From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (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 167762DAF8C for ; Tue, 29 Apr 2025 23:04:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745967902; cv=none; b=gi8A/Y7Ijp0Md5IwoRosGv8xHu6/Bq9smqwKrwZAS041Hv1pJ9Ckpe8FzjhE3JDKepqFxxOP7OtdDW0uqU3o1egSlpAor9MHq/u9pch/zxVPQ87ksNKYgBFiIbUDnR6Lwfzb+n8+YsQCD6uwXKYsxkX17KAB23uz8cLD+TAzKqs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745967902; c=relaxed/simple; bh=kNpHfcQPDo+Dwyzi8dvG+NXgW53MJezi2FuhTG11jW8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FA9ubyTmvX2CM2cTmmhQtXVVfZgb0aPRpPaN70llMq5AUYEg4VPVvFqtehNJhSdxNewpu1lDKAGCuZq24MbXrueZWajZpESquJV38K+VJYy7diCH9tzyYCrYOfbsQpNPVaixI3b2eMoEX+Cx+ACXd09fzqjo3ddCVjkGP+0mZ4U= 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=CJCd6vVv; arc=none smtp.client-ip=95.215.58.173 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="CJCd6vVv" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745967896; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nbvCkVhHHtDcKqUC2DWDg/6KEw2udjRnrOYkfHNgmcQ=; b=CJCd6vVvXZmXfHc16o6jHtkjQhqPmzqlTLuls9wv21E9hSk5pLIRwuOpgLHAUdkr/xPWcd YcTswv8gGCM1Yzmbh01N3laHDwhpOTiw6sGCXQu1zWaXvJcc+GAOhT5P6u74GEev34ey9n DoqFyl9jm8SW2DIYAreOcNHzQRvsdqI= From: Shakeel Butt To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Sebastian Andrzej Siewior , Vlastimil Babka , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: [PATCH 1/4] memcg: simplify consume_stock Date: Tue, 29 Apr 2025 16:04:25 -0700 Message-ID: <20250429230428.1935619-2-shakeel.butt@linux.dev> In-Reply-To: <20250429230428.1935619-1-shakeel.butt@linux.dev> References: <20250429230428.1935619-1-shakeel.butt@linux.dev> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT The consume_stock() does not need to check gfp_mask for spinning and can simply trylock the local lock to decide to proceed or fail. No need to spin at all for local lock. Signed-off-by: Shakeel Butt --- mm/memcontrol.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 650fe4314c39..40d0838d88bc 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1804,16 +1804,14 @@ static bool obj_stock_flush_required(struct memcg_stock_pcp *stock, * consume_stock: Try to consume stocked charge on this cpu. * @memcg: memcg to consume from. * @nr_pages: how many pages to charge. - * @gfp_mask: allocation mask. * - * The charges will only happen if @memcg matches the current cpu's memcg - * stock, and at least @nr_pages are available in that stock. Failure to - * service an allocation will refill the stock. + * Consume the cached charge if enough nr_pages are present otherwise return + * failure. Also return failure for charge request larger than + * MEMCG_CHARGE_BATCH or if the local lock is already taken. * * returns true if successful, false otherwise. */ -static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages, - gfp_t gfp_mask) +static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { struct memcg_stock_pcp *stock; uint8_t stock_pages; @@ -1821,12 +1819,8 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages, bool ret = false; int i; - if (nr_pages > MEMCG_CHARGE_BATCH) - return ret; - - if (gfpflags_allow_spinning(gfp_mask)) - local_lock_irqsave(&memcg_stock.stock_lock, flags); - else if (!local_trylock_irqsave(&memcg_stock.stock_lock, flags)) + if (nr_pages > MEMCG_CHARGE_BATCH || + !local_trylock_irqsave(&memcg_stock.stock_lock, flags)) return ret; stock = this_cpu_ptr(&memcg_stock); @@ -2329,7 +2323,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, unsigned long pflags; retry: - if (consume_stock(memcg, nr_pages, gfp_mask)) + if (consume_stock(memcg, nr_pages)) return 0; if (!gfpflags_allow_spinning(gfp_mask)) -- 2.47.1