From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1FC19C433F5 for ; Wed, 16 Feb 2022 21:12:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8B2076B0074; Wed, 16 Feb 2022 16:12:11 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8620B6B0075; Wed, 16 Feb 2022 16:12:11 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 729286B0078; Wed, 16 Feb 2022 16:12:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 617106B0074 for ; Wed, 16 Feb 2022 16:12:11 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay11.hostedemail.com (Postfix) with ESMTP id 38797808F7 for ; Wed, 16 Feb 2022 21:12:11 +0000 (UTC) X-FDA: 79149890862.01.C404186 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf22.hostedemail.com (Postfix) with ESMTP id EECA4C0002 for ; Wed, 16 Feb 2022 21:12:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=D6yQWpPiZKOZJrzIf2axmO1rZEJsSNio9md1863l80s=; b=wMlACg0F12u85Oi9WbYXcXhlVp WNh1l5vleW/gdXc1ZmJyAj4GfUBnpnRmtGV0BF0FyB41VQk9UPX3DD9Gm9s/CSevLpXgEqQC/1p1n GlrpprsX/F0h/2AAZGKV5ACYmBNxDUNffbtdVrGtoEgvaw4GS9MqtXd2n3vaGJFVwZeYYn/x5T72A hVO7rngCqXOd6kBet/ObUUNSvhLbLCWe1Olx39dIltrErB+0MqQqL2BK4BkQE8/eGLhKeYAp9nrFB 9nYP23vqJd8Pv2LntIhK9OT6UOGBJ6I2YkUrLnB46a+3fMJ7nq6wszi7MfvgVHjiiwV+687bvvzpp rLoBe9WQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nKRaj-00F2ir-Am; Wed, 16 Feb 2022 21:12:01 +0000 Date: Wed, 16 Feb 2022 21:12:01 +0000 From: Matthew Wilcox To: Roman Gushchin Cc: Vasily Averin , Andrew Morton , Linux MM , Vlastimil Babka Subject: Re: tools/cgroup/memcg_slabinfo.py is broken Message-ID: References: <327b9e92-88bb-d66f-e07c-526161db539b@virtuozzo.com> <35486a00-791c-3b1b-14e0-476e6242709b@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: EECA4C0002 X-Stat-Signature: 6cynoqyfrc3ku7oa34ndz6nnqdbg3cex X-Rspam-User: Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=wMlACg0F; spf=none (imf22.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-HE-Tag: 1645045929-220893 X-Bogosity: Ham, tests=bogofilter, spamicity=0.010070, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Feb 16, 2022 at 12:52:36PM -0800, Roman Gushchin wrote: > The problem can be fixed by explicitly casting struct page * to struct > slab * for slab pages. The tools works as expected with this fix, e.g.: This feels like a quick fix, and not really correct. > @@ -77,7 +77,8 @@ def count_partial(n, fn): > > > def count_free(page): > - return page.objects - page.inuse > + slab = cast('struct slab *', page) > + return slab.objects - slab.inuse count_free() should take a slab, not a page. > def slub_get_slabinfo(s, cfg): > @@ -193,10 +194,11 @@ def main(): > # look over all slab pages, belonging to non-root memcgs > # and look for objects belonging to the given memory cgroup > for page in for_each_slab_page(prog): for_each_slab_page() should be renamed for_each_slab(). It should return a slab, not a page. And it should definitely skip over tail pages (it works today by coincidence because tail pages do not have PG_slab set). count_partial() should use struct slab, and slab_list, not lru. ... I think that's it. But I'm no pythonist, much less dragoneer.