From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by kanga.kvack.org (Postfix) with ESMTP id 191D56B0038 for ; Thu, 29 Jan 2015 00:28:36 -0500 (EST) Received: by mail-pa0-f54.google.com with SMTP id eu11so34505812pac.13 for ; Wed, 28 Jan 2015 21:28:35 -0800 (PST) Received: from mail-pa0-x235.google.com (mail-pa0-x235.google.com. [2607:f8b0:400e:c03::235]) by mx.google.com with ESMTPS id hl8si8384094pad.210.2015.01.28.21.28.35 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 28 Jan 2015 21:28:35 -0800 (PST) Received: by mail-pa0-f53.google.com with SMTP id kx10so34474094pab.12 for ; Wed, 28 Jan 2015 21:28:34 -0800 (PST) Date: Thu, 29 Jan 2015 14:28:27 +0900 From: Minchan Kim Subject: Re: [PATCH v1 2/2] zram: remove init_lock in zram_make_request Message-ID: <20150129052827.GB25462@blaptop> References: <1422432945-6764-1-git-send-email-minchan@kernel.org> <1422432945-6764-2-git-send-email-minchan@kernel.org> <20150128145651.GB965@swordfish> <20150128233343.GC4706@blaptop> <20150129020139.GB9672@blaptop> <20150129022241.GA2555@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150129022241.GA2555@swordfish> Sender: owner-linux-mm@kvack.org List-ID: To: Sergey Senozhatsky Cc: Sergey Senozhatsky , Andrew Morton , "linux-kernel@vger.kernel.org" , Linux-MM , Nitin Gupta , Jerome Marchand , Ganesh Mahendran On Thu, Jan 29, 2015 at 11:22:41AM +0900, Sergey Senozhatsky wrote: > On (01/29/15 11:01), Minchan Kim wrote: > > On Thu, Jan 29, 2015 at 10:57:38AM +0900, Sergey Senozhatsky wrote: > > > On Thu, Jan 29, 2015 at 8:33 AM, Minchan Kim wrote: > > > > On Wed, Jan 28, 2015 at 11:56:51PM +0900, Sergey Senozhatsky wrote: > > > > > I don't like re-introduced ->init_done. > > > > > another idea... how about using `zram->disksize == 0' instead of > > > > > `->init_done' (previously `->meta != NULL')? should do the trick. > > > > > > > > It could be. > > > > > > > > > > > care to change it? > > > > Will try! > > > > If it was your concern, I'm happy to remove the check.(ie, actually, > > I realized that after I push the button to send). Thanks! > > > > Thanks a lot, Minchan. > > and, guys, sorry for previous html email (I'm sure I toggled the "plain > text" mode in gmail web-interface, but somehow it has different meaning > in gmail world). > > > I'm still concerned about performance numbers that I see on my x86_64. > it's not always, but mostly slower. I'll give it another try (disable > lockdep, etc.), but if we lose 10% on average then, sorry, I'm not so > positive about srcu change and will tend to vote for your initial commit > that simply moved meta free() out of init_lock and left locking as is > (lockdep warning would have been helpful there, because otherwise it > just looked like we change code w/o any reason). > > what do you thunk? Surely I agreee with you. If it suffers from 10% performance regression, it's absolutely no go. However, I believe it should be no loss because that's one of the reason from RCU birth which should be really win in read-side lock path compared to other locking. Please test it with dd or something for block-based test for removing noise from FS. I also will test it to confirm that with real machine. Thanks for the review! > > -ss -- Kind regards, Minchan Kim -- 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