From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7238FC11F66 for ; Tue, 13 Jul 2021 14:39:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E816761154 for ; Tue, 13 Jul 2021 14:39:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E816761154 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2DE2C8D0001; Tue, 13 Jul 2021 10:39:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2B4E56B0096; Tue, 13 Jul 2021 10:39:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 17DEE8D0001; Tue, 13 Jul 2021 10:39:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0179.hostedemail.com [216.40.44.179]) by kanga.kvack.org (Postfix) with ESMTP id E8B0C6B0095 for ; Tue, 13 Jul 2021 10:39:52 -0400 (EDT) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 012D91826FD2C for ; Tue, 13 Jul 2021 14:39:52 +0000 (UTC) X-FDA: 78357823824.04.9464822 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf14.hostedemail.com (Postfix) with ESMTP id 5ED9160019AC for ; Tue, 13 Jul 2021 14:39:51 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id EE114201E5; Tue, 13 Jul 2021 14:39:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1626187189; h=from:from:reply-to: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=zJgth62e6DRwxuE1p4QeibZRXKh6lnd/FGpb00zXtco=; b=O68ObX8MG6BlpUhu/xBv9j7G1mYqUdqLnRyV03xbqEujXuAfy0gpOA9lJ/F4bdBCKke3Lk a/MXrhFnAh+ZWYWAl3kgsN5DvQbJlWQV8LmNxkZMvNL2ViqzuUBDde0tvQuoR/1YT88dFm 1AYwhHBSkTc0TaS/25XfTyoazBgd9JM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1626187189; h=from:from:reply-to: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=zJgth62e6DRwxuE1p4QeibZRXKh6lnd/FGpb00zXtco=; b=8I2ejwrN0kq14Tnws/o7U/fah1Jw9rBREUuBXF5M68+gOMotjQpjh0qFRfO0R5JN5U1NiW veZxhd2s1RXuuSCQ== Received: from quack2.suse.cz (unknown [10.100.224.230]) by relay2.suse.de (Postfix) with ESMTP id E1AB2A3B85; Tue, 13 Jul 2021 14:39:49 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id BE9F11E0BBE; Tue, 13 Jul 2021 16:39:49 +0200 (CEST) Date: Tue, 13 Jul 2021 16:39:49 +0200 From: Jan Kara To: "Matthew Wilcox (Oracle)" Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig Subject: Re: [PATCH v13 064/137] flex_proportions: Allow N events instead of 1 Message-ID: <20210713143949.GB24271@quack2.suse.cz> References: <20210712030701.4000097-1-willy@infradead.org> <20210712030701.4000097-65-willy@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210712030701.4000097-65-willy@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=O68ObX8M; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=8I2ejwrN; spf=pass (imf14.hostedemail.com: domain of jack@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=jack@suse.cz; dmarc=none X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 5ED9160019AC X-Stat-Signature: i1b47gbyw83fjjijorisf75cer7hkmw9 X-HE-Tag: 1626187191-950743 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: On Mon 12-07-21 04:05:48, Matthew Wilcox (Oracle) wrote: > When batching events (such as writing back N pages in a single I/O), it > is better to do one flex_proportion operation instead of N. There is > only one caller of __fprop_inc_percpu_max(), and it's the one we're > going to change in the next patch, so rename it instead of adding a > compatibility wrapper. > > Signed-off-by: Matthew Wilcox (Oracle) > Reviewed-by: Christoph Hellwig Looks good. You can add: Reviewed-by: Jan Kara Honza > --- > include/linux/flex_proportions.h | 9 +++++---- > lib/flex_proportions.c | 28 +++++++++++++++++++--------- > mm/page-writeback.c | 4 ++-- > 3 files changed, 26 insertions(+), 15 deletions(-) > > diff --git a/include/linux/flex_proportions.h