- 14 Feb, 2015 11 commits
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Andrzej Hajda authored
kstrdup() is often used to duplicate strings where neither source neither destination will be ever modified. In such case we can just reuse the source instead of duplicating it. The problem is that we must be sure that the source is non-modifiable and its life-time is long enough. I suspect the good candidates for such strings are strings located in kernel .rodata section, they cannot be modifed because the section is read-only and their life-time is equal to kernel life-time. This small patchset proposes alternative version of kstrdup - kstrdup_const, which returns source string if it is located in .rodata otherwise it fallbacks to kstrdup. To verify if the source is in .rodata function checks if the address is between sentinels __start_rodata, __end_rodata. I guess it should work with all architectures. The main patch is accompanied by four patches constifying kstrdup for cases where situtation described above happens frequently. I have tested the patchset on mobile platform (exynos4210-trats) and it saves 3272 string allocations. Since minimal allocation is 32 or 64 bytes depending on Kconfig options the patchset saves respectively about 100KB or 200KB of memory. Stats from tested platform show that the main offender is sysfs: By caller: 2260 __kernfs_new_node 631 clk_register+0xc8/0x1b8 318 clk_register+0x34/0x1b8 51 kmem_cache_create 12 alloc_vfsmnt By string (with count >= 5): 883 power 876 subsystem 135 parameters 132 device 61 iommu_group ... This patch (of 5): Add an alternative version of kstrdup which returns pointer to constant char array. The function checks if input string is in persistent and read-only memory section, if yes it returns the input string, otherwise it fallbacks to kstrdup. kstrdup_const is accompanied by kfree_const performing conditional memory deallocation of the string. Signed-off-by:Andrzej Hajda <a.hajda@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Mike Turquette <mturquette@linaro.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Tejun Heo <tj@kernel.org> Cc: Greg KH <greg@kroah.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Daniel Borkmann authored
Commit 8f243af4 ("sections: fix const sections for crc32 table") removed the compile-time generated crc32 tables from the RO sections, because it conflicts with the definition of __cacheline_aligned which puts all such aligned data into .data..cacheline_aligned section optimized for wasting less space, and can cause alignment issues when used in combination with const with some gcc versions like 4.7.0 due to a gcc bug [1]. Given that most gcc versions should have the fix by now, we can just use ____cacheline_aligned, which only aligns the data but doesn't move it into specific sections as opposed to __cacheline_aligned. In case of gcc versions having the mentioned bug, the alignment attribute will have no effect, but the data will still be made RO. After patch tables are in RO: $ nm -v lib/crc32.o | grep -1 -E "crc32c?table" 0000000000000000 t arch_local_irq_enable 0000000000000000 r crc32ctable_le 0000000000000000 t crc32_exit -- 0000000000000960 t test_buf 0000000000002000 r crc32table_be 0000000000004000 r crc32table_le 000000001d1056e5 A __crc_crc32_be [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52181Signed-off-by:
Daniel Borkmann <dborkman@redhat.com> Cc: Joe Mario <jmario@redhat.com> Signed-off-by:
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Rasmus Villemoes authored
The first of these conditionals is completely redundant: If k == lim-1, we must have off==0, so the second conditional will also trigger and then it wouldn't matter if upper had some high bits set. But the second conditional is in fact also redundant, since it only serves to clear out some high-order "don't care" bits of dst, about which no guarantee is made. Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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Rasmus Villemoes authored
We can shift the bits from lower and upper into place before assembling dst[k + off]; moving the shift of lower into the branch where we already know that rem is non-zero allows us to remove a conditional. Signed-off-by:
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Rasmus Villemoes authored
gcc can generate slightly better code for stuff like "nbits % BITS_PER_LONG" when it knows nbits is not negative. Since negative size bitmaps or shift amounts don't make sense, change these parameters of bitmap_shift_right to unsigned. If off >= lim (which requires shift >= nbits), k is initialized with a large positive value, but since I've let k continue to be signed, the loop will never run and dst will be zeroed as expected. Inside the loop, k is guaranteed to be non-negative, so the fact that it is promoted to unsigned in the various expressions it appears in is harmless. Also use "shift" and "nbits" consistently for the parameter names. Signed-off-by:
