From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Moyer Subject: Re: [RFC][PATCH v3 4/6] aio: Don't inherit aio ring memory at fork Date: Tue, 14 Apr 2009 12:01:50 -0400 Message-ID: References: <20090414151204.C647.A69D9226@jp.fujitsu.com> <20090414151924.C653.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: LKML , Zach Brown , Jens Axboe , linux-api@vger.kernel.org, Linus Torvalds , Andrew Morton , Nick Piggin , Andrea Arcangeli , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org To: KOSAKI Motohiro Return-path: In-Reply-To: <20090414151924.C653.A69D9226@jp.fujitsu.com> (KOSAKI Motohiro's message of "Tue, 14 Apr 2009 15:20:20 +0900 (JST)") Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org KOSAKI Motohiro writes: > AIO folks, Am I missing anything? > > =============== > Subject: [RFC][PATCH] aio: Don't inherit aio ring memory at fork > > Currently, mm_struct::ioctx_list member isn't copyed at fork. IOW aio context don't inherit at fork. > but only ring memory inherited. that's strange. > > This patch mark DONTFORK to ring-memory too. Well, given that clearly nobody relies on io contexts being copied to the child, I think it's okay to make this change. I think the current behaviour violates the principal of least surprise, but I'm having a hard time getting upset about that. ;) > In addition, This patch has good side effect. it also fix > "get_user_pages() vs fork" problem. Hmm, I don't follow you, here. As I understand it, the get_user_pages vs. fork problem has to do with the pages used for the actual I/O, not the pages used to store the completion data. So, could you elaborate a bit on what you mean by the above statement? > I think "man fork" also sould be changed. it only say > > * The child does not inherit outstanding asynchronous I/O operations from > its parent (aio_read(3), aio_write(3)). > but aio_context_t (return value of io_setup(2)) also don't inherit in current implementaion. I can certainly make that change, as I have other changes I need to push to Michael, anyway. Cheers, Jeff -- 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