From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 5EB0F90A46 for ; Fri, 23 Sep 2022 09:58:20 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 31D5220D55 for ; Fri, 23 Sep 2022 09:58:20 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Fri, 23 Sep 2022 09:58:18 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id AE28944591 for ; Fri, 23 Sep 2022 09:58:18 +0200 (CEST) Date: Fri, 23 Sep 2022 09:58:17 +0200 From: Wolfgang Bumiller To: Dominik Csapak Cc: Matthias Heiserer , Proxmox VE development discussion Message-ID: <20220923075817.pdtt6ko3ukaygzno@wobu-vie.proxmox.com> References: <20220921124911.3224970-1-d.csapak@proxmox.com> <20220921124911.3224970-3-d.csapak@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-SPAM-LEVEL: Spam detection results: 0 AWL 0.262 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pve-devel] [PATCH qemu-server 2/3] qmeventd: cancel 'forced cleanup' when normal cleanup succeeds X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Sep 2022 07:58:20 -0000 On Thu, Sep 22, 2022 at 01:37:57PM +0200, Dominik Csapak wrote: > On 9/22/22 12:14, Matthias Heiserer wrote: > > On 21.09.2022 14:49, Dominik Csapak wrote: > > > instead of always sending a SIGKILL to the target pid. > > > It was not that much of a problem since the timeout previously was 5 > > > seconds and we used pifds where possible, thus the chance of killing the > > > wrong process was rather slim. > > > > > > Now we increased the timeout to 60s which makes the race a bit more likely > > > (when not using pidfds), so remove it from the 'forced_cleanups' list when > > > the normal cleanup succeeds. > > > > > > Signed-off-by: Dominik Csapak > > > --- > > >   qmeventd/qmeventd.c | 20 ++++++++++++++++++++ > > >   1 file changed, 20 insertions(+) > > > > > > diff --git a/qmeventd/qmeventd.c b/qmeventd/qmeventd.c > > > index e9ff5b3..de5efd0 100644 > > > --- a/qmeventd/qmeventd.c > > > +++ b/qmeventd/qmeventd.c > > > @@ -415,6 +415,25 @@ cleanup_qemu_client(struct Client *client) > > >       } > > >   } > > > +static void > > > +remove_cleanup_data(void *ptr, void *client_ptr) { > > Not that it really matters, but is there a reason we don't use > > remove_cleanup_data(struct CleanupData *ptr, struct Client *client_ptr) > > and let the caller deal with types? > > > +    struct CleanupData *data = (struct CleanupData *)ptr; > > > +    struct Client *client = (struct Client *)client_ptr; > > > + > > > +    if (data->pid == client->pid) { > > > +    forced_cleanups = g_slist_remove(forced_cleanups, ptr); > > > +    free(ptr); > > > +    } > > > +} > > > + > +static void > > > +remove_from_forced_cleanup(struct Client *client) { > > > +    if (g_slist_length(forced_cleanups) > 0) { > > > +    VERBOSE_PRINT("removing %s from forced cleanups\n", client->qemu.vmid); > > > +    g_slist_foreach(forced_cleanups, remove_cleanup_data, client); > > that is, here `(void (*)(void*, void*)) remove_cleanup_data`. Seems a bit cleaner to me. > > > +    } > > > +} > > > + > > >   void > > >   cleanup_client(struct Client *client) > > >   { > > > @@ -441,6 +460,7 @@ cleanup_client(struct Client *client) > > >           break; > > >       } > > > +    remove_from_forced_cleanup(client); > > >       free(client); > > >   } > > > > i just kept the style we use for the existing call to *_foreach. > > my guess is that the intention was to keep the function close to what glib defines > (although that uses 'gpointer'). doing as you suggested introduces a big > cast that is confusing to read IMHO (for people not that familiar with c at least ;) ) > that could be solved with casting to 'GFunc' (not sure if that's considered good style?) > but in the end, i don't have strong feeling either way Just to follow this up: The main argument I can give for the current style is that a cast works for any function signature and therefor removes one possible compile-time check. Sure, you can mess up the parameter cast in the function body, but that's arguably less likely. Also, since they're usually `void*` you wouldn't actually *need* to repeat the type in the function body: -struct CleanupData *data = (struct CleanupData *)ptr; +struct CleanupData *data = ptr; is actually sufficient in C.