- 13 Feb, 2015 40 commits
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Andy Shevchenko authored
In the current implementation we have a floating ascii column in the tail of the dump. For example, for row size equal to 16 the ascii column as in following table group size \ length 8 12 16 1 50 50 50 2 22 32 42 4 20 29 38 8 19 - 36 This patch makes it the same independently of amount of bytes dumped. The change is safe since all current users, which use ASCII part of the dump, rely on the group size equal to 1. The patch doesn't change behaviour for such group size (see the table above). Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Andy Shevchenko authored
Test different scenarios of function calls located in lib/hexdump.c. Currently hex_dump_to_buffer() is only tested and test data is provided for little endian CPUs. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Toshi Kikuchi authored
Since chunk->end_addr is (chunk->start_addr + size - 1), the end address to compare should be (start + size - 1). Signed-off-by: Toshi Kikuchi <toshik@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Now that all in-tree users of strnicmp have been converted to strncasecmp, the wrapper can be removed. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: David Howells <dhowells@redhat.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Also, rename bits to nbits. Both changes for consistency with other bitmap_* functions. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Make the return value and the ord and nbits parameters of bitmap_ord_to_pos unsigned. Also, simplify the implementation and as a side effect make the result fully defined, returning nbits for ord >= weight, in analogy with what find_{first,next}_bit does. This is a better sentinel than the former ("unofficial") 0. No current users are affected by this change. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
The ordinal of a set bit is simply the number of set bits before it; counting those doesn't need to be done one bit at a time. While at it, update the parameters to unsigned int. It is not completely unthinkable that gcc would see pos as compile-time constant 0 in one of the uses of bitmap_pos_to_ord. Since the static inline frontend bitmap_weight doesn't handle nbits==0 correctly (it would behave exactly as if nbits==BITS_PER_LONG), use __bitmap_weight. Alternatively, the last line could be spelled bitmap_weight(buf, pos+1)-1, but this is simpler. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Change the sz and nbits parameters of bitmap_fold to unsigned int for consistency with other bitmap_* functions, and to save another few bytes in the generated code. [akpm@linux-foundation.org: fix kerneldoc] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Change the nbits parameter of bitmap_onto to unsigned int for consistency with other bitmap_* functions. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Since the various bitmap_* functions now take an unsigned int as nbits parameter, it makes sense to also update the various wrappers, even though they're marked as obsolete. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
Since the various bitmap_* functions now take an unsigned int as nbits parameter, it makes sense to also update the various wrappers. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
For consistency with the other bitmap_* functions, also make the nbits parameter of bitmap_zero, bitmap_fill and bitmap_copy unsigned. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
string_get_size() was documented to return an error, but in fact always returned 0. Since the output always fits in 9 bytes, just document that and let callers do what they do now: pass a small stack buffer and ignore the return value. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
The remainder from do_div is always a u32, and after size has been reduced to be below 1000 (or 1024), it certainly fits in u32. So both remainder and sf_cap can be made u32s, the format specifiers can be simplified (%lld wasn't the right thing to use for _unsigned_ long long anyway), and we can replace a do_div with an ordinary 32/32 bit division. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
While commit 3c9f3681 ("[SCSI] lib: add generic helper to print sizes rounded to the correct SI range") says that Z and Y are included in preparation for 128 bit computers, they just waste .text currently. If and when we get u128, string_get_size needs updating anyway (and ISO needs to come up with four more prefixes). Also there's no need to include and test for the NULL sentinel; once we reach "E" size is at most 18. [The test is also wrong; it should be units_str[units][i+1]; if we've reached NULL we're already doomed.] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
All callers of skip_atoi have already checked for the first character being a digit. In this case, gcc generates simpler code for a do while-loop. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
On 64 bit, size may very well be huge even if bit 31 happens to be 0. Somehow it doesn't feel right that one can pass a 5 GiB buffer but not a 3 GiB one. So cap at INT_MAX as was probably the intention all along. This is also the made-up value passed by sprintf and vsprintf. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
It seems a little simpler to consume the p from a %p specifier in format_decode, just as it is done for the surrounding %c, %s and %% cases. While there, delete a redundant and misplaced comment. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Joe Perches authored
