From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B60322EE8 for ; Wed, 28 Feb 2024 06:44:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709102665; cv=none; b=qWm81U5Q8AsHltyVIvOVB6wmsXxl/Mwm5lyjfyjpUcdGgnkotNSUDmHQUYC/oYvY9LJwXJH3IDlrhmbuiidNCmAXnago6zPx281WKIxheG+TfOu1zUq0n8wa44POMU0oW7CSBXM2h0aQILmPWSSOMeepSTHqrGW9STSJhjRfSYc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709102665; c=relaxed/simple; bh=LCnv3tVxpmAlhvoDB2KmHsp3n+wtnCb16MlPujATOX8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=cs3x1jJj+GuYGIQQy47WrnkoxDU2VBAcpFpqeGXDE3j7k3ZIzTlhyWTIYbKOQlFueccw65kyL/HAFmT5+A/scl5c9JYF/gzkYzJY6I1Bn+NeEVBm3Klf+1Nchb4zlITzLNzDGu2hiseTK8VMYdKqBKalUXgFzvg+Qq9Pvi7UOs4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=uDUJ6vts; arc=none smtp.client-ip=95.215.58.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="uDUJ6vts" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1709102660; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mDw5AbPTFhldWRncX473mReQMJoUYqgYBgyYIvyTquk=; b=uDUJ6vtsCZLEtFibLEIP8BQ26/lnZ5LbvVahVBolUFrnAoq2E/C2cplUVj5eF5ZnjAJfKp 99KP8bMjTsc2FlUIdSumDFB1BhlM6BfC+5oeDdPuCeELrB3IzPBaM+mQWU+KAZs2xAnYMk WJ2ee2mPti3LBzWs0QPe8JPf7z60wxc= Date: Wed, 28 Feb 2024 14:44:13 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mm/zsmalloc: don't hold locks of all pages when free_zspage() Content-Language: en-US To: Sergey Senozhatsky Cc: yosryahmed@google.com, hannes@cmpxchg.org, nphamcs@gmail.com, Andrew Morton , Minchan Kim , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240226-zsmalloc-zspage-rcu-v1-0-456b0ef1a89d@bytedance.com> <20240226-zsmalloc-zspage-rcu-v1-1-456b0ef1a89d@bytedance.com> <20240228060113.GJ11972@google.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: <20240228060113.GJ11972@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2024/2/28 14:01, Sergey Senozhatsky wrote: > On (24/02/27 03:02), Chengming Zhou wrote: >> static void __free_zspage(struct zs_pool *pool, struct size_class *class, >> struct zspage *zspage) >> { >> @@ -834,13 +841,12 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class, >> VM_BUG_ON_PAGE(!PageLocked(page), page); > > Who owns page lock here if free_zspage() doesn't trylock_zspage() no longer? Right, it should be removed. > >> next = get_next_page(page); >> reset_page(page); >> - unlock_page(page); >> dec_zone_page_state(page, NR_ZSPAGES); >> put_page(page); >> page = next; >> } while (page != NULL); >> >> - cache_free_zspage(pool, zspage); >> + call_rcu(&zspage->rcu_head, rcu_free_zspage); >> >> class_stat_dec(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage); >> atomic_long_sub(class->pages_per_zspage, &pool->pages_allocated); >> @@ -852,16 +858,6 @@ static void free_zspage(struct zs_pool *pool, struct size_class *class, >> VM_BUG_ON(get_zspage_inuse(zspage)); >> VM_BUG_ON(list_empty(&zspage->list)); >> >> - /* >> - * Since zs_free couldn't be sleepable, this function cannot call >> - * lock_page. The page locks trylock_zspage got will be released >> - * by __free_zspage. >> - */ >> - if (!trylock_zspage(zspage)) { >> - kick_deferred_free(pool); >> - return; >> - } >> - >> remove_zspage(class, zspage); >> __free_zspage(pool, class, zspage); >> }