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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C4FFC433EF for ; Thu, 6 Jan 2022 18:14:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242592AbiAFSOY (ORCPT ); Thu, 6 Jan 2022 13:14:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242600AbiAFSOV (ORCPT ); Thu, 6 Jan 2022 13:14:21 -0500 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01D72C061245 for ; Thu, 6 Jan 2022 10:14:21 -0800 (PST) Received: by mail-pj1-x1034.google.com with SMTP id gp5so3170230pjb.0 for ; Thu, 06 Jan 2022 10:14:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=GoH2UN/8qkqabVyCewCEHBZi5Bqh3qhRr5ggOkTJFF4=; b=aQxvqSJhcL4KnFJO2E6onDSXG/6X25osguzKHpo2otgIlcDIu7jxz8hG4q7woDNfc3 ohTukTjB82nmeIRDqvrrOTmeaa0mILoVUemZ8wK/FjPJ1pzXBej44p5GNDLJQwVjc4Bb 2lYlh5Q4lIkvYynjiPb48LG7zS0HTbAyJb038jyJQC64PI4PiaWzNxpFRD/nIJxCN1ST So8uX/VfsET5sQymJzbQ6gki1PDxvdfLl5ltlriMOe+C1LfsSSl7t3C4vXTOVGPo3EOy NEb6djaIB22chEKBFUQUoE6AoYRGwXLeaR1T41NzfdDr9xa3XNGYktwSuCzUKHNyomrZ 7n9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=GoH2UN/8qkqabVyCewCEHBZi5Bqh3qhRr5ggOkTJFF4=; b=OFSMP9KmNCrC7h+DRVeWykM2fd3HnkROpPmzLlg6XpbWppflKhbxpVVkg/+/pUHkHx BTydo8nkFU6i6uqFLGqhsdQTHjHKEg9isomLIJoCeR5+ixw8XKiZ41UKKpCfvHlC/+Eu sVeAfRMK0gww3EdhArBPJ0x2GHzlEulIXgJSZjVB5IP5M5iFU6slgsfmEAORjfhd8REU DKLsblFa5BjQLWpRYH1DbakSE5c+AN82eTgnKA6ljAyFzm1cGld6oYz4xd3vXNGD4SYS DGlvpnMwUsewMNqj3+L+tcmzj7zQpNngbrrwtOGFpP5wEytdjBL+GxBFNguzhRynjrnv iJhA== X-Gm-Message-State: AOAM532gkPWv07EpWKcbLfezfF3NRGDk8qU2zTQEbcJEHcM+c3dREOiv f2HiMwDJnHb+wcPMpesR9qsXB8go+Pc= X-Google-Smtp-Source: ABdhPJzWO9L/JV+JRJxU8f2mZoQwRPPTOlhPOIY/mp+2/vFRiWi5b7QYr/uMrLmIH8AlJDVCRRpWtw== X-Received: by 2002:a17:90b:688:: with SMTP id m8mr5421498pjz.62.1641492860292; Thu, 06 Jan 2022 10:14:20 -0800 (PST) Received: from google.com ([2620:15c:211:201:e32:b92d:27fe:aa55]) by smtp.gmail.com with ESMTPSA id mw8sm2992238pjb.42.2022.01.06.10.14.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jan 2022 10:14:19 -0800 (PST) Sender: Minchan Kim Date: Thu, 6 Jan 2022 10:14:17 -0800 From: Minchan Kim To: Andrew Morton Cc: Michal Hocko , David Hildenbrand , linux-mm , LKML , Suren Baghdasaryan , John Dias Subject: Re: [RESEND][PATCH v2] mm: don't call lru draining in the nested lru_cache_disable Message-ID: References: <20211230193627.495145-1-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211230193627.495145-1-minchan@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 30, 2021 at 11:36:27AM -0800, Minchan Kim wrote: > lru_cache_disable involves IPIs to drain pagevec of each core, > which sometimes takes quite long time to complete depending > on cpu's business, which makes allocation too slow up to > sveral hundredth milliseconds. Furthermore, the repeated draining > in the alloc_contig_range makes thing worse considering caller > of alloc_contig_range usually tries multiple times in the loop. > > This patch makes the lru_cache_disable aware of the fact the > pagevec was already disabled. With that, user of alloc_contig_range > can disable the lru cache in advance in their context during the > repeated trial so they can avoid the multiple costly draining > in cma