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Rasmus Villemoes authored
If left is 0, we can just let mask be ~0UL, so that anding with it is a no-op. Conveniently, BITMAP_LAST_WORD_MASK provides precisely what we need, and we can eliminate left. Signed-off-by:
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Rasmus Villemoes authored
If the condition k==lim-1 is true, we must have off == 0 (otherwise, k could never become that big). But in that case we have upper == 0 and hence dst[k] == (src[k] & mask) >> rem. Since mask consists of a consecutive range of bits starting from the LSB, anding dst[k] with mask is a no-op. Signed-off-by:
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Rasmus Villemoes authored
We can shift the bits from lower and upper into place before assembling dst[k]; moving the shift of upper into the branch where we already know that rem is non-zero allows us to remove a conditional. Signed-off-by:
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Rasmus Villemoes authored
I've previously changed the nbits parameter of most bitmap_* functions to unsigned; now it is bitmap_shift_{left,right}'s turn. This alone saves some .text, but while at it I found that there were a few other things one could do. The end result of these seven patches is $ scripts/bloat-o-meter /tmp/bitmap.o.{old,new} add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-328 (-328) function old new delta __bitmap_shift_right 384 226 -158 __bitmap_shift_left 306 136 -170 and less importantly also a smaller stack footprint $ stack-o-meter.pl master bitmap file function old new delta lib/bitmap.o __bitmap_shift_right 24 8 -16 lib/bitmap.o __bitmap_shift_left 24 0 -24 For each pair of 0 <= shift <= nbits <= 256 I've tested the end result with a few randomly filled src buffers (including garbage beyond nbits), in each case verifying that the shift {left,right}-most bits of dst are zero and the remaining nbits-shift bits correspond to src, so I'm fairly confident I didn't screw up. That hasn't stopped me from being wrong before, though. This patch (of 7): gcc can generate slightly better code for stuff like "nbits % BITS_PER_LONG" when it knows nbits is not negative. Since negative size bitmaps or shift amounts don't make sense, change these parameters of bitmap_shift_right to unsigned. The expressions involving "lim - 1" are still ok, since if lim is 0 the loop is never executed. Also use "shift" and "nbits" consistently for the parameter names. Signed-off-by: -
Rasmus Villemoes authored
On little-endian, there's no reason to have an extra, presumably less efficient, way of copying a bitmap. Signed-off-by:
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Rasmus Villemoes authored
Make the prototype of bitmap_copy_le the same as bitmap_copy's. All other bitmap_* functions take unsigned long* parameters; there's no reason this should be special. The only current user is the static inline uwb_mas_bm_copy_le, which already does the void* laundering, so the end users can pass their u8 or __le32 buffers without a cast. Furthermore, this allows us to simply let bitmap_copy_le be an alias for bitmap_copy on little-endian; see next patch. Signed-off-by:
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- 13 Feb, 2015 29 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-ledsLinus Torvalds authored
Pull LED subsystem update from Bryan Wu: "The big change of LED subsystem is introducing a new LED class for Flash type LEDs which will be used for V4L2 subsystem. Also we got some cleanup and fixes" * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds: leds: leds-gpio: Pass on error codes unmodified DT: leds: Add led-sources property leds: Add LED Flash class extension to the LED subsystem leds: leds-mc13783: Use of_get_child_by_name() instead of refcount hack leds: Use setup_timer leds: Don't allow brightness values greater than max_brightness DT: leds: Add flash LED devices related properties
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git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linuxLinus Torvalds authored
Pull module update from Rusty Russell: "Trivial cleanups, mainly" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: module: Replace over-engineered nested sleep module: Annotate nested sleep in resolve_symbol() module: Remove double spaces in module verification taint message kernel/module.c: Free lock-classes if parse_args failed module: set ksymtab/kcrctab* section addresses to 0x0
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git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds authored
