| Message ID | 1568618488-19055-1-git-send-email-rppt@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: use generic free_initrd_mem() | expand |
On 9/16/19 8:21 AM, Mike Rapoport wrote: > From: Mike Rapoport <rppt@linux.ibm.com> > > arm64 calls memblock_free() for the initrd area in its implementation of > free_initrd_mem(), but this call has no actual effect that late in the boot > process. By the time initrd is freed, all the reserved memory is managed by > the page allocator and the memblock.reserved is unused, so there is no > point to update it. > People like to use memblock for keeping track of memory even if it has no actual effect. We made this change explicitly (see 05c58752f9dc ("arm64: To remove initrd reserved area entry from memblock") That said, moving to the generic APIs would be nice. Maybe we can find another place to update the accounting? > Without the memblock_free() call the only difference between arm64 and the > generic versions of free_initrd_mem() is the memory poisoning. Switching > arm64 to the generic version will enable the poisoning. > > Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> > --- > > I've boot tested it on qemu and I've checked that kexec works. > > arch/arm64/mm/init.c | 8 -------- > 1 file changed, 8 deletions(-) > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index f3c7952..8ad2934 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -567,14 +567,6 @@ void free_initmem(void) > unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin)); > } > > -#ifdef CONFIG_BLK_DEV_INITRD > -void __init free_initrd_mem(unsigned long start, unsigned long end) > -{ > - free_reserved_area((void *)start, (void *)end, 0, "initrd"); > - memblock_free(__virt_to_phys(start), end - start); > -} > -#endif > - > /* > * Dump out memory limit information on panic. > */ >
(added linux-arch) On Mon, Sep 16, 2019 at 08:23:29AM -0400, Laura Abbott wrote: > On 9/16/19 8:21 AM, Mike Rapoport wrote: > >From: Mike Rapoport <rppt@linux.ibm.com> > > > >arm64 calls memblock_free() for the initrd area in its implementation of > >free_initrd_mem(), but this call has no actual effect that late in the boot > >process. By the time initrd is freed, all the reserved memory is managed by > >the page allocator and the memblock.reserved is unused, so there is no > >point to update it. > > > > People like to use memblock for keeping track of memory even if it has no > actual effect. We made this change explicitly (see 05c58752f9dc ("arm64: To remove > initrd reserved area entry from memblock") That said, moving to the generic > APIs would be nice. Maybe we can find another place to update the accounting? Any other place in arch/arm64 would make it messy because it would have to duplicate keepinitrd logic. We could put the memblock_free() in the generic free_initrd_mem() with something like: diff --git a/init/initramfs.c b/init/initramfs.c index c47dad0..403c6a0 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -531,6 +531,10 @@ void __weak free_initrd_mem(unsigned long start, unsigned long end) { free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM, "initrd"); + +#ifdef CONFIG_ARCH_KEEP_MEMBLOCK + memblock_free(__virt_to_phys(start), end - start); +#endif } #ifdef CONFIG_KEXEC_CORE Then powerpc and s390 folks will also be able to track the initrd memory :) > >Without the memblock_free() call the only difference between arm64 and the > >generic versions of free_initrd_mem() is the memory poisoning. Switching > >arm64 to the generic version will enable the poisoning. > > > >Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> > >--- > > > >I've boot tested it on qemu and I've checked that kexec works. > > > > arch/arm64/mm/init.c | 8 -------- > > 1 file changed, 8 deletions(-) > > > >diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > >index f3c7952..8ad2934 100644 > >--- a/arch/arm64/mm/init.c > >+++ b/arch/arm64/mm/init.c > >@@ -567,14 +567,6 @@ void free_initmem(void) > > unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin)); > > } > >-#ifdef CONFIG_BLK_DEV_INITRD > >-void __init free_initrd_mem(unsigned long start, unsigned long end) > >-{ > >- free_reserved_area((void *)start, (void *)end, 0, "initrd"); > >- memblock_free(__virt_to_phys(start), end - start); > >-} > >-#endif > >- > > /* > > * Dump out memory limit information on panic. > > */ > > >
On 09/16/2019 07:25 PM, Mike Rapoport wrote: > (added linux-arch) > > On Mon, Sep 16, 2019 at 08:23:29AM -0400, Laura Abbott wrote: >> On 9/16/19 8:21 AM, Mike Rapoport wrote: >>> From: Mike Rapoport <rppt@linux.ibm.com> >>> >>> arm64 calls memblock_free() for the initrd area in its implementation of >>> free_initrd_mem(), but this call has no actual effect that late in the boot >>> process. By the time initrd is freed, all the reserved memory is managed by >>> the page allocator and the memblock.reserved is unused, so there is no >>> point to update it. >>> >> >> People like to use memblock for keeping track of memory even if it has no >> actual effect. We made this change explicitly (see 05c58752f9dc ("arm64: To remove >> initrd reserved area entry from memblock") That said, moving to the generic >> APIs would be nice. Maybe we can find another place to update the accounting? > > Any other place in arch/arm64 would make it messy because it would have to > duplicate keepinitrd logic. > > We could put the memblock_free() in the generic free_initrd_mem() with > something like: > > diff --git a/init/initramfs.c b/init/initramfs.c > index c47dad0..403c6a0 100644 > --- a/init/initramfs.c > +++ b/init/initramfs.c > @@ -531,6 +531,10 @@ void __weak free_initrd_mem(unsigned long start, > unsigned long end) > { > free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM, > "initrd"); > + > +#ifdef CONFIG_ARCH_KEEP_MEMBLOCK > + memblock_free(__virt_to_phys(start), end - start); > +#endif > } This makes sense. > > #ifdef CONFIG_KEXEC_CORE > > > Then powerpc and s390 folks will also be able to track the initrd memory :) Sure. > >>> Without the memblock_free() call the only difference between arm64 and the >>> generic versions of free_initrd_mem() is the memory poisoning. Switching >>> arm64 to the generic version will enable the poisoning. >>> >>> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> >>> --- >>> >>> I've boot tested it on qemu and I've checked that kexec works. >>> >>> arch/arm64/mm/init.c | 8 -------- >>> 1 file changed, 8 deletions(-) >>> >>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c >>> index f3c7952..8ad2934 100644 >>> --- a/arch/arm64/mm/init.c >>> +++ b/arch/arm64/mm/init.c >>> @@ -567,14 +567,6 @@ void free_initmem(void) >>> unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin)); >>> } >>> -#ifdef CONFIG_BLK_DEV_INITRD >>> -void __init free_initrd_mem(unsigned long start, unsigned long end) >>> -{ >>> - free_reserved_area((void *)start, (void *)end, 0, "initrd"); >>> - memblock_free(__virt_to_phys(start), end - start); >>> -} >>> -#endif >>> - >>> /* >>> * Dump out memory limit information on panic. >>> */ >>> >> >
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index f3c7952..8ad2934 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -567,14 +567,6 @@ void free_initmem(void) unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin)); } -#ifdef CONFIG_BLK_DEV_INITRD -void __init free_initrd_mem(unsigned long start, unsigned long end) -{ - free_reserved_area((void *)start, (void *)end, 0, "initrd"); - memblock_free(__virt_to_phys(start), end - start); -} -#endif - /* * Dump out memory limit information on panic. */