Neaten the MODULE_PARAM_DESC message. Use 30 seconds in the comment for the zap console locks timeout. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rasmus Villemoes authored
__FUNCTION__ hasn't been treated as a string literal since gcc 3.4, so this only helps people who only test-compile using 3.3 (compiler-gcc3.h barks at anything older than that). Besides, there are almost no occurrences of __FUNCTION__ left in the tree. [akpm@linux-foundation.org: convert remaining __FUNCTION__ references] Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Cyril Bur authored
On POWER8 virtualised kernels the VTB register can be read to have a view of time that only increases while the guest is running. This will prevent guests from seeing time jump if a guest is paused for significant amounts of time. On POWER7 and below virtualised kernels stolen time is subtracted from local_clock as a best effort approximation. This will not eliminate spurious warnings in the case of a suspended guest but may reduce the occurance in the case of softlockups due to host over commit. Bare metal kernels should avoid reading the VTB as KVM does not restore sane values when not executing, the approxmation is fine as host kernels won't observe any stolen time. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Jones <drjones@redhat.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: chai wen <chaiw.fnst@cn.fujitsu.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Ben Zhang <benzh@chromium.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Cyril Bur authored
When the hypervisor pauses a virtualised kernel the kernel will observe a jump in timebase, this can cause spurious messages from the softlockup detector. Whilst these messages are harmless, they are accompanied with a stack trace which causes undue concern and more problematically the stack trace in the guest has nothing to do with the observed problem and can only be misleading. Futhermore, on POWER8 this is completely avoidable with the introduction of the Virtual Time Base (VTB) register. This patch (of 2): This permits the use of arch specific clocks for which virtualised kernels can use their notion of 'running' time, not the elpased wall time which will include host execution time. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Andrew Jones <drjones@redhat.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: chai wen <chaiw.fnst@cn.fujitsu.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Ben Zhang <benzh@chromium.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Geert Uytterhoeven authored
Everybody uses unsigned long for pgoff_t, and no one ever overrode the definition of pgoff_t. Keep it that way, and remove the option of overriding it. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Andrey Skvortsov authored
Have git ignore the Debian directory created when running: make tar-pkg / targz-pkg / tarbz2-pkg / tarxz-pkg Signed-off-by: Andrey Skvortsov <andrej.skvortzov@gmail.com> Cc: Michal Marek <mmarek@suse.cz> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Andy Lutomirski authored
If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: David Miller <davem@davemloft.net> Acked-by: Richard Weinberger <richard@nod.at> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Steven Miao <realmz6@gmail.com> Cc: Mark Salter <msalter@redhat.com> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Andy Shevchenko authored
Instead of custom approach let's use string_escape_str() to escape a given string (task_name in this case). Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rafael Aquini authored
The output of /proc/$pid/numa_maps is in terms of number of pages like anon=22 or dirty=54. Here's some output: 7f4680000000 default file=/hugetlb/bigfile anon=50 dirty=50 N0=50 7f7659600000 default file=/anon_hugepage\040(deleted) anon=50 dirty=50 N0=50 7fff8d425000 default stack anon=50 dirty=50 N0=50 Looks like we have a stack and a couple of anonymous hugetlbfs areas page which both use the same amount of memory. They don't. The 'bigfile' uses 1GB pages and takes up ~50GB of space. The anon_hugepage uses 2MB pages and takes up ~100MB of space while the stack uses normal 4k pages. You can go over to smaps to figure out what the page size _really_ is with KernelPageSize or MMUPageSize. But, I think this is a pretty nasty and counterintuitive interface as it stands. This patch introduces 'kernelpagesize_kB' line element to /proc/<pid>/numa_maps report file in order to help identifying the size of pages that are backing memory areas mapped by a given task. This is specially useful to help differentiating between HUGE and GIGANTIC page backed VMAs. This patch is based on Dave Hansen's proposal and reviewer's follow-ups taken from the following dicussion threads: * https://lkml.org/lkml/2011/9/21/454 * https://lkml.org/lkml/2014/12/20/66Signed-off-by: Rafael Aquini <aquini@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rafael Aquini authored
Add a small section to proc.txt doc in order to document its /proc/pid/numa_maps interface. It does not introduce any functional changes, just documentation. Signed-off-by: Rafael Aquini <aquini@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Alexander Kuleshov authored
Use the PDE() helper to get proc_dir_entry instead of coding it directly. Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com> Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Petr Cermak authored
