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c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762517203; 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; bh=9Z9OqNev9/6JMFESBK25MmK6tzbam6/1o5mL0L9/6tQ=; b=uqH4rDoPgRb/DZYg9wEjXvu6sYXpTWa+PBWwhMrzAQd6dVmOhPtmCPbpsWIrJy8eI9IXuO MjqJLqxxa5ljDwmGelM5ToVomtzoIXg7mmhGbuAy+xqYNQZHY6gp+RmH9hKWcw77RhATYQ Z8U362W++7JRk/hFcuulMFzf3xTiqU0= Received: by verein.lst.de (Postfix, from userid 2407) id 101D4227AAE; Fri, 7 Nov 2025 13:06:38 +0100 (CET) Date: Fri, 7 Nov 2025 13:06:37 +0100 From: Christoph Hellwig To: Eric Biggers Cc: Christoph Hellwig , Jens Axboe , Vlastimil Babka , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 3/9] mempool: add mempool_{alloc,free}_bulk Message-ID: <20251107120637.GC30551@lst.de> References: <20251031093517.1603379-1-hch@lst.de> <20251031093517.1603379-4-hch@lst.de> <20251107035207.GA47797@sol> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251107035207.GA47797@sol> User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 0140D40012 X-Stat-Signature: mgokyqs7juft8knonhuqk6fm4fyfb4tx X-HE-Tag: 1762517202-744514 X-HE-Meta: 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 jF10p+a6 JwmL/2Zh9udvdu4TUGeP34QOy5U2TzZGTFe1YtED9pAgVMFQnsGROqLsnHk1F6NNFBmy+ePfS+xWyWT78uM+j4tb+ybZQB5gAyRoB9ob0lVECRj++r9QsvuQAxZlQ9NVfSvoVblGStfrijqc= 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: On Thu, Nov 06, 2025 at 07:52:07PM -0800, Eric Biggers wrote: > > +int mempool_alloc_bulk_noprof(struct mempool *pool, void **elem, > > + unsigned int count, gfp_t gfp_mask, unsigned long caller_ip) > > What exactly is the behavior on partial failures? Is the return value 0 > or is it -ENOMEM, and is the array restored to its original state or > might some elements have been allocated? Right now it frees everything. But as per the discussion with Vlastimil I'll move to not allowing non-blocking allocations for multiple elements, at which point the failure case just can't happen and that is sorted out. > > +} > > EXPORT_SYMBOL(mempool_alloc_noprof); > > How much overhead does this add to mempool_alloc(), which will continue > to be the common case? I wonder if it would be worthwhile to > force-inline the bulk allocation function into it, so that it will get > generate about the same code as before. It's about 10 extra instructions looking at my profiles. So I don't think it matters, but if the maintainers prefer force inlining I can do that.