From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id E9E146B0279 for ; Wed, 7 Jun 2017 00:58:47 -0400 (EDT) Received: by mail-pg0-f69.google.com with SMTP id e1so1107731pga.5 for ; Tue, 06 Jun 2017 21:58:47 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [45.249.212.188]) by mx.google.com with ESMTPS id u25si670623pfa.375.2017.06.06.21.58.46 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 06 Jun 2017 21:58:47 -0700 (PDT) Message-ID: <59378799.1050000@huawei.com> Date: Wed, 7 Jun 2017 12:56:57 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [PATCH] Revert "mm: vmpressure: fix sending wrong events on underflow" References: <1496804917-7628-1-git-send-email-zhongjiang@huawei.com> <20170607035540.GA5687@bbox> In-Reply-To: <20170607035540.GA5687@bbox> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: akpm@linux-foundation.org, vinayakm.list@gmail.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 2017/6/7 11:55, Minchan Kim wrote: > On Wed, Jun 07, 2017 at 11:08:37AM +0800, zhongjiang wrote: >> This reverts commit e1587a4945408faa58d0485002c110eb2454740c. >> >> THP lru page is reclaimed , THP is split to normal page and loop again. >> reclaimed pages should not be bigger than nr_scan. because of each >> loop will increase nr_scan counter. > Unfortunately, there is still underflow issue caused by slab pages as > Vinayak reported in description of e1587a4945408 so we cannot revert. > Please correct comment instead of removing the logic. > > Thanks. we calculate the vmpressue based on the Lru page, exclude the slab pages by previous discussion. is it not this? Thanks zhongjiang >> Signed-off-by: zhongjiang >> --- >> mm/vmpressure.c | 10 +--------- >> 1 file changed, 1 insertion(+), 9 deletions(-) >> >> diff --git a/mm/vmpressure.c b/mm/vmpressure.c >> index 6063581..149fdf6 100644 >> --- a/mm/vmpressure.c >> +++ b/mm/vmpressure.c >> @@ -112,16 +112,9 @@ static enum vmpressure_levels vmpressure_calc_level(unsigned long scanned, >> unsigned long reclaimed) >> { >> unsigned long scale = scanned + reclaimed; >> - unsigned long pressure = 0; >> + unsigned long pressure; >> >> /* >> - * reclaimed can be greater than scanned in cases >> - * like THP, where the scanned is 1 and reclaimed >> - * could be 512 >> - */ >> - if (reclaimed >= scanned) >> - goto out; >> - /* >> * We calculate the ratio (in percents) of how many pages were >> * scanned vs. reclaimed in a given time frame (window). Note that >> * time is in VM reclaimer's "ticks", i.e. number of pages >> @@ -131,7 +124,6 @@ static enum vmpressure_levels vmpressure_calc_level(unsigned long scanned, >> pressure = scale - (reclaimed * scale / scanned); >> pressure = pressure * 100 / scale; >> >> -out: >> pr_debug("%s: %3lu (s: %lu r: %lu)\n", __func__, pressure, >> scanned, reclaimed); >> >> -- >> 1.7.12.4 >> > . > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org