29 Mar, 2014
1 commit
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During pcpu_alloc_area(), we might merge the current head with the
previous block. Since we have calculated the max_contig using the
size of previous block before we skip it, and now we update the size
of previous block, so we should renew the max_contig.Signed-off-by: Jianyu Zhan
Signed-off-by: Tejun Heo
18 Mar, 2014
1 commit
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723ad1d90b56 ("percpu: store offsets instead of lengths in ->map[]")
updated percpu area allocator to use the lowest bit, instead of sign,
to signify whether the area is occupied and forced min align to 2;
unfortunately, it forgot to force the allocation size to be even
causing malfunctions for the very rare odd-sized allocations.Always force the allocations to be even sized.
tj: Wrote patch description.
Original-patch-by: Al Viro
Signed-off-by: Tejun Heo
07 Mar, 2014
3 commits
-
If we know that first N areas are all in use, we can obviously skip
them when searching for a free one. And that kind of hint is very
easy to maintain.Signed-off-by: Al Viro
Signed-off-by: Tejun Heo -
Current code keeps +-length for each area in chunk->map[]. It has
several unpleasant consequences:
* even if we know that first 50 areas are all in use, allocation
still needs to go through all those areas just to sum their sizes, just
to get the offset of free one.
* freeing needs to find the array entry refering to the area
in question; again, the need to sum the sizes until we reach the offset
we are interested in. Note that offsets are monotonous, so simple
binary search would do here.New data representation: array of pairs.
Each pair is represented by one int - we use offset|1 for
and offset for (we make sure that all offsets are even).
In the end we put a sentry entry - . The first
entry is ; it would be possible to store together the flag
for Nth area and offset for N+1st, but that leads to much hairier code.In other words, where the old variant would have
4, -8, -4, 4, -12, 100
(4 bytes free, 8 in use, 4 in use, 4 free, 12 in use, 100 free) we store
, , , , , ,
i.e.
0, 5, 13, 16, 21, 32, 133This commit switches to new data representation and takes care of a couple
of low-hanging fruits in free_pcpu_area() - one is the switch to binary
search, another is not doing two memmove() when one would do. Speeding
the alloc side up (by keeping track of how many areas in the beginning are
known to be all in use) also becomes possible - that'll be done in the next
commit.Signed-off-by: Al Viro
Signed-off-by: Tejun Heo -
... and simplify the results a bit. Makes the next step easier
to deal with - we will be changing the data representation for
chunk->map[] and it's easier to do if the code in question is
not split between pcpu_alloc_area() and pcpu_split_block().Signed-off-by: Al Viro
Signed-off-by: Tejun Heo
22 Jan, 2014
2 commits
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Merge first patch-bomb from Andrew Morton:
- a couple of misc things
- inotify/fsnotify work from Jan
- ocfs2 updates (partial)
- about half of MM
* emailed patches from Andrew Morton : (117 commits)
mm/migrate: remove unused function, fail_migrate_page()
mm/migrate: remove putback_lru_pages, fix comment on putback_movable_pages
mm/migrate: correct failure handling if !hugepage_migration_support()
mm/migrate: add comment about permanent failure path
mm, page_alloc: warn for non-blockable __GFP_NOFAIL allocation failure
mm: compaction: reset scanner positions immediately when they meet
mm: compaction: do not mark unmovable pageblocks as skipped in async compaction
mm: compaction: detect when scanners meet in isolate_freepages
mm: compaction: reset cached scanner pfn's before reading them
mm: compaction: encapsulate defer reset logic
mm: compaction: trace compaction begin and end
memcg, oom: lock mem_cgroup_print_oom_info
sched: add tracepoints related to NUMA task migration
mm: numa: do not automatically migrate KSM pages
mm: numa: trace tasks that fail migration due to rate limiting
mm: numa: limit scope of lock for NUMA migrate rate limiting
mm: numa: make NUMA-migrate related functions static
lib/show_mem.c: show num_poisoned_pages when oom
mm/hwpoison: add '#' to hwpoison_inject
mm/memblock: use WARN_ONCE when MAX_NUMNODES passed as input parameter
... -
Switch to memblock interfaces for early memory allocator instead of
bootmem allocator. No functional change in beahvior than what it is in
current code from bootmem users points of view.Archs already converted to NO_BOOTMEM now directly use memblock
