From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f42.google.com (mail-wr1-f42.google.com [209.85.221.42]) (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 16AB71B3920 for ; Fri, 25 Oct 2024 06:57:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729839457; cv=none; b=D14i/fgwFezhPbiOSNPiEhkv7UP8EW3HV1bMt1Gb7X3i3TqM4kqKNoCBUJY03NPwqWPjlcd6cKpPX81/C+TjbRLPq1PcjGVVuHkX14dPVnPvaan64Z/9v5pN69z10RP5RF5rd7/ki/6ur8/RrVRR2Xkd3x/ll4TdQJxcX9a4z0U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729839457; c=relaxed/simple; bh=N3hO6RuGLcGpKz2OO7Qi0i9vgG5nLurEUPBaxGqGmX4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mXyeiQ+n9RPYqoKYl72eunbP1LCOuEjKmWTHe2q4KcG8dR43+JPl6LWXRqQxwx1kpVHtIshNUER/FikVmpkgs21uxQtZos/ax+nGOOlmzXHttQwfy3AU/wIaLGfnegGReqyRn8JRa8sMeqGHfU0M0v+4S1mhfmacdpBxoCrotTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=JttTjBEn; arc=none smtp.client-ip=209.85.221.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="JttTjBEn" Received: by mail-wr1-f42.google.com with SMTP id ffacd0b85a97d-37d4a5ecc44so1130749f8f.2 for ; Thu, 24 Oct 2024 23:57:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1729839452; x=1730444252; 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=uIGhUUrvEJvBYTpVTQCf7vDRTHIN44D2R4RlMBTCdG4=; b=JttTjBEnJc3j3mu5taK/E9ajpFN6lV/QSLhJLn7Ewr54rubjMg0hF5hFHPo0BZcDIg QbiUc4gL0p4RX3NtsrahOd+A4wS9haGpdtfwrEhtVlp0bWGr7myv7pHa70z5T4wStZ5f kSHJlXabymblrxf0vtKJH7zVzYAehw+TdlsDb8wSEEboybBHLa4gVRP9mmFRRU3pGRWd BFKpglqBVAfCA62OvvuNaQnw90ywRGNQ1MTZ3nHx6w4+Fb6774KCgH97lEB4xSy4lWOd OtNZ6bAiNkoWTH0SiBJ7KXAYYGAYS25Lmeq771TgIUucmLgCsOo4kiAnC6tK83UWSn9n fsGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729839452; x=1730444252; 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=uIGhUUrvEJvBYTpVTQCf7vDRTHIN44D2R4RlMBTCdG4=; b=WHGLa71egjeYGIbqSYZ9rNYJC+yINzgzopjoWZWiliplPiFTVxbOp555ZJpwK1VsAs qHkm/EqM3XBriHxEf/O8LSSxVUkZo65n+AMG4GrYnS0Db/9uysh64f1Ki2E0TVBul0Lv eLh+HK70ljElDV56DbUpDGQixBw0CV4LZh1xbn2XPt5yorrkI2s13uPPyTvQ0zgzkNKO i7bRJp5KhgnhE9KhKkzmi4CwpVUjCPRi5HbI2xeY3xrTmozHu6lmARiukU7ihtJEzQt7 oMGrIrjuN3ckkcnBsGWpNSChc/w2XgV/7FvKwnH/npjsKGiig0B9///3gyZIBF8KJxxX flHg== X-Forwarded-Encrypted: i=1; AJvYcCUrbaiVXBmnj4htEmQs9iywJyRYmtFSv8ijQdFt7230uW+oOw0La1miLDyodnyG89Lm5lIy+SREjXY=@vger.kernel.org X-Gm-Message-State: AOJu0YxwYkRvqePxUlacQPDE/iXjg0cH8T+iUdSPfwvxmpemMHlZEy4s t2zQ1PQQ/IvdzfyW/kXa2w9RTzYgkUNyWRH4+dl6hkVuT3zpv6tmO0Stiw7WiinNcgZhX7jZ8i6 w X-Google-Smtp-Source: AGHT+IG5jRpCojmvKmj5tkta0HqMtVq7AqWJFDLy+BIjGm7NrH0ck5YQqqlaOo1BUh5vNwWV8SPF5w== X-Received: by 2002:adf:e808:0:b0:37d:4ebe:164b with SMTP id ffacd0b85a97d-380458ec1camr2763416f8f.44.1729839452483; Thu, 24 Oct 2024 23:57:32 -0700 (PDT) Received: from localhost (109-81-81-105.rct.o2.cz. [109.81.81.105]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38058b70f25sm749911f8f.67.2024.10.24.23.57.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Oct 2024 23:57:32 -0700 (PDT) Date: Fri, 25 Oct 2024 08:57:31 +0200 From: Michal Hocko To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Roman Gushchin , Muchun Song , Hugh Dickins , Yosry Ahmed , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, Meta kernel team Subject: Re: [PATCH v1 4/6] memcg-v1: no need for memcg locking for writeback tracking Message-ID: References: <20241025012304.2473312-1-shakeel.butt@linux.dev> <20241025012304.2473312-5-shakeel.butt@linux.dev> Precedence: bulk X-Mailing-List: linux-doc@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: <20241025012304.2473312-5-shakeel.butt@linux.dev> On Thu 24-10-24 18:23:01, Shakeel Butt wrote: > During the era of memcg charge migration, the kernel has to be make sure > that the writeback stat updates do not race with the charge migration. > Otherwise it might update the writeback stats of the wrong memcg. Now > with the memcg charge migration deprecated, there is no more race for s@deprecated@gone > writeback stat updates and the previous locking can be removed. > > Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Thanks! > --- > mm/page-writeback.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index a76a73529fd9..9c3317c3a615 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -3083,7 +3083,6 @@ bool __folio_end_writeback(struct folio *folio) > struct address_space *mapping = folio_mapping(folio); > bool ret; > > - folio_memcg_lock(folio); > if (mapping && mapping_use_writeback_tags(mapping)) { > struct inode *inode = mapping->host; > struct backing_dev_info *bdi = inode_to_bdi(inode); > @@ -3114,7 +3113,6 @@ bool __folio_end_writeback(struct folio *folio) > lruvec_stat_mod_folio(folio, NR_WRITEBACK, -nr); > zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr); > node_stat_mod_folio(folio, NR_WRITTEN, nr); > - folio_memcg_unlock(folio); > > return ret; > } > @@ -3127,7 +3125,6 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) > > VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); > > - folio_memcg_lock(folio); > if (mapping && mapping_use_writeback_tags(mapping)) { > XA_STATE(xas, &mapping->i_pages, folio_index(folio)); > struct inode *inode = mapping->host; > @@ -3168,7 +3165,6 @@ void __folio_start_writeback(struct folio *folio, bool keep_write) > > lruvec_stat_mod_folio(folio, NR_WRITEBACK, nr); > zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, nr); > - folio_memcg_unlock(folio); > > access_ret = arch_make_folio_accessible(folio); > /* > -- > 2.43.5 -- Michal Hocko SUSE Labs