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 4EBD9C433EF for ; Thu, 17 Feb 2022 01:27:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230343AbiBQB1Z (ORCPT ); Wed, 16 Feb 2022 20:27:25 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:34556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230354AbiBQB1V (ORCPT ); Wed, 16 Feb 2022 20:27:21 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F23B9C2E7E for ; Wed, 16 Feb 2022 17:27:07 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8F07961CAC for ; Thu, 17 Feb 2022 01:27:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD014C004E1; Thu, 17 Feb 2022 01:27:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1645061227; bh=SwqgJYPOMEPTFnBF9nLrxggrtKVkR5YBdzjqlbKMJ+Q=; h=Date:To:From:Subject:From; b=t+Rwv1rLrGCnTw/NFmNMwWklUgNprr2o2HMTjEX85dWCBcBFFIfELWiqDCKiJ8hOU ZA8gnvroTpyo8krq3hiZbCoY6K7mQ8Aeqke9zWXorwBhz9oA/QroIH9KEMq5Od0+b2 vMLFtaepcB01T99mB73lRuCObCdBQoneIPsr/bJs= Date: Wed, 16 Feb 2022 17:27:06 -0800 To: mm-commits@vger.kernel.org, vbabka@suse.cz, mhocko@kernel.org, dave.hansen@linux.intel.com, brouer@redhat.com, aaron.lu@intel.com, mgorman@techsingularity.net, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch added to -mm tree Message-Id: <20220217012706.DD014C004E1@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/page_alloc: simplify how many pages are selected per pcp list during bulk free has been added to the -mm tree. Its filename is mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Mel Gorman Subject: mm/page_alloc: simplify how many pages are selected per pcp list during bulk free free_pcppages_bulk() selects pages to free by round-robining between lists. Originally this was to evenly shrink pages by migratetype but uneven freeing is inevitable due to high pages. Simplify list selection by starting with a list that definitely has pages on it in free_unref_page_commit() and for drain, it does not matter where draining starts as all pages are removed. Link: https://lkml.kernel.org/r/20220217002227.5739-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman Reviewed-by: Vlastimil Babka Cc: Aaron Lu Cc: Dave Hansen Cc: Jesper Dangaard Brouer Cc: Michal Hocko Signed-off-by: Andrew Morton --- mm/page_alloc.c | 34 +++++++++++----------------------- 1 file changed, 11 insertions(+), 23 deletions(-) --- a/mm/page_alloc.c~mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free +++ a/mm/page_alloc.c @@ -1447,13 +1447,11 @@ static inline void prefetch_buddy(struct * count is the number of pages to free. */ static void free_pcppages_bulk(struct zone *zone, int count, - struct per_cpu_pages *pcp) + struct per_cpu_pages *pcp, + int pindex) { - int pindex = 0; int min_pindex = 0; int max_pindex = NR_PCP_LISTS - 1; - int batch_free = 0; - int nr_freed = 0; unsigned int order; int prefetch_nr = READ_ONCE(pcp->batch); bool isolated_pageblocks; @@ -1467,16 +1465,10 @@ static void free_pcppages_bulk(struct zo count = min(pcp->count, count); while (count > 0) { struct list_head *list; + int nr_pages; - /* - * Remove pages from lists in a round-robin fashion. A - * batch_free count is maintained that is incremented when an - * empty list is encountered. This is so more pages are freed - * off fuller lists instead of spinning excessively around empty - * lists - */ + /* Remove pages from lists in a round-robin fashion. */ do { - batch_free++; if (++pindex > max_pindex) pindex = min_pindex; list = &pcp->lists[pindex]; @@ -1489,18 +1481,15 @@ static void free_pcppages_bulk(struct zo min_pindex++; } while (1); - /* This is the only non-empty list. Free them all. */ - if (batch_free >= max_pindex - min_pindex) - batch_free = count; - order = pindex_to_order(pindex); + nr_pages = 1 << order; BUILD_BUG_ON(MAX_ORDER >= (1<lru); - nr_freed += 1 << order; - count -= 1 << order; + count -= nr_pages; + pcp->count -= nr_pages; if (bulkfree_pcp_prepare(page)) continue; @@ -1524,9 +1513,8 @@ static void free_pcppages_bulk(struct zo prefetch_buddy(page, order); prefetch_nr--; } - } while (count > 0 && --batch_free && !list_empty(list)); + } while (count > 0 && !list_empty(list)); } - pcp->count -= nr_freed; /* * local_lock_irq held so equivalent to spin_lock_irqsave for @@ -3133,7 +3121,7 @@ void drain_zone_pages(struct zone *zone, batch = READ_ONCE(pcp->batch); to_drain = min(pcp->count, batch); if (to_drain > 0) - free_pcppages_bulk(zone, to_drain, pcp); + free_pcppages_bulk(zone, to_drain, pcp, 0); local_unlock_irqrestore(&pagesets.lock, flags); } #endif @@ -3154,7 +3142,7 @@ static void drain_pages_zone(unsigned in pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu); if (pcp->count) - free_pcppages_bulk(zone, pcp->count, pcp); + free_pcppages_bulk(zone, pcp->count, pcp, 0); local_unlock_irqrestore(&pagesets.lock, flags); } @@ -3435,7 +3423,7 @@ static void free_unref_page_commit(struc if (pcp->count >= high) { int batch = READ_ONCE(pcp->batch); - free_pcppages_bulk(zone, nr_pcp_free(pcp, high, batch), pcp); + free_pcppages_bulk(zone, nr_pcp_free(pcp, high, batch), pcp, pindex); } } _ Patches currently in -mm which might be from mgorman@techsingularity.net are mm-page_alloc-fetch-the-correct-pcp-buddy-during-bulk-free.patch mm-page_alloc-track-range-of-active-pcp-lists-during-bulk-free.patch mm-page_alloc-simplify-how-many-pages-are-selected-per-pcp-list-during-bulk-free.patch mm-page_alloc-drain-the-requested-list-first-during-bulk-free.patch mm-page_alloc-free-pages-in-a-single-pass-during-bulk-free.patch mm-page_alloc-limit-number-of-high-order-pages-on-pcp-during-bulk-free.patch