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Sun, 23 Oct 2022 06:11:30 -0700 (PDT) Date: Sun, 23 Oct 2022 13:11:29 +0000 From: Wei Yang To: Wei Yang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, Mel Gorman , Daero Lee Subject: Re: [PATCH] mm/vmscan: reduce double-check if kswapd is not able to sleep Message-ID: <20221023131129.jba6qq64ho45gdnn@master> Reply-To: Wei Yang References: <20221023080431.30893-1-richard.weiyang@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221023080431.30893-1-richard.weiyang@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666530692; a=rsa-sha256; cv=none; b=WVzYdFKvFdwYRU0i4gb8gKtByO9O+sRwusZP44DyF6wizHdZaU/yGey4TkrEzWk1BqFDql 2MMQ5poh71mMPORBSNMjzStgkiUxNdvNWbrJ0enoCqXlomtiR4XAJUmutJkzPByzw3o2Mu h0odi0LBBKI2d5hsKA/MrItbrYcWcLY= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=K9N9lmrR; spf=pass (imf19.hostedemail.com: domain of richard.weiyang@gmail.com designates 209.85.208.51 as permitted sender) smtp.mailfrom=richard.weiyang@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666530692; h=from:from:sender:reply-to: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=6ayFaQY5hoFXXpu6yL5VLXxi378Uc/Hl/bRvafnqUCw=; b=FOtt1uR6SjMD6WA9GqUo6pme37O4Zd3x5rIpHYZKdE/+fp0t55LZmNZc5VavjYCBySP2/0 WH2USqXGhnwDe1xXck/AiLh+b4Pv1WnoQezrnt8+71Qoht1ejfwSBUHtQXzWS9nmEtcG2I A0dK563cueHBVdOyb1oAesx0Zmi4ZEc= X-Stat-Signature: t5sspyo557re9gn3xboz7ubntmnhbki1 X-Rspamd-Queue-Id: 304A11A0005 Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=K9N9lmrR; spf=pass (imf19.hostedemail.com: domain of richard.weiyang@gmail.com designates 209.85.208.51 as permitted sender) smtp.mailfrom=richard.weiyang@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1666530691-282971 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: On Sun, Oct 23, 2022 at 08:04:31AM +0000, Wei Yang wrote: >In function kswapd_try_to_sleep, there are two phases for kswapd to >sleep: > > * premature sleep > * fully sleep > >For each phase we need to check whether kswapd is fine to sleep. > >While if it doesn't pass the check for first phase, it is not necessary >to do the check again. > >Signed-off-by: Wei Yang >CC: Mel Gorman >CC: Daero Lee > >--- >The original thread is >https://lkml.kernel.org/lkml/20220106094650.GX3366@techsingularity.net/T/, >but seems no further following up. > >So I pick it up. > >Mel, > >I just see your mail, sorry for the late reply :-( >--- > mm/vmscan.c | 18 ++++++++++++------ > 1 file changed, 12 insertions(+), 6 deletions(-) > >diff --git a/mm/vmscan.c b/mm/vmscan.c >index 04d8b88e5216..5a50b5908c4c 100644 >--- a/mm/vmscan.c >+++ b/mm/vmscan.c >@@ -7179,7 +7179,8 @@ static enum zone_type kswapd_highest_zoneidx(pg_data_t *pgdat, > static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_order, > unsigned int highest_zoneidx) > { >- long remaining = 0; >+ long remaining; Hmm... I am afraid remaining should still be init to 0, otherwise count_vm_event() may record a wrong event. -- Wei Yang Help you, Help me