allocation. Hi Folks, Any comment to proceed the work? > > Signed-off-by: Minchan Kim > --- > * from v1 - https://lore.kernel.org/lkml/20211206221006.946661-1-minchan@kernel.org/ > * fix lru_cache_disable race - akpm > > include/linux/swap.h | 14 ++------------ > mm/cma.c | 5 +++++ > mm/swap.c | 30 ++++++++++++++++++++++++++++-- > 3 files changed, 35 insertions(+), 14 deletions(-) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index ba52f3a3478e..fe18e86a4f13 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -348,19 +348,9 @@ extern void lru_note_cost_page(struct page *); > extern void lru_cache_add(struct page *); > extern void mark_page_accessed(struct page *); > > -extern atomic_t lru_disable_count; > - > -static inline bool lru_cache_disabled(void) > -{ > - return atomic_read(&lru_disable_count); > -} > - > -static inline void lru_cache_enable(void) > -{ > - atomic_dec(&lru_disable_count); > -} > - > +extern bool lru_cache_disabled(void); > extern void lru_cache_disable(void); > +extern void lru_cache_enable(void); > extern void lru_add_drain(void); > extern void lru_add_drain_cpu(int cpu); > extern void lru_add_drain_cpu_zone(struct zone *zone); > diff --git a/mm/cma.c b/mm/cma.c > index 995e15480937..60be555c5b95 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -30,6 +30,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -453,6 +454,8 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, > if (bitmap_count > bitmap_maxno) > goto out; > > + lru_cache_disable(); > + > for (;;) { > spin_lock_irq(&cma->lock); > bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, > @@ -492,6 +495,8 @@ struct page *cma_alloc(struct cma *cma, unsigned long count, > start = bitmap_no + mask + 1; > } > > + lru_cache_enable(); > + > trace_cma_alloc_finish(cma->name, pfn, page, count, align); > > /* > diff --git a/mm/swap.c b/mm/swap.c > index af3cad4e5378..5f89d7c9a54e 100644 > --- a/mm/swap.c > +++ b/mm/swap.c > @@ -847,7 +847,17 @@ void lru_add_drain_all(void) > } > #endif /* CONFIG_SMP */ > > -atomic_t lru_disable_count = ATOMIC_INIT(0); > +static atomic_t lru_disable_count = ATOMIC_INIT(0); > + > +bool lru_cache_disabled(void) > +{ > + return atomic_read(&lru_disable_count) != 0; > +} > + > +void lru_cache_enable(void) > +{ > + atomic_dec(&lru_disable_count); > +} > > /* > * lru_cache_disable() needs to be called before we start compiling > @@ -859,7 +869,21 @@ atomic_t lru_disable_count = ATOMIC_INIT(0); > */ > void lru_cache_disable(void) > { > - atomic_inc(&lru_disable_count); > + static DEFINE_MUTEX(lock); > + > + /* > + * The lock gaurantees lru_cache is drained when the function > + * returned. > + */ > + mutex_lock(&lock); > + /* > + * If someone is already disabled lru_cache, just return with > + * increasing the lru_disable_count. > + */ > + if (atomic_inc_not_zero(&lru_disable_count)) { > + mutex_unlock(&lock); > + return; > + } > #ifdef CONFIG_SMP > /* > * lru_add_drain_all in the force mode will schedule draining on > @@ -873,6 +897,8 @@ void lru_cache_disable(void) > #else > lru_add_and_bh_lrus_drain(); > #endif > + atomic_inc(&lru_disable_count); > + mutex_unlock(&lock); > } > > /** > -- > 2.34.1.448.ga2b2bfdf31-goog >