From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Subject: Re: [PATCH v2 14/18] x86/sgx: Add EPC OOM path to forcefully reclaim EPC Date: Mon, 12 Dec 2022 18:09:39 +0000 Message-ID: References: <20221202183655.3767674-1-kristen@linux.intel.com> <20221202183655.3767674-15-kristen@linux.intel.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=caT/eR3o2xI61xv4gQNQ+fDkRVtZB1sOkBNJmlEN+N4=; b=btZ4GA2g/VsRjxBZWyd9Ot4NYl23XggbHAYppoWAJmTxlei8M5/a+b75/69vjs6/GH I6tP0ipoDef613AM61HoV+CINKngTjD8WS0TtXzjvi7PemuFIO0aVViEu8P6/zlMroeA /rz2PU13KL9/wCcPniQNnwBMvXDHGjycV7BnTq/mTjEiO803KNc18d/0d7ajvdY3QB7c 0dxIjjg5xtkMMm5gLHj3U0CnOt1GX8A52AptPekUmyPv2lyy1JN1gm/Yf/39hMlDWIAm iDow4z0quQ16cubZl80/hIZjTver2Aez811DpWbpe/dWEi1fggZISJ8ob8bsgCwH30Wl Vy1Q== Content-Disposition: inline In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dave Hansen Cc: Kristen Carlson Accardi , Jarkko Sakkinen , dave.hansen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sgx-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "H. Peter Anvin" , zhiquan1.li-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org On Fri, Dec 09, 2022, Dave Hansen wrote: > On 12/9/22 08:05, Kristen Carlson Accardi wrote: > > Aside from that though, I don't think that killing enclaves makes sense > > outside the context of cgroup limits. > > I think it makes a lot of sense in theory. Whatever situation we get > into with a cgroup's EPC we can also get into with the whole system's EPC. > > *But*, it's orders of magnitude harder to hit on the whole system. ... > If someone wants to extend this OOM support to system-wide EPC later, then go > ahead. But, I don't think it makes a lot of sense to invert this series for > it. +1 from the peanut gallery. With VMM EPC oversubscription suport, no sane VMM will oversubscribe VEPC pages. And for VA pages, supporting swap of VA pages is likely a more userspace-friendly approach if system-wide EPC OOM is a concern. 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[34.168.104.7]) by smtp.gmail.com with ESMTPSA id ep11-20020a17090ae64b00b00210c84b8ae5sm5717900pjb.35.2022.12.12.10.09.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Dec 2022 10:09:43 -0800 (PST) Date: Mon, 12 Dec 2022 18:09:39 +0000 From: Sean Christopherson To: Dave Hansen Cc: Kristen Carlson Accardi , Jarkko Sakkinen , dave.hansen@linux.intel.com, tj@kernel.org, linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org, cgroups@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , zhiquan1.li@intel.com Subject: Re: [PATCH v2 14/18] x86/sgx: Add EPC OOM path to forcefully reclaim EPC Message-ID: References: <20221202183655.3767674-1-kristen@linux.intel.com> <20221202183655.3767674-15-kristen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Fri, Dec 09, 2022, Dave Hansen wrote: > On 12/9/22 08:05, Kristen Carlson Accardi wrote: > > Aside from that though, I don't think that killing enclaves makes sense > > outside the context of cgroup limits. > > I think it makes a lot of sense in theory. Whatever situation we get > into with a cgroup's EPC we can also get into with the whole system's EPC. > > *But*, it's orders of magnitude harder to hit on the whole system. ... > If someone wants to extend this OOM support to system-wide EPC later, then go > ahead. But, I don't think it makes a lot of sense to invert this series for > it. +1 from the peanut gallery. With VMM EPC oversubscription suport, no sane VMM will oversubscribe VEPC pages. And for VA pages, supporting swap of VA pages is likely a more userspace-friendly approach if system-wide EPC OOM is a concern.