Peak resident size of a process can be reset back to the process's current rss value by writing "5" to /proc/pid/clear_refs. The driving use-case for this would be getting the peak RSS value, which can be retrieved from the VmHWM field in /proc/pid/status, per benchmark iteration or test scenario. [akpm@linux-foundation.org: clarify behaviour in documentation] Signed-off-by: Petr Cermak <petrcermak@chromium.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Primiano Tucci <primiano@chromium.org> Cc: Petr Cermak <petrcermak@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rickard Strandqvist authored
Remove the function search_one_table() that is not used anywhere. This was partially found by using a static code analysis program called cppcheck. Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ganesh Mahendran authored
Keeping fragmentation of zsmalloc in a low level is our target. But now we still need to add the debug code in zsmalloc to get the quantitative data. This patch adds a new configuration CONFIG_ZSMALLOC_STAT to enable the statistics collection for developers. Currently only the objects statatitics in each class are collected. User can get the information via debugfs. cat /sys/kernel/debug/zsmalloc/zram0/... For example: After I copied "jdk-8u25-linux-x64.tar.gz" to zram with ext4 filesystem: class size obj_allocated obj_used pages_used 0 32 0 0 0 1 48 256 12 3 2 64 64 14 1 3 80 51 7 1 4 96 128 5 3 5 112 73 5 2 6 128 32 4 1 7 144 0 0 0 8 160 0 0 0 9 176 0 0 0 10 192 0 0 0 11 208 0 0 0 12 224 0 0 0 13 240 0 0 0 14 256 16 1 1 15 272 15 9 1 16 288 0 0 0 17 304 0 0 0 18 320 0 0 0 19 336 0 0 0 20 352 0 0 0 21 368 0 0 0 22 384 0 0 0 23 400 0 0 0 24 416 0 0 0 25 432 0 0 0 26 448 0 0 0 27 464 0 0 0 28 480 0 0 0 29 496 33 1 4 30 512 0 0 0 31 528 0 0 0 32 544 0 0 0 33 560 0 0 0 34 576 0 0 0 35 592 0 0 0 36 608 0 0 0 37 624 0 0 0 38 640 0 0 0 40 672 0 0 0 42 704 0 0 0 43 720 17 1 3 44 736 0 0 0 46 768 0 0 0 49 816 0 0 0 51 848 0 0 0 52 864 14 1 3 54 896 0 0 0 57 944 13 1 3 58 960 0 0 0 62 1024 4 1 1 66 1088 15 2 4 67 1104 0 0 0 71 1168 0 0 0 74 1216 0 0 0 76 1248 0 0 0 83 1360 3 1 1 91 1488 11 1 4 94 1536 0 0 0 100 1632 5 1 2 107 1744 0 0 0 111 1808 9 1 4 126 2048 4 4 2 144 2336 7 3 4 151 2448 0 0 0 168 2720 15 15 10 190 3072 28 27 21 202 3264 0 0 0 254 4096 36209 36209 36209 Total 37022 36326 36288 We can calculate the overall fragentation by the last line: Total 37022 36326 36288 (37022 - 36326) / 37022 = 1.87% Also by analysing objects alocated in every class we know why we got so low fragmentation: Most of the allocated objects is in <class 254>. And there is only 1 page in class 254 zspage. So, No fragmentation will be introduced by allocating objs in class 254. And in future, we can collect other zsmalloc statistics as we need and analyse them. Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com> Suggested-by: Minchan Kim <minchan@kernel.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ganesh Mahendran authored
Currently the underlay of zpool: zsmalloc/zbud, do not know who creates them. There is not a method to let zsmalloc/zbud find which caller they belong to. Now we want to add statistics collection in zsmalloc. We need to name the debugfs dir for each pool created. The way suggested by Minchan Kim is to use a name passed by caller(such as zram) to create the zsmalloc pool. /sys/kernel/debug/zsmalloc/zram0 This patch adds an argument `name' to zs_create_pool() and other related functions. Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sergey Senozhatsky authored
`struct zram' contains both `struct gendisk' and `struct request_queue'. the latter can be deleted, because zram->disk carries ->queue pointer, and ->queue carries zram pointer: create_device() zram->queue->queuedata = zram zram->disk->queue = zram->queue zram->disk->private_data = zram so zram->queue is not needed, we can access all necessary data anyway. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Minchan Kim authored
Admin could reset zram during I/O operation going on so we have used zram->init_lock as read-side lock in I/O path to prevent sudden zram meta freeing. However, the init_lock is really troublesome. We can't do call zram_meta_alloc under init_lock due to lockdep splat because zram_rw_page is one of the function under reclaim path and hold it as read_lock while other places in process context hold it as write_lock. So, we have used allocation out of the lock to avoid lockdep warn but it's not good for readability and fainally, I met another lockdep splat between init_lock and cpu_hotplug from kmem_cache_destroy during working zsmalloc compaction. :( Yes, the ideal is to remove horrible init_lock of zram in rw path. This patch removes it in rw path and instead, add atomic refcount for meta lifetime management and completion to free meta in process context. It's important to free meta in process context because some of resource destruction needs mutex lock, which could be held if we releases the resource in reclaim context so it's deadlock, again. As a bonus, we could remove init_done check in rw path because zram_meta_get will do a role for it, instead. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Ganesh Mahendran <opensource.ganesh@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Minchan Kim authored