Pull arch/tile changes from Chris Metcalf: "Not much in this batch, just some minor cleanups" * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: tile: change MAINTAINERS website from tilera.com to ezchip.com tile: enable sparse checks for get/put_user tile: fix put_user sparse errors tile: default to little endian on older toolchains
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Linus Torvalds authored
This reverts commit 5fcee53c. It causes the suspend to fail on at least the Chromebook Pixel, possibly other platforms too. Joerg Roedel points out that the logic should probably have been if (max_physical_apicid > 255 || !(IS_ENABLED(CONFIG_HYPERVISOR_GUEST) && hypervisor_x2apic_available())) { instead, but since the code is not in any fast-path, so we can just live without that optimization and just revert to the original code. Acked-by:
Joerg Roedel <joro@8bytes.org> Acked-by:
Jiang Liu <jiang.liu@linux.intel.com> Signed-off-by:
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Chris Metcalf authored
Signed-off-by:Chris Metcalf <cmetcalf@ezchip.com>
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull KVM update from Paolo Bonzini: "Fairly small update, but there are some interesting new features. Common: Optional support for adding a small amount of polling on each HLT instruction executed in the guest (or equivalent for other architectures). This can improve latency up to 50% on some scenarios (e.g. O_DSYNC writes or TCP_RR netperf tests). This also has to be enabled manually for now, but the plan is to auto-tune this in the future. ARM/ARM64: The highlights are support for GICv3 emulation and dirty page tracking s390: Several optimizations and bugfixes. Also a first: a feature exposed by KVM (UUID and long guest name in /proc/sysinfo) before it is available in IBM's hypervisor! :) MIPS: Bugfixes. x86: Support for PML (page modification logging, a new feature in Broadwell Xeons that speeds up dirty page tracking), nested virtualization improvements (nested APICv---a nice optimization), usual round of emulation fixes. There is also a new option to reduce latency of the TSC deadline timer in the guest; this needs to be tuned manually. Some commits are common between this pull and Catalin's; I see you have already included his tree. Powerpc: Nothing yet. The KVM/PPC changes will come in through the PPC maintainers, because I haven't received them yet and I might end up being offline for some part of next week" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (130 commits) KVM: ia64: drop kvm.h from installed user headers KVM: x86: fix build with !CONFIG_SMP KVM: x86: emulate: correct page fault error code for NoWrite instructions KVM: Disable compat ioctl for s390 KVM: s390: add cpu model support KVM: s390: use facilities and cpu_id per KVM KVM: s390/CPACF: Choose crypto control block format s390/kernel: Update /proc/sysinfo file with Extended Name and UUID KVM: s390: reenable LPP facility KVM: s390: floating irqs: fix user triggerable endless loop kvm: add halt_poll_ns module parameter kvm: remove KVM_MMIO_SIZE KVM: MIPS: Don't leak FPU/DSP to guest KVM: MIPS: Disable HTW while in guest KVM: nVMX: Enable nested posted interrupt processing KVM: nVMX: Enable nested virtual interrupt delivery KVM: nVMX: Enable nested apic register virtualization KVM: nVMX: Make nested control MSRs per-cpu KVM: nVMX: Enable nested virtualize x2apic mode KVM: nVMX: Prepare for using hardware MSR bitmap ... -
git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fsLinus Torvalds authored
Pull f2fs updates from Jaegeuk Kim: "Major changes are to: - add f2fs_io_tracer and F2FS_IOC_GETVERSION - fix wrong acl assignment from parent - fix accessing wrong data blocks - fix wrong condition check for f2fs_sync_fs - align start block address for direct_io - add and refactor the readahead flows of FS metadata - refactor atomic and volatile write policies But most of patches are for clean-ups and minor bug fixes. Some of them refactor old code too" * tag 'for-f2fs-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (64 commits) f2fs: use spinlock for segmap_lock instead of rwlock f2fs: fix accessing wrong indexed data blocks f2fs: avoid variable length array f2fs: fix sparse warnings f2fs: allocate data blocks in advance for f2fs_direct_IO f2fs: introduce macros to convert bytes and blocks in f2fs f2fs: call set_buffer_new for get_block f2fs: check node page contents all the time f2fs: avoid data offset overflow when lseeking huge file f2fs: fix to use highmem for pages of newly created directory f2fs: introduce a batched trim f2fs: merge {invalidate,release}page for meta/node/data pages f2fs: show the number of writeback pages in stat f2fs: keep PagePrivate during releasepage f2fs: should fail mount when trying to recover data on read-only dev f2fs: split UMOUNT and FASTBOOT flags f2fs: avoid write_checkpoint if f2fs is mounted readonly f2fs: support norecovery mount option f2fs: fix not to drop mount options when retrying fill_super f2fs: merge flags in struct f2fs_sb_info ...