interfaces instead of bootmem wrappers build on top of memblock. And
the archs which still uses bootmem, these new apis just fallback to
exiting bootmem APIs.Signed-off-by: Santosh Shilimkar
Cc: "Rafael J. Wysocki"
Cc: Arnd Bergmann
Cc: Christoph Lameter
Cc: Greg Kroah-Hartman
Cc: Grygorii Strashko
Cc: H. Peter Anvin
Cc: Johannes Weiner
Cc: KAMEZAWA Hiroyuki
Cc: Konrad Rzeszutek Wilk
Cc: Michal Hocko
Cc: Paul Walmsley
Cc: Pavel Machek
Cc: Russell King
Cc: Tejun Heo
Cc: Tony Lindgren
Cc: Yinghai Lu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 Jan, 2014
1 commit
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vmalloc already gives a useful macro to calculate the total vmalloc
size. Use it.Signed-off-by: Laura Abbott
Signed-off-by: Tejun Heo
23 Sep, 2013
1 commit
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If memory allocation of in pcpu_embed_first_chunk() fails, the
allocated memory is not released correctly. In the release loop also
the non-allocated elements are released which leads to the following
kernel BUG on systems with very little memory:[ 0.000000] kernel BUG at mm/bootmem.c:307!
[ 0.000000] illegal operation: 0001 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0 #22
[ 0.000000] task: 0000000000a20ae0 ti: 0000000000a08000 task.ti: 0000000000a08000
[ 0.000000] Krnl PSW : 0400000180000000 0000000000abda7a (__free+0x116/0x154)
[ 0.000000] R:0 T:1 IO:0 EX:0 Key:0 M:0 W:0 P:0 AS:0 CC:0 PM:0 EA:3
...
[ 0.000000] [] mark_bootmem_node+0xde/0xf0
[ 0.000000] [] mark_bootmem+0xa8/0x118
[ 0.000000] [] pcpu_embed_first_chunk+0xe7a/0xf0c
[ 0.000000] [] setup_per_cpu_areas+0x4a/0x28cTo fix the problem now only allocated elements are released. This then
leads to the correct kernel panic:[ 0.000000] Kernel panic - not syncing: Failed to initialize percpu areas.
...
[ 0.000000] Call Trace:
[ 0.000000] ([] show_trace+0x132/0x150)
[ 0.000000] [] show_stack+0xc4/0xd4
[ 0.000000] [] dump_stack+0x74/0xd8
[ 0.000000] [] panic+0xea/0x264
[ 0.000000] [] setup_per_cpu_areas+0x5c/0x28ctj: Flipped if conditional so that it doesn't need "continue".
Signed-off-by: Michael Holzheu
Signed-off-by: Tejun Heo
02 Dec, 2012
1 commit
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Otherwise we are getting a nil dereference if percpu_alloc kernel boot
argument is specified without value.| [ 0.000000] BUG: unable to handle kernel NULL pointer dereference at (null)
| [ 0.000000] IP: [] strcmp+0x10/0x30Signed-off-by: Cyrill Gorcunov
Signed-off-by: Tejun Heo
29 Oct, 2012
1 commit
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commit 099a19d9('allow limited allocation before slab is online') made
pcpu_alloc_chunk() use pcpu_mem_zalloc() but forgot to update
pcpu_free_chunk() accordingly. This doesn't cause any immediate
problema, but fix it for consistency.tj: commit message updated
Signed-off-by: Joonsoo Kim
Cc: Christoph Lameter
Signed-off-by: Tejun Heo
06 Oct, 2012
1 commit
-
Signed-off-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 May, 2012
2 commits
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Kmemleak tracks the percpu allocations via a specific API and the
originally allocated areas must be removed from kmemleak (via
kmemleak_free). The code was already doing this for SMP systems.Reported-by: Sami Liedes
Cc: Tejun Heo
Cc: Christoph Lameter
Signed-off-by: Catalin Marinas
Signed-off-by: Tejun Heo -
pcpu_embed_first_chunk() allocates memory for each node, copies percpu
data and frees unused portions of it before proceeding to the next
group. This assumes that allocations for different nodes doesn't
overlap; however, depending on memory topology, the bootmem allocator
may end up allocating memory from a different node than the requested
one which may overlap with the portion freed from one of the previous
percpu areas. This leads to percpu groups for different nodes
overlapping which is a serious bug.This patch separates out copy & partial free from the allocation loop
such that all allocations are complete before partial frees happen.This also fixes overlapping frees which could happen on allocation
failure path - out_free_areas path frees whole groups but the groups
could have portions freed at that point.Signed-off-by: Tejun Heo
Cc: stable@vger.kernel.org
Reported-by: "Pavel V. Panteleev"
Tested-by: "Pavel V. Panteleev"
LKML-Reference:
30 Mar, 2012
1 commit
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pcpu_dump_alloc_info() was printing continued lines without KERN_CONT.
