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Date: Mon, 15 Sep 2014 19:50:27 +0100 From: Will Deacon <will.deacon@....com> To: Russell King - ARM Linux <linux@....linux.org.uk> Cc: "Wang, Yalin" <Yalin.Wang@...ymobile.com>, "'linux-kernel@...r.kernel.org'" <linux-kernel@...r.kernel.org>, "'linux-arm-kernel@...ts.infradead.org'" <linux-arm-kernel@...ts.infradead.org>, "'linux-mm@...ck.org'" <linux-mm@...ck.org> Subject: Re: [PATCH] arm64:free_initrd_mem should also free the memblock On Mon, Sep 15, 2014 at 07:40:23PM +0100, Russell King - ARM Linux wrote: > On Mon, Sep 15, 2014 at 07:33:34PM +0100, Will Deacon wrote: > > On Fri, Sep 12, 2014 at 11:17:18AM +0100, Wang, Yalin wrote: > > > this patch fix the memblock statics for memblock > > > in file /sys/kernel/debug/memblock/reserved > > > if we don't call memblock_free the initrd will still > > > be marked as reserved, even they are freed. > > > > > > Signed-off-by: Yalin Wang <yalin.wang@...ymobile.com> > > > --- > > > arch/arm64/mm/init.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > > > index 5472c24..34605c8 100644 > > > --- a/arch/arm64/mm/init.c > > > +++ b/arch/arm64/mm/init.c > > > @@ -334,8 +334,10 @@ static int keep_initrd; > > > > > > void free_initrd_mem(unsigned long start, unsigned long end) > > > { > > > - if (!keep_initrd) > > > + if (!keep_initrd) { > > > free_reserved_area((void *)start, (void *)end, 0, "initrd"); > > > + memblock_free(__pa(start), end - start); > > > + } > > > > I don't think it makes any technical difference, but doing the memblock_free > > before the free_reserved_area makes more sense to me. > > A better question is... should we even be doing this. The memblock > information is used as a method to bring up the kernel and provide > early allocation. Once the memory is handed over from memblock to > the normal kernel page allocators, we no longer care what happens to > memblock. > > There is no need to free the initrd memory back into memblock. In > fact, seeing the initrd location in /sys/kernel/debug/memblock/reserved > can be useful debug information in itself. That's a fair point. Yang: do you have a specific use-case in mind for this? I wondered if it might interact with our pfn_valid implementation, which uses memblock_is_memory, however memblock_free only deals with the reserved regions, so I now I can't see why this change is required either. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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