bd_holders is increased only when user open the device file as FMODE_EXCL so if something opens zram0 as !FMODE_EXCL and request I/O while another user reset zram0, we can see following warning. zram0: detected capacity change from 0 to 64424509440 Buffer I/O error on dev zram0, logical block 180823, lost async page write Buffer I/O error on dev zram0, logical block 180824, lost async page write Buffer I/O error on dev zram0, logical block 180825, lost async page write Buffer I/O error on dev zram0, logical block 180826, lost async page write Buffer I/O error on dev zram0, logical block 180827, lost async page write Buffer I/O error on dev zram0, logical block 180828, lost async page write Buffer I/O error on dev zram0, logical block 180829, lost async page write Buffer I/O error on dev zram0, logical block 180830, lost async page write Buffer I/O error on dev zram0, logical block 180831, lost async page write Buffer I/O error on dev zram0, logical block 180832, lost async page write ------------[ cut here ]------------ WARNING: CPU: 11 PID: 1996 at fs/block_dev.c:57 __blkdev_put+0x1d7/0x210() Modules linked in: CPU: 11 PID: 1996 Comm: dd Not tainted 3.19.0-rc6-next-20150202+ #1125 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x45/0x57 warn_slowpath_common+0x8a/0xc0 warn_slowpath_null+0x1a/0x20 __blkdev_put+0x1d7/0x210 blkdev_put+0x50/0x130 blkdev_close+0x25/0x30 __fput+0xdf/0x1e0 ____fput+0xe/0x10 task_work_run+0xa7/0xe0 do_notify_resume+0x49/0x60 int_signal+0x12/0x17 ---[ end trace 274fbbc5664827d2 ]--- The warning comes from bdev_write_node in blkdev_put path. static void bdev_write_inode(struct inode *inode) { spin_lock(&inode->i_lock); while (inode->i_state & I_DIRTY) { spin_unlock(&inode->i_lock); WARN_ON_ONCE(write_inode_now(inode, true)); <========= here. spin_lock(&inode->i_lock); } spin_unlock(&inode->i_lock); } The reason is dd process encounters I/O fails due to sudden block device disappear so in filemap_check_errors in __writeback_single_inode returns -EIO. If we check bd_openers instead of bd_holders, we could address the problem. When I see the brd, it already have used it rather than bd_holders so although I'm not a expert of block layer, it seems to be better. I can make following warning with below simple script. In addition, I added msleep(2000) below set_capacity(zram->disk, 0) after applying your patch to make window huge(Kudos to Ganesh!) script: echo $((60<<30)) > /sys/block/zram0/disksize setsid dd if=/dev/zero of=/dev/zram0 & sleep 1 setsid echo 1 > /sys/block/zram0/reset Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Ganesh Mahendran <opensource.ganesh@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sergey Senozhatsky authored
We need to return set_capacity(disk, 0) from reset_store() back to zram_reset_device(), a catch by Ganesh Mahendran. Potentially, we can race set_capacity() calls from init and reset paths. The problem is that zram_reset_device() is also getting called from zram_exit(), which performs operations in misleading reversed order -- we first create_device() and then init it, while zram_exit() perform destroy_device() first and then does zram_reset_device(). This is done to remove sysfs group before we reset device, so we can continue with device reset/destruction not being raced by sysfs attr write (f.e. disksize). Apart from that, destroy_device() releases zram->disk (but we still have ->disk pointer), so we cannot acces zram->disk in later zram_reset_device() call, which may cause additional errors in the future. So, this patch rework and cleanup destroy path. 1) remove several unneeded goto labels in zram_init() 2) factor out zram_init() error path and zram_exit() into destroy_devices() function, which takes the number of devices to destroy as its argument. 3) remove sysfs group in destroy_devices() first, so we can reorder operations -- reset device (as expected) goes before disk destroy and queue cleanup. So we can always access ->disk in zram_reset_device(). 4) and, finally, return set_capacity() back under ->init_lock. [akpm@linux-foundation.org: tweak comment] Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Ganesh Mahendran <opensource.ganesh@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sergey Senozhatsky authored
Ganesh Mahendran was the first one who proposed to use bdev->bd_mutex to avoid ->bd_holders race condition: CPU0 CPU1 umount /* zram->init_done is true */ reset_store() bdev->bd_holders == 0 mount ... zram_make_request() zram_reset_device() However, his solution required some considerable amount of code movement, which we can avoid. Apart from using bdev->bd_mutex in reset_store(), this patch also simplifies zram_reset_device(). zram_reset_device() has a bool parameter reset_capacity which tells it whether disk capacity and itself disk should be reset. There are two zram_reset_device() callers: -- zram_exit() passes reset_capacity=false -- reset_store() passes reset_capacity=true So we can move reset_capacity-sensitive work out of zram_reset_device() and perform it unconditionally in reset_store(). This also lets us drop reset_capacity parameter from zram_reset_device() and pass zram pointer only. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Ganesh Mahendran <opensource.ganesh@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ganesh Mahendran authored
zram_meta_alloc() and zram_meta_free() are a pair. In zram_meta_alloc(), meta table is allocated. So it it better to free it in zram_meta_free(). Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sergey Senozhatsky authored
A trivial cleanup of zram_meta_alloc() error handling. Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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