Use it.Signed-off-by: Tejun Heo
Reported-by: Kay Sievers
15 Jan, 2012
1 commit
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Kmemleak patches
Main features:
- Handle percpu memory allocations (only scanning them, not actually
reporting).
- Memory hotplug support.Usability improvements:
- Show the origin of early allocations.
- Report previously found leaks even if kmemleak has been disabled by
some error.* tag 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux:
kmemleak: Add support for memory hotplug
kmemleak: Handle percpu memory allocation
kmemleak: Report previously found leaks even after an error
kmemleak: When the early log buffer is exceeded, report the actual number
kmemleak: Show where early_log issues come from
16 Dec, 2011
1 commit
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per_cpu_ptr_to_phys() incorrectly rounds up its result for non-kmalloc
case to the page boundary, which is bogus for any non-page-aligned
address.This affects the only in-tree user of this function - sysfs handler
for per-cpu 'crash_notes' physical address. The trouble is that the
crash_notes per-cpu variable is not page-aligned:crash_notes = 0xc08e8ed4
PER-CPU OFFSET VALUES:
CPU 0: 3711f000
CPU 1: 37129000
CPU 2: 37133000
CPU 3: 3713d000So, the per-cpu addresses are:
crash_notes on CPU 0: f7a07ed4 => phys 36b57ed4
crash_notes on CPU 1: f7a11ed4 => phys 36b4ded4
crash_notes on CPU 2: f7a1bed4 => phys 36b43ed4
crash_notes on CPU 3: f7a25ed4 => phys 36b39ed4However, /sys/devices/system/cpu/cpu*/crash_notes says:
/sys/devices/system/cpu/cpu0/crash_notes: 36b57000
/sys/devices/system/cpu/cpu1/crash_notes: 36b4d000
/sys/devices/system/cpu/cpu2/crash_notes: 36b43000
/sys/devices/system/cpu/cpu3/crash_notes: 36b39000As you can see, all values are rounded down to a page
boundary. Consequently, this is where kexec sets up the NOTE segments,
and thus where the secondary kernel is looking for them. However, when
the first kernel crashes, it saves the notes to the unaligned
addresses, where they are not found.Fix it by adding offset_in_page() to the translated page address.
-tj: Combined Eugene's and Petr's commit messages.
Signed-off-by: Eugene Surovegin
Signed-off-by: Tejun Heo
Reported-by: Petr Tesarik
Cc: stable@kernel.org
03 Dec, 2011
1 commit
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This patch adds kmemleak callbacks from the percpu allocator, reducing a
number of false positives caused by kmemleak not scanning such memory
blocks. The percpu chunks are never reported as leaks because of current
kmemleak limitations with the __percpu pointer not pointing directly to
the actual chunks.Reported-by: Huajun Li
Acked-by: Christoph Lameter
Acked-by: Tejun Heo
Signed-off-by: Catalin Marinas
24 Nov, 2011
1 commit
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Add comments about current per_cpu_ptr_to_phys implementation to
explain why the logic is more complicated than necessary.-tj: relocated comment into kerneldoc comment
Signed-off-by: Dave Young
Signed-off-by: Tejun Heo
23 Nov, 2011
2 commits
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Percpu allocator recorded the cpus which map to the first and last
units in pcpu_first/last_unit_cpu respectively and used them to
determine the address range of a chunk - e.g. it assumed that the
first unit has the lowest address in a chunk while the last unit has
the highest address.This simply isn't true. Groups in a chunk can have arbitrary positive
or negative offsets from the previous one and there is no guarantee
that the first unit occupies the lowest offset while the last one the
highest.Fix it by actually comparing unit offsets to determine cpus occupying
the lowest and highest offsets. Also, rename pcu_first/last_unit_cpu
to pcpu_low/high_unit_cpu to avoid confusion.The chunk address range is used to flush cache on vmalloc area
map/unmap and decide whether a given address is in the first chunk by
per_cpu_ptr_to_phys() and the bug was discovered by invalid
per_cpu_ptr_to_phys() translation for crash_note.Kudos to Dave Young for tracking down the problem.