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Linus Torvalds authored
Merge third set of updates from Andrew Morton: - the rest of MM [ This includes getting rid of the numa hinting bits, in favor of just generic protnone logic. Yay. - Linus ] - core kernel - procfs - some of lib/ (lots of lib/ material this time) * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (104 commits) lib/lcm.c: replace include lib/percpu_ida.c: remove redundant includes lib/strncpy_from_user.c: replace module.h include lib/stmp_device.c: replace module.h include lib/sort.c: move include inside #if 0 lib/show_mem.c: remove redundant include lib/radix-tree.c: change to simpler include lib/plist.c: remove redundant include lib/nlattr.c: remove redundant include lib/kobject_uevent.c: remove redundant include lib/llist.c: remove redundant include lib/md5.c: simplify include lib/list_sort.c: rearrange includes lib/genalloc.c: remove redundant include lib/idr.c: remove redundant include lib/halfmd4.c: simplify includes lib/dynamic_queue_limits.c: simplify includes lib/sort.c: use simpler includes lib/interval_tree.c: simplify includes hexdump: make it return number of bytes placed in buffer ... -
Rasmus Villemoes authored
We don't need all the stuff kernel.h pulls in; just compiler.h since export.h doesn't do necessary #includes. This removes more than 100 dependencies. Signed-off-by:
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Rasmus Villemoes authored
These three #includes seem to be completely redundant: Removing them yields identical objdump -d output for each of {allyes,allno,def}config, and neither included file end up in the generated dependency file through some recursive include. In total, about 50 lines are eliminated from .percpu.o.cmd. Signed-off-by: -
Rasmus Villemoes authored
strncpy_from_user.c only needs EXPORT_SYMBOL, so just include compiler.h and export.h instead of the whole module.h machinery. Signed-off-by:
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Rasmus Villemoes authored
stmp_device.c only needs EXPORT_SYMBOL, so just include compiler.h and export.h instead of the whole module.h machinery. Signed-off-by:
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Rasmus Villemoes authored
The sort function and its helpers don't do memory allocation, so the slab.h include is redundant. Move it inside the #if 0 protecting the self-test, similar to how it is done in lib/list_sort.c. This removes over 450 lines from the generated dependency file. Signed-off-by:
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Rasmus Villemoes authored
show_mem.c doesn't use anything from nmi.h. Removing it yields identical objdump -d output for each of {allyes,allno,def}config and eliminates more than 100 lines in the dependency file. Signed-off-by: -
Rasmus Villemoes authored
The comment helpfully explains why hardirq.h is included, but since commit 2d4b8473 ("hardirq: Split preempt count mask definitions") in_interrupt() has been provided by preempt_mask.h. Use that instead, saving around 40 lines in the generated dependency file. Signed-off-by:
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Rasmus Villemoes authored
Removing the include of linux/spinlock.h produces byte-identical output for {allno,def}config, and identical objdump -d output for allyesconfig. In the former two cases, more than a 100 lines are eliminated from the generated dependency file. Signed-off-by: -
Rasmus Villemoes authored
nlattr.c doesn't seem to rely on anything from netdevice.h. Removing it yields identical objdump -d output for each of {allyes,allno,def}config, and eliminates more than 200 lines from the generated dependency file. Signed-off-by: -
Rasmus Villemoes authored
The file doesn't seem to use anything from linux/user_namespace.h, and removing it yields byte-identical object code and strictly fewer dependencies in the .cmd file. Signed-off-by:
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Rasmus Villemoes authored
