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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 87D231A0003 X-Stat-Signature: su6npeg3z4jd57qoqmdyesn6gf6rxcu1 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1745967899-245626 X-HE-Meta: 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 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: List-Subscribe: List-Unsubscribe: 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