Signed-off-by: Tejun Heo
Reported-by: WANG Cong
Reported-by: Dave Young
Tested-by: Dave Young
LKML-Reference:
Cc: stable @kernel.org -
Currently pcpu_mem_alloc() is implemented always return zeroed memory.
So rename it to make user like pcpu_get_pages_and_bitmap() know don't
reinit it.Signed-off-by: Bob Liu
Reviewed-by: Pekka Enberg
Reviewed-by: Michal Hocko
Signed-off-by: Tejun Heo
25 May, 2011
1 commit
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* 'for-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: Unify input section names
percpu: Avoid extra NOP in percpu_cmpxchg16b_double
percpu: Cast away printk format warning
percpu: Always align percpu output section to PAGE_SIZEFix up fairly trivial conflict in arch/x86/include/asm/percpu.h as per Tejun
24 May, 2011
1 commit
31 Mar, 2011
1 commit
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Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: Lucas De Marchi
29 Mar, 2011
1 commit
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On 32-bit systems which don't happen to implicitly define or cast
VMALLOC_START and/or VMALLOC_END to long in their arch headers, the
printk in the percpu code will cause a warning to be emitted:mm/percpu.c: In function 'pcpu_embed_first_chunk':
mm/percpu.c:1648: warning: format '%lx' expects type 'long unsigned int',
but argument 3 has type 'unsigned int'So add an explicit cast to unsigned long here.
Signed-off-by: Mike Frysinger
Signed-off-by: Tejun Heo
28 Mar, 2011
1 commit
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per_cpu_ptr_to_phys() uses VMALLOC_START and VMALLOC_END to determine if an
address is in the vmalloc() region or not. This is incorrect on NOMMU as
there is no real vmalloc() capability (vmalloc() is emulated by kmalloc()).The correct way to do this is to use is_vmalloc_addr(). This encapsulates the
vmalloc() region test in MMU mode and just returns 0 in NOMMU mode.On FRV in NOMMU mode, the percpu compilation fails without this patch:
mm/percpu.c: In function 'per_cpu_ptr_to_phys':
mm/percpu.c:1011: error: 'VMALLOC_START' undeclared (first use in this function)
mm/percpu.c:1011: error: (Each undeclared identifier is reported only once
mm/percpu.c:1011: error: for each function it appears in.)
mm/percpu.c:1012: error: 'VMALLOC_END' undeclared (first use in this function)
mm/percpu.c:1018: warning: control reaches end of non-void functionSigned-off-by: David Howells
25 Mar, 2011
1 commit
-
Percpu allocator honors alignment request upto PAGE_SIZE and both the
percpu addresses in the percpu address space and the translated kernel
addresses should be aligned accordingly. The calculation of the
former depends on the alignment of percpu output section in the kernel
image.The linker script macros PERCPU_VADDR() and PERCPU() are used to
define this output section and the latter takes @align parameter.
Several architectures are using @align smaller than PAGE_SIZE breaking
percpu memory alignment.This patch removes @align parameter from PERCPU(), renames it to
PERCPU_SECTION() and makes it always align to PAGE_SIZE. While at it,
add PCPU_SETUP_BUG_ON() checks such that alignment problems are
reliably detected and remove percpu alignment comment recently added
in workqueue.c as the condition would trigger BUG way before reaching
there.For um, this patch raises the alignment of percpu area. As the area
is in .init, there shouldn't be any noticeable difference.This problem was discovered by David Howells while debugging boot
failure on mn10300.Signed-off-by: Tejun Heo
Acked-by: Mike Frysinger
Cc: uclinux-dist-devel@blackfin.uclinux.org
Cc: David Howells
Cc: Jeff Dike
Cc: user-mode-linux-devel@lists.sourceforge.net
14 Jan, 2011
1 commit
-
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits)
Documentation/trace/events.txt: Remove obsolete sched_signal_send.