This file doesn't seem to use anything provided by linux/interrupt.h or anything recursively included through that. Removing it produces byte-identical output, while reducing .llist.o.cmd from 541 to 156 lines. Signed-off-by:
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Rasmus Villemoes authored
md5.c doesn't use anything from kernel.h, except that that pulls in compiler.h, which is needed for the export.h to work. Signed-off-by:
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Rasmus Villemoes authored
Memory allocation only happens in the self test, just as random numbers are only used there. So move the inclusion of slab.h inside the CONFIG_TEST_LIST_SORT. We don't need module.h and all of the stuff it carries with it, so replace with export.h and compiler.h. Unfortunately, the ARRAY_SIZE macro from kernel.h requires the user to ensure bug.h is also included (for BUILD_BUG_ON_ZERO, used by __must_be_array). We used to get that through some maze of nested includes, but just include it explicitly. linux/string.h is then only included implicitly through kernel.h->printk.h->dynamic_debug.h, but only if !CONFIG_DYNAMIC_DEBUG, so just include it explicitly (for memset). objdump -d says the generated code is the same, and wc -l says that lib/.list_sort.o.cmd went from 579 to 165 lines. Signed-off-by:
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Rasmus Villemoes authored
Removing this include produces byte-identical output, and thus removes a false dependency. Signed-off-by:
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Rasmus Villemoes authored
idr.c doesn't seem to use anything from hardirq.h (or anything included from that). Removing it produces identical objdump -d output, and gives 44 fewer lines in the .idr.o.cmd dependency file. Signed-off-by:
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Rasmus Villemoes authored
We only need EXPORT_SYMBOL, so compiler.h and export.h suffice. This means linux/types.h is no longer implicitly included, so add an include of uapi/linux/types.h to linux/cryptohash.h for __u32. Other users of cryptohash.h cannot be affected, since they must already have been including uapi/linux/types.h in order for gcc not to complain about unknown types. Signed-off-by:
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Rasmus Villemoes authored
The file doesn't use anything from ctype.h. Instead of module.h, just use export.h for EXPORT_SYMBOL. The latter requires the user to include compiler.h, so do that explicitly instead of relying on some other header pulling it in. Signed-off-by:
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Rasmus Villemoes authored
sort.c doesn't use facilities from kernel.h, but does use some types defined in linux/types.h. Include the latter directly instead of relying on some other header doing it. Similarly, include linux/export.h directly instead of through module.h. This removes 80 lines from the dependency file .sort.o.cmd. Signed-off-by:
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Rasmus Villemoes authored
The file uses nothing from init.h, and also doesn't need the full module.h machinery; export.h is sufficient. The latter requires the user to ensure compiler.h is included, so do that explicitly instead of relying on some other header pulling it in. Signed-off-by:
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Andy Shevchenko authored
This patch makes hexdump return the number of bytes placed in the buffer excluding trailing NUL. In the case of overflow it returns the desired amount of bytes to produce the entire dump. Thus, it mimics snprintf(). This will be useful for users that would like to repeat with a bigger buffer. [akpm@linux-foundation.org: fix printk warning] Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by:
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Andy Shevchenko authored
Instead of doing calculations in each case of different groupsize let's do them beforehand. While there, change the switch to an if-else-if construction. Signed-off-by:
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