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 64DD2C77B73 for ; Tue, 2 May 2023 17:39:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D88296B007E; Tue, 2 May 2023 13:39:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D38A76B0080; Tue, 2 May 2023 13:39:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C00346B0081; Tue, 2 May 2023 13:39:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id AE8EE6B007E for ; Tue, 2 May 2023 13:39:23 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 3342B12061F for ; Tue, 2 May 2023 17:38:45 +0000 (UTC) X-FDA: 80746025010.18.DD441B5 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf21.hostedemail.com (Postfix) with ESMTP id 9FCA91C0A02 for ; Tue, 2 May 2023 11:21:18 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=xQ6JaecB; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=FquHuOLl; dmarc=none; spf=pass (imf21.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1683026502; a=rsa-sha256; cv=none; b=IsLmP/7vmAy9RTJF4hoCfct/rpF0cvS7Z8TTg9k4obb/wWereDHvyFriTmlYOpIyCbCUhJ Qg109LlNxUBrrlVWJMmFO9Sex9x2fl1/Ytvdj6Cgybg+oIzvGIvGWUdXM/o+5EoFLOVskL PLspXoQXs5BikPXVOa4MLc0Z533Jb4U= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=xQ6JaecB; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=FquHuOLl; dmarc=none; spf=pass (imf21.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1683026502; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=EQGFmprAkf6SOGmZcALNchoLIXzx1I6PSxS66a6jet8=; b=cAGRpN6Z3Cpkcmd+7BiBClTIMXFZXXaZaKoGqhAmZ8i1d8w4p1Bsuot2gLsRbj+Jnmxm0+ gpd8ZIzJjiUY727Zkz5zLtmjHmDEuWlsU5bX0hSbMU4UCF7zZEXECUcI/DNpvTY69w/SGr 0r6KVQtQlnqyUahjfNJb4MmshpjRfAc= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 639BD1F8BE; Tue, 2 May 2023 10:00:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1683021648; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EQGFmprAkf6SOGmZcALNchoLIXzx1I6PSxS66a6jet8=; b=xQ6JaecBwap2jvpIJ31SWlM85SFeS5pVbSmJrTo8OcH8F+BJl7Bn+3GZHGG4pRq3YgMFK7 UTSSsOlEhV5ox5haOFuEl/z9ln+zEQ49zYyjI0uz11RCqGbHwtULOI+FNLc+VdR6ZC9bTg /5k3CGJ3kuqBHRJ+CFo/uavxNGinkOQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1683021648; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EQGFmprAkf6SOGmZcALNchoLIXzx1I6PSxS66a6jet8=; b=FquHuOLlZRQgEkHms/NYY7NkRXmeTQlbefmtFXMHofFnlEWcLdee1WSLeDp4v9FRmyYbwh GUYS/XhGVKDhFeDw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 4681C139C3; Tue, 2 May 2023 10:00:48 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id fqmEEFDfUGTlZwAAMHmgww (envelope-from ); Tue, 02 May 2023 10:00:48 +0000 Message-ID: Date: Tue, 2 May 2023 12:00:48 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.1 Subject: Re: [PATCH 1/1] mm: change per-VMA lock statistics to be disabled by default Content-Language: en-US To: Suren Baghdasaryan , akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, lstoakes@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com References: <20230428173533.18158-1-surenb@google.com> From: Vlastimil Babka In-Reply-To: <20230428173533.18158-1-surenb@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 9FCA91C0A02 X-Stat-Signature: hhbdxg9bt6idbr65jrizp457rmiojstr X-Rspam-User: X-HE-Tag: 1683026478-952224 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 4/28/23 19:35, Suren Baghdasaryan wrote: > Change CONFIG_PER_VMA_LOCK_STATS to be disabled by default, as most > users don't need it. Add configuration help to clarify its usage. > > Fixes: 52f238653e45 ("mm: introduce per-VMA lock statistics") > Suggested-by: Linus Torvalds > Signed-off-by: Suren Baghdasaryan Acked-by: Vlastimil Babka > --- > mm/Kconfig.debug | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 6dae63b46368..a925415b4d10 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -274,6 +274,12 @@ config DEBUG_KMEMLEAK_AUTO_SCAN > config PER_VMA_LOCK_STATS > bool "Statistics for per-vma locks" > depends on PER_VMA_LOCK > - default y > help > - Statistics for per-vma locks. > + Say Y here to enable success, retry and failure counters of page > + faults handled under protection of per-vma locks. When enabled, the > + counters are exposed in /proc/vmstat. This information is useful for > + kernel developers to evaluate effectiveness of per-vma locks and to > + identify pathological cases. Counting these events introduces a small > + overhead in the page fault path. > + > + If in doubt, say N.