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 69698C4345F for ; Fri, 3 May 2024 09:26:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CDF366B0089; Fri, 3 May 2024 05:26:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C8F126B008C; Fri, 3 May 2024 05:26:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B57776B0092; Fri, 3 May 2024 05:26:16 -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 993F96B0089 for ; Fri, 3 May 2024 05:26:16 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 088A5A061A for ; 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imf13.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf13.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1714728374; a=rsa-sha256; cv=none; b=RchuLpxdY7ws6W4xgbGKBtG0ivLvGMVNbPXRnM6ngIx8/uOOK5uawclLPStygQrSb7r7gZ +sGU38r+rH8+a8iCZ9qapOtlwQ9Fv9FkDxAR05YbLI6KiQl34hjy0YXOH+8cdM5j707hjG MfB6b8CorzFKm1tSzFGNB/DrLPXfCZI= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B50692F4; Fri, 3 May 2024 02:26:38 -0700 (PDT) Received: from [10.57.67.51] (unknown [10.57.67.51]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D95153F73F; Fri, 3 May 2024 02:26:10 -0700 (PDT) Message-ID: Date: Fri, 3 May 2024 10:26:09 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/6] mm: swap: introduce swap_free_nr() for batched swap_free() Content-Language: en-GB To: Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org Cc: baolin.wang@linux.alibaba.com, chrisl@kernel.org, david@redhat.com, hanchuanhua@oppo.com, hannes@cmpxchg.org, hughd@google.com, kasong@tencent.com, linux-kernel@vger.kernel.org, surenb@google.com, v-songbaohua@oppo.com, willy@infradead.org, xiang@kernel.org, ying.huang@intel.com, yosryahmed@google.com, yuzhao@google.com, ziy@nvidia.com References: <20240503005023.174597-1-21cnbao@gmail.com> <20240503005023.174597-2-21cnbao@gmail.com> From: Ryan Roberts In-Reply-To: <20240503005023.174597-2-21cnbao@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 40D6D2000B X-Stat-Signature: u3s16y8qfutqxmf8j5oti9eoxeq3zjs3 X-Rspam-User: X-HE-Tag: 1714728374-47413 X-HE-Meta: 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 HUIcxYnd ctvUFId8/fWKllFRQs0zYTxeMCLZmYnaReDxkD13gTt2Ys7ZW2cPnVaARq5dKbz+CAS/iIuyVfMofyESX/TSZ8OXCeSnqlJobqWKbCuCypE6pFSmECdcl4mv3xh3qGkYOPtz3Wrfd70hyJI/1mTbadSC4dPTGV2JnNQrygaE3ndrViUcci69h5XrFLHl1FhvlL2Jssd9GOcHCG1xid3zvpJYDP9g3vPUD5ik2QjLyhzgVRQkEEGrZHLd8eBTtr2mUJwsWrBSNNeB3yjmmmzFkIklVjwa1h1N56etICl3vnZcDJ8rY1sGv0sEpsg== 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: List-Subscribe: List-Unsubscribe: On 03/05/2024 01:50, Barry Song wrote: > From: Chuanhua Han > > While swapping in a large folio, we need to free swaps related to the whole > folio. To avoid frequently acquiring and releasing swap locks, it is better > to introduce an API for batched free. > Furthermore, this new function, swap_free_nr(), is designed to efficiently > handle various scenarios for releasing a specified number, nr, of swap > entries. > > Signed-off-by: Chuanhua Han > Co-developed-by: Barry Song > Signed-off-by: Barry Song This looks much better! Reviewed-by: Ryan Roberts > --- > include/linux/swap.h | 5 +++++ > mm/swapfile.c | 47 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 52 insertions(+) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index 11c53692f65f..d1d35e92d7e9 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -483,6 +483,7 @@ extern void swap_shmem_alloc(swp_entry_t); > extern int swap_duplicate(swp_entry_t); > extern int swapcache_prepare(swp_entry_t); > extern void swap_free(swp_entry_t); > +extern void swap_free_nr(swp_entry_t entry, int nr_pages); > extern void swapcache_free_entries(swp_entry_t *entries, int n); > extern void free_swap_and_cache_nr(swp_entry_t entry, int nr); > int swap_type_of(dev_t device, sector_t offset); > @@ -564,6 +565,10 @@ static inline void swap_free(swp_entry_t swp) > { > } > > +static inline void swap_free_nr(swp_entry_t entry, int nr_pages) > +{ > +} > + > static inline void put_swap_folio(struct folio *folio, swp_entry_t swp) > { > } > diff --git a/mm/swapfile.c b/mm/swapfile.c > index f6ca215fb92f..ec12f2b9d229 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -1356,6 +1356,53 @@ void swap_free(swp_entry_t entry) > __swap_entry_free(p, entry); > } > > +static void cluster_swap_free_nr(struct swap_info_struct *sis, > + unsigned long offset, int nr_pages) > +{ > + struct swap_cluster_info *ci; > + DECLARE_BITMAP(to_free, BITS_PER_LONG) = { 0 }; > + int i, nr; > + > + ci = lock_cluster_or_swap_info(sis, offset); > + while (nr_pages) { > + nr = min(BITS_PER_LONG, nr_pages); > + for (i = 0; i < nr; i++) { > + if (!__swap_entry_free_locked(sis, offset + i, 1)) > + bitmap_set(to_free, i, 1); > + } > + if (!bitmap_empty(to_free, BITS_PER_LONG)) { > + unlock_cluster_or_swap_info(sis, ci); > + for_each_set_bit(i, to_free, BITS_PER_LONG) > + free_swap_slot(swp_entry(sis->type, offset + i)); > + if (nr == nr_pages) > + return; > + bitmap_clear(to_free, 0, BITS_PER_LONG); > + ci = lock_cluster_or_swap_info(sis, offset); > + } > + offset += nr; > + nr_pages -= nr; > + } > + unlock_cluster_or_swap_info(sis, ci); > +} > + > +void swap_free_nr(swp_entry_t entry, int nr_pages) > +{ > + int nr; > + struct swap_info_struct *sis; > + unsigned long offset = swp_offset(entry); > + > + sis = _swap_info_get(entry); > + if (!sis) > + return; > + > + while (nr_pages) { > + nr = min_t(int, nr_pages, SWAPFILE_CLUSTER - offset % SWAPFILE_CLUSTER); > + cluster_swap_free_nr(sis, offset, nr); > + offset += nr; > + nr_pages -= nr; > + } > +} > + > /* > * Called after dropping swapcache to decrease refcnt to swap entries. > */