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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA89BCCA47E for ; Mon, 20 Jun 2022 08:08:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C2AF6B0073; Mon, 20 Jun 2022 04:08:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 14A516B0074; Mon, 20 Jun 2022 04:08:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F2E556B0075; Mon, 20 Jun 2022 04:08:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id E14256B0073 for ; Mon, 20 Jun 2022 04:08:52 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id B264FAB0 for ; Mon, 20 Jun 2022 08:08:52 +0000 (UTC) X-FDA: 79597888104.23.9E630D6 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf26.hostedemail.com (Postfix) with ESMTP id 1EE5714000B for ; Mon, 20 Jun 2022 08:08:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655712530; x=1687248530; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=LQztEc1EBzzs8KWwqzXaMQMFrLTcUbledaOBZycBMFo=; b=Ku75Z6NQdj6/WfP567WIW7MxCn3g5PRIqFb2/WagypeFxvoViZU4llrc 7tTtmOK2OxVqPoziJhhuForMH12mqEi+TIV1iBlo1es89xVu/L32iB3Yj VPWQLRQD94fSx1RFaeg1FS8FiE023KinT9YfhYLN/LYhWV45MFRlQCaDk R9NpyEcMJ0x62Qj8S7BhfjnWCVR389y+jVuH/M9PRIoNwDiFRb0uSvegb QPDmRLBIbSTx1ppL6Ytlg/zoLRtlKjcLNB8+rFPsH+SdfpQwsEmw5iOox 1VloIYXed8uIYNZVP+wxVnY2knYpI21i9P+8AXntdwbFtjbGPSQGOAodV w==; X-IronPort-AV: E=McAfee;i="6400,9594,10380"; a="280890874" X-IronPort-AV: E=Sophos;i="5.92,306,1650956400"; d="scan'208";a="280890874" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2022 01:08:48 -0700 X-IronPort-AV: E=Sophos;i="5.92,306,1650956400"; d="scan'208";a="833004001" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.239.13.94]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jun 2022 01:08:46 -0700 From: "Huang, Ying" To: Miaohe Lin Cc: , , , Subject: Re: [PATCH v2 3/3] mm/swap: remove swap_cache_info statistics References: <20220608144031.829-1-linmiaohe@huawei.com> <20220608144031.829-4-linmiaohe@huawei.com> Date: Mon, 20 Jun 2022 16:08:42 +0800 In-Reply-To: <20220608144031.829-4-linmiaohe@huawei.com> (Miaohe Lin's message of "Wed, 8 Jun 2022 22:40:31 +0800") Message-ID: <87a6a7rc39.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655712530; a=rsa-sha256; cv=none; b=vVbzGpjH//vDOc4ObdrbAywxfph4IjeXfswwdx9zIg5xggV2O0I6/LeD4eSe0Q0h3+HYuT YivBDbgrMP1co8N2tJZEzLCvwxu+N22aKw8aoNDnjEIumZA6gWpWG4rvjtmVldxcxj6Nog Isoq+4fYzYIv6y0b5UKpQ0dYgfOwUtw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655712530; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Hbm8fSZkkKrua2FqSr08Glb+xuAeDJBc9/S+xuSsCTA=; b=2yw+BxLvpleOMd1yUbuZh8yY+/zO6Ce0riFEHzJXf0Rr+WSH6hwyfAgqxJVG6rs81me2uw eECrEu7YzXhuQKCsGraWPLIXXkTZzdnagVSnUXiAKVgHjpVpQneQDfpy8QeHd0W1jTk5m8 lAx7DmeT/ml6tqyEJwTJsTUzE+BNaCg= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Ku75Z6NQ; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf26.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=ying.huang@intel.com Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=Ku75Z6NQ; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf26.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=ying.huang@intel.com X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 1EE5714000B X-Stat-Signature: 36r1kgpzfh9ckmy7w6sfcf1gqnutudjn X-HE-Tag: 1655712529-233008 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: Miaohe Lin writes: > swap_cache_info are not statistics that could be easily used to tune system > performance because they are not easily accessile. Also they can't provide > really useful info when OOM occurs. Remove these statistics can also help > mitigate unneeded global swap_cache_info cacheline contention. > > Suggested-by: David Hildenbrand > Signed-off-by: Miaohe Lin > --- > mm/swap_state.c | 17 ----------------- > 1 file changed, 17 deletions(-) > > diff --git a/mm/swap_state.c b/mm/swap_state.c > index 0a2021fc55ad..41c6a6053d5c 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -59,24 +59,11 @@ static bool enable_vma_readahead __read_mostly = true; > #define GET_SWAP_RA_VAL(vma) \ > (atomic_long_read(&(vma)->swap_readahead_info) ? : 4) > > -#define INC_CACHE_INFO(x) data_race(swap_cache_info.x++) > -#define ADD_CACHE_INFO(x, nr) data_race(swap_cache_info.x += (nr)) > - > -static struct { > - unsigned long add_total; > - unsigned long del_total; > - unsigned long find_success; > - unsigned long find_total; > -} swap_cache_info; > - > static atomic_t swapin_readahead_hits = ATOMIC_INIT(4); > > void show_swap_cache_info(void) > { > printk("%lu pages in swap cache\n", total_swapcache_pages()); > - printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu\n", > - swap_cache_info.add_total, swap_cache_info.del_total, > - swap_cache_info.find_success, swap_cache_info.find_total); > printk("Free swap = %ldkB\n", > get_nr_swap_pages() << (PAGE_SHIFT - 10)); > printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10)); > @@ -133,7 +120,6 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, > address_space->nrpages += nr; > __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr); > __mod_lruvec_page_state(page, NR_SWAPCACHE, nr); > - ADD_CACHE_INFO(add_total, nr); > unlock: > xas_unlock_irq(&xas); > } while (xas_nomem(&xas, gfp)); > @@ -172,7 +158,6 @@ void __delete_from_swap_cache(struct page *page, > address_space->nrpages -= nr; > __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, -nr); > __mod_lruvec_page_state(page, NR_SWAPCACHE, -nr); > - ADD_CACHE_INFO(del_total, nr); > } > > /** > @@ -348,12 +333,10 @@ struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, > page = find_get_page(swap_address_space(entry), swp_offset(entry)); > put_swap_device(si); > > - INC_CACHE_INFO(find_total); > if (page) { > bool vma_ra = swap_use_vma_readahead(); > bool readahead; > > - INC_CACHE_INFO(find_success); > /* > * At the moment, we don't support PG_readahead for anon THP > * so let's bail out rather than confusing the readahead stat. This looks reasonable. And if we want to do some statistics for swap cache in the future, we can use BPF, that is even more convenient. Acked-by: "Huang, Ying" Best Regards, Huang, Ying