writeback: fix global_dirty_limits comment runtime -> real-time
ppc: fix comment typo singal -> signal
drivers: fix comment typo diable -> disable.
m68k: fix comment typo diable -> disable.
wireless: comment typo fix diable -> disable.
media: comment typo fix diable -> disable.
remove doc for obsolete dynamic-printk kernel-parameter
remove extraneous 'is' from Documentation/iostats.txt
Fix spelling milisec -> ms in snd_ps3 module parameter description
Fix spelling mistakes in comments
Revert conflicting V4L changes
i7core_edac: fix typos in comments
mm/rmap.c: fix comment
sound, ca0106: Fix assignment to 'channel'.
hrtimer: fix a typo in comment
init/Kconfig: fix typo
anon_inodes: fix wrong function name in comment
fix comment typos concerning "consistent"
poll: fix a typo in comment
...Fix up trivial conflicts in:
- drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c)
- fs/ext4/ext4.hAlso fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.
08 Jan, 2011
1 commit
-
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits)
gameport: use this_cpu_read instead of lookup
x86: udelay: Use this_cpu_read to avoid address calculation
x86: Use this_cpu_inc_return for nmi counter
x86: Replace uses of current_cpu_data with this_cpu ops
x86: Use this_cpu_ops to optimize code
vmstat: User per cpu atomics to avoid interrupt disable / enable
irq_work: Use per cpu atomics instead of regular atomics
cpuops: Use cmpxchg for xchg to avoid lock semantics
x86: this_cpu_cmpxchg and this_cpu_xchg operations
percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support
percpu,x86: relocate this_cpu_add_return() and friends
connector: Use this_cpu operations
xen: Use this_cpu_inc_return
taskstats: Use this_cpu_ops
random: Use this_cpu_inc_return
fs: Use this_cpu_inc_return in buffer.c
highmem: Use this_cpu_xx_return() operations
vmstat: Use this_cpu_inc_return for vm statistics
x86: Support for this_cpu_add, sub, dec, inc_return
percpu: Generic support for this_cpu_add, sub, dec, inc_return
...Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c}
as per Tejun.
22 Dec, 2010
1 commit
-
Now that percpu allocator is mostly stable, there is no reason to
print alloc information with KERN_INFO and clutter the boot messages.
Switch it to KERN_DEBUG.Signed-off-by: Tejun Heo
Cc: Ingo Molnar
Cc: Mike Travis
07 Dec, 2010
1 commit
-
Don't do vmalloc() + memset() when vzalloc() will do.
tj: dropped unnecessary temp variable ptr.
Signed-off-by: Jesper Juhl
Signed-off-by: Tejun Heo
02 Nov, 2010
1 commit
-
"gadget", "through", "command", "maintain", "maintain", "controller", "address",
"between", "initiali[zs]e", "instead", "function", "select", "already",
"equal", "access", "management", "hierarchy", "registration", "interest",
"relative", "memory", "offset", "already",Signed-off-by: Uwe Kleine-König
Signed-off-by: Jiri Kosina
25 Oct, 2010
1 commit
-
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
Update broken web addresses in arch directory.
Update broken web addresses in the kernel.
