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bh=Lx9tonMV0p2LmGJzOUVmxlBkhvvyPY8HKeuAJPQh4ks=; b=lK5IhehpmssMnTKxdBPOWJ6FwenHO4AUxX3t+ItSvSa8aQd1liz32rxnFfsuF4P4mEVXmm x5N5wbY5N+SOGshCLSfORkSdYDJbvlOiTfwb0Q+su98rU52Qwz5S/b/9EF680lLKga9eTF uE2CvXGmtfCRkv5pLJThqB1Ki728rMA= Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id E026113874; Thu, 18 Jan 2024 09:04:30 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id PpbYNZ7pqGXBMQAAD6G6ig (envelope-from ); Thu, 18 Jan 2024 09:04:30 +0000 Date: Thu, 18 Jan 2024 10:04:29 +0100 From: Michal =?utf-8?Q?Koutn=C3=BD?= To: Josh Poimboeuf Cc: Linus Torvalds , Jeff Layton , Chuck Lever , Shakeel Butt , Roman Gushchin , Johannes Weiner , Michal Hocko , linux-kernel@vger.kernel.org, Jens Axboe , Tejun Heo , Vasily Averin , Waiman Long , Muchun Song , Jiri Kosina , cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH RFC 4/4] mitigations: Add flock cache accounting to 'mitigations=off' Message-ID: References: <3e803d5aee5dd1f4c738f0de1e839e6cfcb9dc41.1705507931.git.jpoimboe@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="u4b4gqso4ihknobk" Content-Disposition: inline In-Reply-To: <3e803d5aee5dd1f4c738f0de1e839e6cfcb9dc41.1705507931.git.jpoimboe@kernel.org> Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.com header.s=susede1 header.b=lK5Ihehp X-Spamd-Result: default: False [-4.08 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_DKIM_ALLOW(-0.20)[suse.com:s=susede1]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.20)[multipart/signed,text/plain]; DWL_DNSWL_MED(-2.00)[suse.com:dkim]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; DKIM_TRACE(0.00)[suse.com:+]; MX_GOOD(-0.01)[]; RCPT_COUNT_TWELVE(0.00)[17]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:dkim]; SIGNED_PGP(-2.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; MID_RHS_NOT_FQDN(0.50)[]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-0.17)[70.01%] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 4FA5922049 X-Spam-Level: X-Spam-Score: -4.08 X-Spam-Flag: NO --u4b4gqso4ihknobk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Jan 17, 2024 at 08:14:46AM -0800, Josh Poimboeuf wrote: > Allow flock cache accounting to be disabled with 'mitigations=off', as > it fits the profile for that option: trusted user space combined with a > performance-impacting mitigation. Note that some other kernel objects that don't have any other tight limit are already charged too (but their charging likely did not stand out in any performance regression tests). In the situation you describe, users can already pass `cgroup.memory=nokmem` and get rid of charging overhead in general. IOW, if flock objects are charged, there already is a boot option to turn off such behavior. Regards, Michal --u4b4gqso4ihknobk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQQpEWyjXuwGT2dDBqAGvrMr/1gcjgUCZajpkQAKCRAGvrMr/1gc jnI1AQCbThmyZZHc0yb1sSU87kRYGU6A+8Qm5wtthTdtlNoPuwEAnOxavnxMkLvy VhsoAek+ajhMUjJp7v03BI1OEx2X/AA= =LaB0 -----END PGP SIGNATURE----- --u4b4gqso4ihknobk--