From patchwork Wed May 5 15:05:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12240375 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=-18.8 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,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 AB1E8C433ED for ; Wed, 5 May 2021 16:14:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8275460725 for ; Wed, 5 May 2021 16:14:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233875AbhEEQPU (ORCPT ); Wed, 5 May 2021 12:15:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233838AbhEEQPR (ORCPT ); Wed, 5 May 2021 12:15:17 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EF99C061574; Wed, 5 May 2021 09:14:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=c2T2PlaSxh3xoS1T4IYREbul8jvjAA2s9H7C2q83KAw=; b=TCq4FXOEoskSoI96YHXI3agNy6 ooqsELIjpoJsnAlf6MDdir6IUCT40SXvLCD8kdJnlgNdgYrsSs55N+msYGNckTH56MxffJwWYyOId DofbBByqbqH3qtZ0YF8NQAaAA7x26d+leNe9dPKYvwfgclIPeXQh+YIwCNwby0ahOJKuwzggx/UCn j3T1FLtG81pS/W0KXN+TEPDxK7O4jI30b9qE5EhJWbwrUOWXqnX0nBHEQ1slRG1CBoeeCxbQrxBlq EW//OK6LWbGk1aFd1TrhYLGTuu3naMszdA5eMP+GudxkrvQMIFjASUcKpnRAmS5efXNHtZjbEL91K twR7QnjA==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1leK95-000ZWD-GT; Wed, 05 May 2021 16:13:19 +0000 From: "Matthew Wilcox (Oracle)" To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org Subject: [PATCH v9 55/96] flex_proportions: Allow N events instead of 1 Date: Wed, 5 May 2021 16:05:47 +0100 Message-Id: <20210505150628.111735-56-willy@infradead.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210505150628.111735-1-willy@infradead.org> References: <20210505150628.111735-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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) --- 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 157ed52e4b7d..764e92bd9014 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -572,8 +572,8 @@ 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)) { /*