diff options
author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2018-11-29 12:12:29 -0500 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2018-11-30 03:37:57 -0500 |
commit | 80424b02d42bb22f8ff8839cb93a84ade53b39c0 (patch) | |
tree | 3c846aaef4d718a0c7902a91514cbf5ab2a17429 | |
parent | 5f0b0ecf043a5319e729c11a53bc8294df12dab3 (diff) |
efi: Reduce the amount of memblock reservations for persistent allocations
The current implementation of efi_mem_reserve_persistent() is rather
naive, in the sense that for each invocation, it creates a separate
linked list entry to describe the reservation. Since the linked list
entries themselves need to persist across subsequent kexec reboots,
every reservation created this way results in two memblock_reserve()
calls at the next boot.
On arm64 systems with 100s of CPUs, this may result in a excessive
number of memblock reservations, and needless fragmentation.
So instead, make use of the newly updated struct linux_efi_memreserve
layout to put multiple reservations into a single linked list entry.
This should get rid of the numerous tiny memblock reservations, and
effectively cut the total number of reservations in half on arm64
systems with many CPUs.
[ mingo: build warning fix. ]
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arend van Spriel <arend.vanspriel@broadcom.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Snowberg <eric.snowberg@oracle.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jon Hunter <jonathanh@nvidia.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20181129171230.18699-11-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r-- | drivers/firmware/efi/efi.c | 21 | ||||
-rw-r--r-- | include/linux/efi.h | 3 |
2 files changed, 20 insertions, 4 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 80b11521627a..4c46ff6f2242 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c | |||
@@ -997,8 +997,8 @@ static int __init efi_memreserve_map_root(void) | |||
997 | int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) | 997 | int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) |
998 | { | 998 | { |
999 | struct linux_efi_memreserve *rsv; | 999 | struct linux_efi_memreserve *rsv; |
1000 | int rsvsize = EFI_MEMRESERVE_SIZE(1); | 1000 | unsigned long prsv; |
1001 | int rc; | 1001 | int rc, index; |
1002 | 1002 | ||
1003 | if (efi_memreserve_root == (void *)ULONG_MAX) | 1003 | if (efi_memreserve_root == (void *)ULONG_MAX) |
1004 | return -ENODEV; | 1004 | return -ENODEV; |
@@ -1009,11 +1009,24 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) | |||
1009 | return rc; | 1009 | return rc; |
1010 | } | 1010 | } |
1011 | 1011 | ||
1012 | rsv = kmalloc(rsvsize, GFP_ATOMIC); | 1012 | /* first try to find a slot in an existing linked list entry */ |
1013 | for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { | ||
1014 | rsv = __va(prsv); | ||
1015 | index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size); | ||
1016 | if (index < rsv->size) { | ||
1017 | rsv->entry[index].base = addr; | ||
1018 | rsv->entry[index].size = size; | ||
1019 | |||
1020 | return 0; | ||
1021 | } | ||
1022 | } | ||
1023 | |||
1024 | /* no slot found - allocate a new linked list entry */ | ||
1025 | rsv = (struct linux_efi_memreserve *)__get_free_page(GFP_ATOMIC); | ||
1013 | if (!rsv) | 1026 | if (!rsv) |
1014 | return -ENOMEM; | 1027 | return -ENOMEM; |
1015 | 1028 | ||
1016 | rsv->size = 1; | 1029 | rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE); |
1017 | atomic_set(&rsv->count, 1); | 1030 | atomic_set(&rsv->count, 1); |
1018 | rsv->entry[0].base = addr; | 1031 | rsv->entry[0].base = addr; |
1019 | rsv->entry[0].size = size; | 1032 | rsv->entry[0].size = size; |
diff --git a/include/linux/efi.h b/include/linux/efi.h index 4f27640fdcdc..becd5d76a207 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h | |||
@@ -1724,4 +1724,7 @@ struct linux_efi_memreserve { | |||
1724 | #define EFI_MEMRESERVE_SIZE(count) (sizeof(struct linux_efi_memreserve) + \ | 1724 | #define EFI_MEMRESERVE_SIZE(count) (sizeof(struct linux_efi_memreserve) + \ |
1725 | (count) * sizeof(((struct linux_efi_memreserve *)0)->entry[0])) | 1725 | (count) * sizeof(((struct linux_efi_memreserve *)0)->entry[0])) |
1726 | 1726 | ||
1727 | #define EFI_MEMRESERVE_COUNT(size) (((size) - sizeof(struct linux_efi_memreserve)) \ | ||
1728 | / sizeof(((struct linux_efi_memreserve *)0)->entry[0])) | ||
1729 | |||
1727 | #endif /* _LINUX_EFI_H */ | 1730 | #endif /* _LINUX_EFI_H */ |