Revert "drivers/usb: Remove unnecessary return's from void functions" for musb gadget
Revert "Fix typo: configuation => configuration" partially
ida: document IDA_BITMAP_LONGS calculation
ext2: fix a typo on comment in ext2/inode.c
drivers/scsi: Remove unnecessary casts of private_data
drivers/s390: Remove unnecessary casts of private_data
net/sunrpc/rpc_pipe.c: Remove unnecessary casts of private_data
drivers/infiniband: Remove unnecessary casts of private_data
drivers/gpu/drm: Remove unnecessary casts of private_data
kernel/pm_qos_params.c: Remove unnecessary casts of private_data
fs/ecryptfs: Remove unnecessary casts of private_data
fs/seq_file.c: Remove unnecessary casts of private_data
arm: uengine.c: remove C99 comments
arm: scoop.c: remove C99 comments
Fix typo configue => configure in comments
Fix typo: configuation => configuration
Fix typo interrest[ing|ed] => interest[ing|ed]
Fix various typos of valid in comments
...Fix up trivial conflicts in:
drivers/char/ipmi/ipmi_si_intf.c
drivers/usb/gadget/rndis.c
net/irda/irnet/irnet_ppp.c
23 Oct, 2010
1 commit
-
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: update comments to reflect that percpu allocations are always zero-filled
percpu: Optimize __get_cpu_var()
x86, percpu: Optimize this_cpu_ptr
percpu: clear memory allocated with the km allocator
percpu: fix build breakage on s390 and cleanup build configuration tests
percpu: use percpu allocator on UP too
percpu: reduce PCPU_MIN_UNIT_SIZE to 32k
vmalloc: pcpu_get/free_vm_areas() aren't needed on UPFixed up trivial conflicts in include/linux/percpu.h
21 Sep, 2010
1 commit
-
pcpu_first/last_unit_cpu are used to track which cpu has the first and
last units assigned. This in turn is used to determine the span of a
chunk for man/unmap cache flushes and whether an address belongs to
the first chunk or not in per_cpu_ptr_to_phys().When the number of possible CPUs isn't power of two, a chunk may
contain unassigned units towards the end of a chunk. The logic to
determine pcpu_last_unit_cpu was incorrect when there was an unused
unit at the end of a chunk. It failed to ignore the unused unit and
assigned the unused marker NR_CPUS to pcpu_last_unit_cpu.This was discovered through kdump failure which was caused by
malfunctioning per_cpu_ptr_to_phys() on a kvm setup with 50 possible
CPUs by CAI Qian.Signed-off-by: Tejun Heo
Reported-by: CAI Qian
Cc: stable@kernel.org
10 Sep, 2010
2 commits
-
Signed-off-by: Tejun Heo
Reported-by: Stephane Eranian -
Commit bbddff05 (percpu: use percpu allocator on UP too) incorrectly
excluded pcpu_build_alloc_info() on SMP configurations which use
generic setup_per_cpu_area() like s390. The config ifdefs are
becoming confusing. Fix and clean it up by,* Move pcpu_build_alloc_info() right on top of its two users -
pcpu_{embed|page}_first_chunk() which are already in CONFIG_SMP
block.* Define BUILD_{EMBED|PAGE}_FIRST_CHUNK which indicate whether each
first chunk function needs to be included and use them to control
inclusion of the three functions to reduce confusion.Signed-off-by: Tejun Heo
Reported-by: Sachin Sant
08 Sep, 2010
1 commit
-
On UP, percpu allocations were redirected to kmalloc. This has the
following problems.* For certain amount of allocations (determined by
PERCPU_DYNAMIC_EARLY_SLOTS and PERCPU_DYNAMIC_EARLY_SIZE), percpu
allocator can be used before the usual kernel memory allocator is
brought online. On SMP, this is used to initialize the kernel
memory allocator.* percpu allocator honors alignment upto PAGE_SIZE but kmalloc()
doesn't. For example, workqueue makes use of larger alignments for
cpu_workqueues.Currently, users of percpu allocators need to handle UP differently,
which is somewhat fragile and ugly. Other than small amount of
memory, there isn't much to lose by enabling percpu allocator on UP.
It can simply use kernel memory based chunk allocation which was added
for SMP archs w/o MMUs.This patch removes mm/percpu_up.c, builds mm/percpu.c on UP too and
makes UP build use percpu-km. As percpu addresses and kernel
addresses are always identity mapped and static percpu variables don't
need any special treatment, nothing is arch dependent and mm/percpu.c
implements generic setup_per_cpu_areas() for UP.Signed-off-by: Tejun Heo
Reviewed-by: Christoph Lameter
Acked-by: Pekka Enberg
27 Aug, 2010
2 commits
-
When pcpu_build_alloc_info() searches best_upa value, it ignores current value
if the number of waste units exceeds 1/3 of the number of total cpus. But the
comment on the code says that it will ignore if wastage is over 25%.
Modify the comment.Signed-off-by: Namhyung Kim
Signed-off-by: Tejun Heo -
The original code did not free the old map. This patch fixes it.
tj: use @old as memcpy source instead of @chunk->map, and indentation
and description updateSigned-off-by: Huang Shijie
Signed-off-by: Tejun Heo
Cc: stable@kernel.org
