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Thu, 30 Sep 2021 21:10:58 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 6nSdNuInVmFPQwAAMHmgww (envelope-from ); Thu, 30 Sep 2021 21:10:58 +0000 Subject: Re: [PATCH] xfs: use kmem_cache_free() for kmem_cache objects To: Rustam Kovhaev Cc: Dave Chinner , djwong@kernel.org, linux-xfs@vger.kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, Al Viro References: <20210929212347.1139666-1-rkovhaev@gmail.com> <20210930044202.GP2361455@dread.disaster.area> <17f537b3-e2eb-5d0a-1465-20f3d3c960e2@suse.cz> From: Vlastimil Babka Message-ID: Date: Thu, 30 Sep 2021 23:10:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: AFFC8D000453 X-Stat-Signature: 7fgjrdritdjpwjd7jgopb337ggxienny Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=sIdcON51; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=txE+MXYP; dmarc=none; spf=pass (imf20.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.28 as permitted sender) smtp.mailfrom=vbabka@suse.cz X-HE-Tag: 1633036260-383007 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 9/30/21 8:48 PM, Rustam Kovhaev wrote: > On Thu, Sep 30, 2021 at 10:13:40AM +0200, Vlastimil Babka wrote: >> >> I think it's fair if something like XFS (not meant for tiny systems AFAIK?) >> excludes SLOB (meant for tiny systems). Clearly nobody tried to use these >> two together last 5 years anyway. > > +1 for adding Kconfig option, it seems like some things are not meant to > be together. But if we patch SLOB, we won't need it. >> Maybe we could also just add the 4 bytes to all SLOB objects, declare >> kfree() is always fine and be done with it. Yes, it will make SLOB footprint >> somewhat less tiny, but even whan we added kmalloc power of two alignment >> guarantees, the impact on SLOB was negligible. > > I'll send a patch to add a 4-byte header for kmem_cache_alloc() > allocations. Thanks. Please report in the changelog slab usage from /proc/meminfo before and after patch (at least a snapshot after a full boot). >>> Thoughts? >>> >>> Cheers, >>> >>> Dave. >>> >>