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 0B6A2C77B75 for ; Wed, 10 May 2023 01:49:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235413AbjEJBtv (ORCPT ); Tue, 9 May 2023 21:49:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229549AbjEJBtu (ORCPT ); Tue, 9 May 2023 21:49:50 -0400 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 301DA3A85 for ; Tue, 9 May 2023 18:49:48 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R701e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046056;MF=xhao@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0ViDRxzG_1683683383; Received: from 30.240.106.49(mailfrom:xhao@linux.alibaba.com fp:SMTPD_---0ViDRxzG_1683683383) by smtp.aliyun-inc.com; Wed, 10 May 2023 09:49:45 +0800 Message-ID: <432c0505-301f-9abb-6e99-0dc216913122@linux.alibaba.com> Date: Wed, 10 May 2023 09:49:42 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH 1/2] migrate_pages_batch: simplify retrying and failure counting of large folios To: Huang Ying , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zi Yan , Yang Shi , Baolin Wang , Oscar Salvador , Alistair Popple References: <20230509022014.380493-1-ying.huang@intel.com> From: haoxin In-Reply-To: <20230509022014.380493-1-ying.huang@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2023/5/9 上午10:20, Huang Ying 写道: > After recent changes to the retrying and failure counting in > migrate_pages_batch(), it was found that it's unnecessary to count > retrying and failure for normal, large, and THP folios separately. > Because we don't use retrying and failure number of large folios > directly. So, in this patch, we simplified retrying and failure > counting of large folios via counting retrying and failure of normal > and large folios together. This results in the reduced line number. > > This is just code cleanup, no functionality changes are expected. > > Signed-off-by: "Huang, Ying" > Cc: Xin Hao > Cc: Zi Yan > Cc: Yang Shi > Cc: Baolin Wang > Cc: Oscar Salvador > Cc: Alistair Popple > --- > mm/migrate.c | 103 +++++++++++++++++---------------------------------- > 1 file changed, 35 insertions(+), 68 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 01cac26a3127..10709aed76d3 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1614,11 +1614,9 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > int nr_pass) > { > int retry = 1; > - int large_retry = 1; > int thp_retry = 1; > int nr_failed = 0; > int nr_retry_pages = 0; > - int nr_large_failed = 0; > int pass = 0; > bool is_large = false; > bool is_thp = false; > @@ -1631,9 +1629,8 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > VM_WARN_ON_ONCE(mode != MIGRATE_ASYNC && > !list_empty(from) && !list_is_singular(from)); > > - for (pass = 0; pass < nr_pass && (retry || large_retry); pass++) { > + for (pass = 0; pass < nr_pass && retry; pass++) { > retry = 0; > - large_retry = 0; > thp_retry = 0; > nr_retry_pages = 0; > > @@ -1660,7 +1657,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > * list is processed. > */ > if (!thp_migration_supported() && is_thp) { > - nr_large_failed++; > + nr_failed++; > stats->nr_thp_failed++; > if (!try_split_folio(folio, split_folios)) { > stats->nr_thp_split++; > @@ -1688,38 +1685,33 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > * When memory is low, don't bother to try to migrate > * other folios, move unmapped folios, then exit. > */ > - if (is_large) { > - nr_large_failed++; > - stats->nr_thp_failed += is_thp; > - /* Large folio NUMA faulting doesn't split to retry. */ > - if (!nosplit) { > - int ret = try_split_folio(folio, split_folios); > - > - if (!ret) { > - stats->nr_thp_split += is_thp; > - break; > - } else if (reason == MR_LONGTERM_PIN && > - ret == -EAGAIN) { > - /* > - * Try again to split large folio to > - * mitigate the failure of longterm pinning. > - */ > - large_retry++; > - thp_retry += is_thp; > - nr_retry_pages += nr_pages; > - /* Undo duplicated failure counting. */ > - nr_large_failed--; > - stats->nr_thp_failed -= is_thp; > - break; > - } > + nr_failed++; > + stats->nr_thp_failed += is_thp; > + /* Large folio NUMA faulting doesn't split to retry. */ > + if (is_large && !nosplit) { > + int ret = try_split_folio(folio, split_folios); > + > + if (!ret) { > + stats->nr_thp_split += is_thp; > + break; > + } else if (reason == MR_LONGTERM_PIN && > + ret == -EAGAIN) { > + /* > + * Try again to split large folio to > + * mitigate the failure of longterm pinning. > + */ > + retry++; > + thp_retry += is_thp; > + nr_retry_pages += nr_pages; > + /* Undo duplicated failure counting. */ > + nr_failed--; > + stats->nr_thp_failed -= is_thp; > + break; > } > - } else { > - nr_failed++; > } > > stats->nr_failed_pages += nr_pages + nr_retry_pages; > /* nr_failed isn't updated for not used */ > - nr_large_failed += large_retry; > stats->nr_thp_failed += thp_retry; > rc_saved = rc; > if (list_empty(&unmap_folios)) > @@ -1727,12 +1719,8 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > else > goto move; > case -EAGAIN: > - if (is_large) { > - large_retry++; > - thp_retry += is_thp; > - } else { > - retry++; > - } > + retry++; > + thp_retry += is_thp; > nr_retry_pages += nr_pages; > break; > case MIGRATEPAGE_SUCCESS: > @@ -1750,20 +1738,14 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > * removed from migration folio list and not > * retried in the next outer loop. > */ > - if (is_large) { > - nr_large_failed++; > - stats->nr_thp_failed += is_thp; > - } else { > - nr_failed++; > - } > - > + nr_failed++; > + stats->nr_thp_failed += is_thp; > stats->nr_failed_pages += nr_pages; > break; > } > } > } > nr_failed += retry; > - nr_large_failed += large_retry; > stats->nr_thp_failed += thp_retry; > stats->nr_failed_pages += nr_retry_pages; > move: > @@ -1771,17 +1753,15 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > try_to_unmap_flush(); > > retry = 1; > - for (pass = 0; pass < nr_pass && (retry || large_retry); pass++) { > + for (pass = 0; pass < nr_pass && retry; pass++) { > retry = 0; > - large_retry = 0; > thp_retry = 0; > nr_retry_pages = 0; > > dst = list_first_entry(&dst_folios, struct folio, lru); > dst2 = list_next_entry(dst, lru); > list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { > - is_large = folio_test_large(folio); > - is_thp = is_large && folio_test_pmd_mappable(folio); > + is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); > nr_pages = folio_nr_pages(folio); > > cond_resched(); > @@ -1797,12 +1777,8 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > */ > switch(rc) { > case -EAGAIN: > - if (is_large) { > - large_retry++; > - thp_retry += is_thp; > - } else { > - retry++; > - } > + retry++; > + thp_retry += is_thp; > nr_retry_pages += nr_pages; > break; > case MIGRATEPAGE_SUCCESS: > @@ -1810,13 +1786,8 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > stats->nr_thp_succeeded += is_thp; > break; > default: > - if (is_large) { > - nr_large_failed++; > - stats->nr_thp_failed += is_thp; > - } else { > - nr_failed++; > - } > - > + nr_failed++; > + stats->nr_thp_failed += is_thp; > stats->nr_failed_pages += nr_pages; > break; > } > @@ -1825,14 +1796,10 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > } > } > nr_failed += retry; > - nr_large_failed += large_retry; > stats->nr_thp_failed += thp_retry; > stats->nr_failed_pages += nr_retry_pages; > > - if (rc_saved) > - rc = rc_saved; > - else > - rc = nr_failed + nr_large_failed; > + rc = rc_saved ? : nr_failed; > out: > /* Cleanup remaining folios */ > dst = list_first_entry(&dst_folios, struct folio, lru); LGTM. Reviewed-by: Xin Hao