| Message ID | c5f96b483158871ff65377884955fb0106e43951.1602899443.git.sudaraja@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/memory_hotplug, arm64: allow certain bootmem sections to be offlinable | expand |
> Am 17.10.2020 um 04:03 schrieb Sudarshan Rajagopalan <sudaraja@codeaurora.org>: > > On receiving the MEM_GOING_OFFLINE notification, we disallow offlining of > any boot memory by checking if section_early or not. With the introduction > of SECTION_MARK_HOTPLUGGABLE, allow boot mem sections that are marked as > hotpluggable with this bit set to be offlined and removed. This now allows > certain boot mem sections to be offlined. > The check (notifier) is in arm64 code. I don‘t see why you cannot make such decisions completely in arm64 code? Why would you have to mark sections? Also, I think I am missing from *where* the code that marks sections removable is even called? Who makes such decisions? This feels wrong. > Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Anshuman Khandual <anshuman.khandual@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Gavin Shan <gshan@redhat.com> > Cc: Logan Gunthorpe <logang@deltatee.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Steven Price <steven.price@arm.com> > Cc: Suren Baghdasaryan <surenb@google.com> > --- > arch/arm64/mm/mmu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 75df62fea1b6..fb8878698672 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1487,7 +1487,7 @@ static int prevent_bootmem_remove_notifier(struct notifier_block *nb, > > for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { > ms = __pfn_to_section(pfn); > - if (early_section(ms)) > + if (early_section(ms) && !removable_section(ms)) > return NOTIFY_BAD; > } > return NOTIFY_OK; > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project >
On 10/17/2020 01:04 PM, David Hildenbrand wrote: > >> Am 17.10.2020 um 04:03 schrieb Sudarshan Rajagopalan <sudaraja@codeaurora.org>: >> >> On receiving the MEM_GOING_OFFLINE notification, we disallow offlining of >> any boot memory by checking if section_early or not. With the introduction >> of SECTION_MARK_HOTPLUGGABLE, allow boot mem sections that are marked as >> hotpluggable with this bit set to be offlined and removed. This now allows >> certain boot mem sections to be offlined. >> > > The check (notifier) is in arm64 code. I don‘t see why you cannot make such decisions completely in arm64 code? Why would you have to mark sections? > > Also, I think I am missing from *where* the code that marks sections removable is even called? Who makes such decisions? From the previous patch. +EXPORT_SYMBOL_GPL(mark_memory_hotpluggable); > > This feels wrong. > >> Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Will Deacon <will@kernel.org> >> Cc: Anshuman Khandual <anshuman.khandual@arm.com> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Gavin Shan <gshan@redhat.com> >> Cc: Logan Gunthorpe <logang@deltatee.com> >> Cc: David Hildenbrand <david@redhat.com> >> Cc: Andrew Morton <akpm@linux-foundation.org> >> Cc: Steven Price <steven.price@arm.com> >> Cc: Suren Baghdasaryan <surenb@google.com> >> --- >> arch/arm64/mm/mmu.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 75df62fea1b6..fb8878698672 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1487,7 +1487,7 @@ static int prevent_bootmem_remove_notifier(struct notifier_block *nb, >> >> for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { >> ms = __pfn_to_section(pfn); >> - if (early_section(ms)) >> + if (early_section(ms) && !removable_section(ms)) Till challenges related to boot memory removal on arm64 platform get resolved, no portion of boot memory can be offlined. Let alone via a driver making such decisions. >> return NOTIFY_BAD; >> } >> return NOTIFY_OK; >> -- >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, >> a Linux Foundation Collaborative Project >> > >
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 75df62fea1b6..fb8878698672 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1487,7 +1487,7 @@ static int prevent_bootmem_remove_notifier(struct notifier_block *nb, for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { ms = __pfn_to_section(pfn); - if (early_section(ms)) + if (early_section(ms) && !removable_section(ms)) return NOTIFY_BAD; } return NOTIFY_OK;
On receiving the MEM_GOING_OFFLINE notification, we disallow offlining of any boot memory by checking if section_early or not. With the introduction of SECTION_MARK_HOTPLUGGABLE, allow boot mem sections that are marked as hotpluggable with this bit set to be offlined and removed. This now allows certain boot mem sections to be offlined. Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Gavin Shan <gshan@redhat.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: David Hildenbrand <david@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> --- arch/arm64/mm/mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)