From mboxrd@z Thu Jan 1 00:00:00 1970 From: Con Kolivas Subject: Re: [PATCH] mm: Implement Swap Prefetching v22 Date: Fri, 10 Feb 2006 11:08:46 +1100 References: <200602092339.49719.kernel@kolivas.org> <43EB43B9.5040001@yahoo.com.au> <17387.33855.858274.530175@gargle.gargle.HOWL> In-Reply-To: <17387.33855.858274.530175@gargle.gargle.HOWL> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200602101108.47614.kernel@kolivas.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Nikita Danilov Cc: Nick Piggin , linux-kernel@vger.kernel.org, Andrew Morton , ck list , linux-mm@kvack.org, Nick Piggin , Paul Jackson List-ID: On Friday 10 February 2006 05:04, Nikita Danilov wrote: > Nick Piggin writes: > > [...] > > > > +/* > > > + * We check to see no part of the vm is busy. If it is this will > > > interrupt + * trickle_swap and wait another PREFETCH_DELAY. > > > Purposefully racy. + */ > > > +inline void delay_swap_prefetch(void) > > > +{ > > > + __set_bit(0, &swapped.busy); > > > +} > > > + > > > > Test this first so you don't bounce the cacheline around in page > > reclaim too much. > > Shouldn't we have special macros/inlines for this? Like, e.g., > > static inline void __set_bit_weak(int nr, volatile unsigned long * addr) > { > if (!__test_bit(nr, addr)) > __set_bit(nr, addr); > } > > ? These test-then-set sequences start to proliferate throughout the code. Maybe. There isn't actually a non-atomic __test_bit anyway, only a test_bit. The non-atomic __test_and_set_bit already exists, but that sets the bit regardless of what the bit was as far as I can tell. Cheers, Con -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org