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dkim=pass header.d=linutronix.de header.s=2020e header.b=dkrS2K0z; spf=pass (imf15.hostedemail.com: domain of tglx@linutronix.de designates 193.142.43.55 as permitted sender) smtp.mailfrom=tglx@linutronix.de; dmarc=pass (policy=none) header.from=linutronix.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1684858216; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1zByDLw4jU19QkZTswmfUVY79YR8HJS8mrQN8c+Tlns=; b=zhOofhXcyIsdcsGhKUkTinEBg0+Sd2yqBYMThC5yKlGsBxSfX2KMPE5CiC0NbR/InR7QCR gxITAqqnwGhidhVZyzQ/o6p7FJvdYKOQT9CuRLjY9m2vXmHr94jY3//YEdEVKZTfhWvqXV GWppezUMNHxu4H71+2uHWkqyFE42ePI= From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1684858214; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1zByDLw4jU19QkZTswmfUVY79YR8HJS8mrQN8c+Tlns=; b=osFyiFDJgQc4PJ+JwuMnPLE1iXhMJ/yZNhUdBf0ivVCRxbiRrgGF3Ot8wdi3Mltxqewahx PCXBEDNWfw3X5N8fMPq67wrHVkSIuKdgZiKuj6rrKZorIkCCHgAWNB9H/ZEVWG6wYyOPUC WQHSix+fpPlR+P9TrQqceKwBRe0hbdTOJ0XnfUBL+UT2qgPkGd+UpwstAO1bStypwV78lF YJeGoW7oJv7WKWiZjMYcBQvWjk7UVZtomLffEsRejbsGFtbhcWqsuBCUmBgpqbnmMlfosX 5WH0LPO9WFzNIR0FVB/8cso/52qh0BzJu8OrQUQLosgjiyvWjvEpT8pQqhjIlw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1684858214; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1zByDLw4jU19QkZTswmfUVY79YR8HJS8mrQN8c+Tlns=; b=dkrS2K0zkf6ucJ8bgutolQWDqPf0rpcLKEB5SanhPM3ST9D7Dgdcyft7jMvPxCycbSUegb lIoWTpRDPlVyb2CQ== To: Christoph Hellwig Cc: linux-mm@kvack.org, Andrew Morton , Christoph Hellwig , Uladzislau Rezki , Lorenzo Stoakes , Peter Zijlstra , Baoquan He Subject: Re: [patch 3/6] mm/vmalloc: Prevent flushing dirty space over and over In-Reply-To: <20230523152717.GC12341@lst.de> References: <20230523135902.517032811@linutronix.de> <20230523140002.690874212@linutronix.de> <20230523152717.GC12341@lst.de> Date: Tue, 23 May 2023 18:10:13 +0200 Message-ID: <87ilcjuize.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: AD969A001E X-Stat-Signature: 3rugfksi816xi7f8hembakrnry17ps4u X-Rspam-User: X-HE-Tag: 1684858216-915939 X-HE-Meta: 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 ilchT/WP dLhGr4ONUwHs/bYZXOxsa0oAqC6nv5n1bUhaLwwfQh+5B61M= 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 Tue, May 23 2023 at 17:27, Christoph Hellwig wrote: > On Tue, May 23, 2023 at 04:02:13PM +0200, Thomas Gleixner wrote: >> vmap blocks which have active mappings cannot be purged. Allocations which >> have been freed are accounted for in vmap_block::dirty_min/max, so that >> they can be detected in _vm_unmap_aliases() as potentially stale TLBs. >> >> If there are several invocations of _vm_unmap_aliases() then each of them >> will flush the dirty range. That's pointless and just increases the >> probability of full TLB flushes. >> >> Avoid that by resetting the flush range after accounting for it. That's >> safe versus other invocations of _vm_unmap_aliases() because this is all >> serialized with vmap_purge_lock. > > Just nitpicking, but isn't vb->lock the actually relevant lock here? > vmap_purge_lock is only taken after the loop. No. The avoid double list iteration change moves the purge lock up before the loop as it needs to protect against a concurrent purge attempt. Thanks, tglx