Re: [PATCH v4 1/3] x86/sgx: Report SGX memory in /sys/devices/system/node/node*/meminfo
From: Greg Kroah-Hartman
Date: Fri Sep 10 2021 - 11:11:09 EST
On Fri, Sep 10, 2021 at 06:02:59PM +0300, Jarkko Sakkinen wrote:
> On Fri, 2021-09-10 at 16:05 +0200, Greg Kroah-Hartman wrote:
> > On Fri, Sep 10, 2021 at 04:17:44PM +0300, Jarkko Sakkinen wrote:
> > > On Fri, 2021-09-10 at 08:51 +0200, Greg Kroah-Hartman wrote:
> > > > On Fri, Sep 10, 2021 at 03:17:24AM +0300, Jarkko Sakkinen wrote:
> > > > > The amount of SGX memory on the system is determined by the BIOS and it
> > > > > varies wildly between systems. It can be from dozens of MB's on desktops
> > > > > or VM's, up to many GB's on servers. Just like for regular memory, it is
> > > > > sometimes useful to know the amount of usable SGX memory in the system.
> > > > >
> > > > > Add SGX_MemTotal field to /sys/devices/system/node/node*/meminfo,
> > > > > showing the total SGX memory in each NUMA node. The total memory for
> > > > > each NUMA node is calculated by adding the sizes of contained EPC
> > > > > sections together.
> > > > >
> > > > > Introduce arch_node_read_meminfo(), which can optionally be rewritten by
> > > > > the arch code, and rewrite it for x86 so it prints SGX_MemTotal.
> > > > >
> > > > > Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
> > > > > ---
> > > > > v4:
> > > > > * A new patch.
> > > > > arch/x86/kernel/cpu/sgx/main.c | 14 ++++++++++++++
> > > > > arch/x86/kernel/cpu/sgx/sgx.h | 6 ++++++
> > > > > drivers/base/node.c | 10 +++++++++-
> > > > > 3 files changed, 29 insertions(+), 1 deletion(-)
> > > >
> > > > Where is the Documentation/ABI/ update for this new sysfs file?
> > >
> > > It's has been existed for a long time, e.g.
> > >
> > > cat /sys/devices/system/node/node0/meminfo
> > > Node 0 MemTotal: 32706792 kB
> > > Node 0 MemFree: 5382988 kB
> > > Node 0 MemUsed: 27323804 kB
> > > Node 0 SwapCached: 8 kB
> > > Node 0 Active: 3640612 kB
> > > Node 0 Inactive: 21757684 kB
> > > Node 0 Active(anon): 2833772 kB
> > > Node 0 Inactive(anon): 14392 kB
> > > Node 0 Active(file): 806840 kB
> > > Node 0 Inactive(file): 21743292 kB
> > > Node 0 Unevictable: 80640 kB
> > > Node 0 Mlocked: 80640 kB
> > > Node 0 Dirty: 36 kB
> > > Node 0 Writeback: 0 kB
> > > Node 0 FilePages: 22833124 kB
> > > Node 0 Mapped: 1112832 kB
> > > Node 0 AnonPages: 2645812 kB
> > > Node 0 Shmem: 282984 kB
> > > Node 0 KernelStack: 18544 kB
> > > Node 0 PageTables: 46704 kB
> > > Node 0 NFS_Unstable: 0 kB
> > > Node 0 Bounce: 0 kB
> > > Node 0 WritebackTmp: 0 kB
> > > Node 0 KReclaimable: 1311812 kB
> > > Node 0 Slab: 1542220 kB
> > > Node 0 SReclaimable: 1311812 kB
> > > Node 0 SUnreclaim: 230408 kB
> > > Node 0 AnonHugePages: 0 kB
> > > Node 0 ShmemHugePages: 0 kB
> > > Node 0 ShmemPmdMapped: 0 kB
> > > Node 0 FileHugePages: 0 kB
> > > Node 0 FilePmdMapped: 0 kB
> > > Node 0 HugePages_Total: 0
> > > Node 0 HugePages_Free: 0
> > > Node 0 HugePages_Surp: 0
> This was something also spinned my head a bit, i.e. why hugepages fields
> are not aligned correctly.
> > >
> > > This file is undocumented but the fields seem to reflect what is in
> > > /proc/meminfo, so I added additional patch for documentation:
> > >
> > > https://lore.kernel.org/linux-sgx/20210910001726.811497-3-jarkko@xxxxxxxxxx/
> > >
> > > I have no idea why things are how they are. I'm just merely trying to follow
> > > the existing patterns. I'm also fully aware of the defacto sysfs pattern, i.e.
> > > one value per file.
> > Then please do not add anything else to this nightmare of a mess.
> There is already /sys/devices/system/node/node0/hugepages/.
> It has alike data to the contents of meminfo:
> [I'm wondering tho, how the fields in meminfo are supposed to be interpreted,
> given that there are two types of huge pages, but let's just ignore that
> for the moment.]
> Following this pattern, I'd perhaps go and create (and document):
> which would have the size in bytes.
If it is one-value-per-file, that's fine with me.