From mboxrd@z Thu Jan 1 00:00:00 1970 From: gmbnomis@gmail.com (Simon Baatz) Date: Thu, 27 Sep 2012 19:35:43 +0200 Subject: [PATCH 2/2] ARM: remove unnecessary flush of anon pages in flush(_kernel)_dcache_page() In-Reply-To: <20120927122327.GA26188@arm.com> References: <1348695659-27603-1-git-send-email-gmbnomis@gmail.com> <1348695659-27603-3-git-send-email-gmbnomis@gmail.com> <20120927122327.GA26188@arm.com> Message-ID: <20120927173543.GA20442@schnuecks.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Catalin, On Thu, Sep 27, 2012 at 01:23:28PM +0100, Catalin Marinas wrote: > On Wed, Sep 26, 2012 at 10:40:59PM +0100, Simon Baatz wrote: > > On non-aliasing VIPT D-caches, there is no need to flush the kernel > > mapping of anon pages in flush_kernel_dcache_page() and > > flush_dcache_page() directly. If the page is mapped as executable > > later, the necessary D/I-cache flush will be done in > > __sync_icache_dcache(). > > > > Signed-off-by: Simon Baatz > > Cc: Catalin Marinas > > Cc: Russell King > > I would suggest you make this patch the first one rather than > introducing __flush_kernel_dcache_page() and subsequently replacing its > code. The reason for this structure is that I did not want to mix the bug fix (which may qualify for stable) with the improvement. If I do the patches the other way around and only the bug fix patch will be picked for stable, flush_dcache_page() and flush_kernel_dcache_page() will have different logic in which cases to flush. We know that the current logic is solid, we don't have much evidence for the logic of the proposed improvement. >>From this point of view, I find the current structure cleaner, but I have no strong opinion about this. If we can't apply that particular patch for stable anyway or you still think it is better the other way around, I can change that of course. - Simon