b/include/linux/flex_proportions.h > index c12df59d3f5f..3e378b1fb0bc 100644 > --- a/include/linux/flex_proportions.h > +++ b/include/linux/flex_proportions.h > @@ -83,9 +83,10 @@ struct fprop_local_percpu { > > int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp); > void fprop_local_destroy_percpu(struct fprop_local_percpu *pl); > -void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl); > -void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl, > - int max_frac); > +void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl, > + long nr); > +void __fprop_add_percpu_max(struct fprop_global *p, > + struct fprop_local_percpu *pl, int max_frac, long nr); > void fprop_fraction_percpu(struct fprop_global *p, > struct fprop_local_percpu *pl, unsigned long *numerator, > unsigned long *denominator); > @@ -96,7 +97,7 @@ void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl) > unsigned long flags; > > local_irq_save(flags); > - __fprop_inc_percpu(p, pl); > + __fprop_add_percpu(p, pl, 1); > local_irq_restore(flags); > } > > diff --git a/lib/flex_proportions.c b/lib/flex_proportions.c > index 451543937524..53e7eb1dd76c 100644 > --- a/lib/flex_proportions.c > +++ b/lib/flex_proportions.c > @@ -217,11 +217,12 @@ static void fprop_reflect_period_percpu(struct fprop_global *p, > } > > /* Event of type pl happened */ > -void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl) > +void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl, > + long nr) > { > fprop_reflect_period_percpu(p, pl); > - percpu_counter_add_batch(&pl->events, 1, PROP_BATCH); > - percpu_counter_add(&p->events, 1); > + percpu_counter_add_batch(&pl->events, nr, PROP_BATCH); > + percpu_counter_add(&p->events, nr); > } > > void fprop_fraction_percpu(struct fprop_global *p, > @@ -253,20 +254,29 @@ void fprop_fraction_percpu(struct fprop_global *p, > } > > /* > - * Like __fprop_inc_percpu() except that event is counted only if the given > + * Like __fprop_add_percpu() except that event is counted only if the given > * type has fraction smaller than @max_frac/FPROP_FRAC_BASE > */ > -void __fprop_inc_percpu_max(struct fprop_global *p, > - struct fprop_local_percpu *pl, int max_frac) > +void __fprop_add_percpu_max(struct fprop_global *p, > + struct fprop_local_percpu *pl, int max_frac, long nr) > { > if (unlikely(max_frac < FPROP_FRAC_BASE)) { > unsigned long numerator, denominator; > + s64 tmp; > > fprop_fraction_percpu(p, pl, &numerator, &denominator); > - if (numerator > > - (((u64)denominator) * max_frac) >> FPROP_FRAC_SHIFT) > + /* Adding 'nr' to fraction exceeds max_frac/FPROP_FRAC_BASE? */ > + tmp = (u64)denominator * max_frac - > + ((u64)numerator << FPROP_FRAC_SHIFT); > + if (tmp < 0) { > + /* Maximum fraction already exceeded? */ > return; > + } else if (tmp < nr * (FPROP_FRAC_BASE - max_frac)) { > + /* Add just enough for the fraction to saturate */ > + nr = div_u64(tmp + FPROP_FRAC_BASE - max_frac - 1, > + FPROP_FRAC_BASE - max_frac); > + } > } > > - __fprop_inc_percpu(p, pl); > + __fprop_add_percpu(p, pl, nr); > } > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index e677e79c7b9b..63c0dd9f8bf7 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -566,8 +566,8 @@ static void wb_domain_writeout_inc(struct wb_domain *dom, > struct fprop_local_percpu *completions, > unsigned int max_prop_frac) > { > - __fprop_inc_percpu_max(&dom->completions, completions, > - max_prop_frac); > + __fprop_add_percpu_max(&dom->completions, completions, > + max_prop_frac, 1); > /* First event after period switching was turned off? */ > if (unlikely(!dom->period_time)) { > /* > -- > 2.30.2 > -- Jan Kara SUSE Labs, CR