From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from s3.sipsolutions.net ([2a01:4f8:191:4433::2] helo=sipsolutions.net) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1khfb3-0008Rm-Tl for linux-um@lists.infradead.org; Tue, 24 Nov 2020 21:11:34 +0000 Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.94) (envelope-from ) id 1khfb1-00E4yS-1G for linux-um@lists.infradead.org; Tue, 24 Nov 2020 22:11:31 +0100 Message-ID: <69ebf6160ddab9903203e76b5749949e5dc863fa.camel@sipsolutions.net> Subject: Re: [PATCH 0/7 um: IRQ handling cleanups From: Johannes Berg Date: Tue, 24 Nov 2020 22:11:30 +0100 In-Reply-To: <20201123195621.275470-1-johannes@sipsolutions.net> References: <20201123195621.275470-1-johannes@sipsolutions.net> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: linux-um@lists.infradead.org On Mon, 2020-11-23 at 20:56 +0100, Johannes Berg wrote: > The IRQ code seems very confusing, but now that I've had to dig > through it, I've come up with a number of cleanups. Really what > I wanted was suspend/resume support (next series), but this is > all necessary for that, in particular for virtio resume support > (still WIP). Btw. It seems to me that we really ought to implement IRQ masking and unmasking correctly. I've run into a number of scenarios now where we can never return from sigio_handler() because an FD is readable (or writeable) and thus we got SIGIO, but then it doesn't *stop* being readable (writeable) because the actual interrupt handler isn't run. I hit this in suspend, but perhaps there are other reasons why we might never get to the interrupt handler (irq_may_run())? In any case, I did solve these issues by just doing the restore of interrupts late enough for now, and probably always munging the epoll mask is too expensive ... but it's definitely a caveat here. johannes _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um