reasoning in the changelog. "Fixes a > watchdog lockup splat when running ". And a Fixes: would be > nice if appropriate. Good point. This fixes commit from 2018, I guess no one runs writebacks on preempt-none systems, but I don't see why this should be in -stable. I'll send updated patch in a bit.