1. 09 Nov, 2009 5 commits
  2. 13 Oct, 2009 1 commit
  3. 09 Nov, 2009 1 commit
    • Oleg Nesterov's avatar
      Thanks to Roland who pointed out de_thread() issues. · 86370047
      Oleg Nesterov authored
      Currently we add sub-threads to ->real_parent->children list.  This buys
      nothing but slows down do_wait().
      
      With this patch ->children contains only main threads (group leaders). 
      The only complication is that forget_original_parent() should iterate over
      sub-threads by hand, and de_thread() needs another list_replace() when it
      changes ->group_leader.
      
      Henceforth do_wait_thread() can never see task_detached() && !EXIT_DEAD
      tasks, we can remove this check (and we can unify do_wait_thread() and
      ptrace_do_wait()).
      
      This change can confuse the optimistic search in mm_update_next_owner(),
      but this is fixable and minor.
      
      Perhaps badness() and oom_kill_process() should be updated, but they
      should be fixed in any case.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Cc: Roland McGrath <roland@redhat.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Ratan Nalumasu <rnalumasu@gmail.com>
      Cc: Vitaly Mayatskikh <vmayatsk@redhat.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      86370047
  4. 30 Oct, 2009 1 commit
  5. 16 Oct, 2009 3 commits
  6. 11 Nov, 2009 1 commit
  7. 12 Nov, 2009 5 commits
    • Oleg Nesterov's avatar
      Suggested by Roland. · e9fb74f5
      Oleg Nesterov authored
      Unlike powepc, x86 always calls tracehook_report_syscall_exit(step) with
      step = 0, and sends the trap by hand.
      
      This results in unnecessary SIGTRAP when PTRACE_SINGLESTEP follows the
      syscall-exit stop.
      
      Change syscall_trace_leave() to pass the correct "step" argument to
      tracehook and remove the send_sigtrap() logic.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: <linux-arch@vger.kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      e9fb74f5
    • Oleg Nesterov's avatar
      Suggested by Roland. · 8c1fda69
      Oleg Nesterov authored
      Implement user_single_step_siginfo() for x86.  Extract this code from
      send_sigtrap().
      
      Since x86 calls tracehook_report_syscall_exit(step => 0) the new helper is
      not used yet.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: <linux-arch@vger.kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      8c1fda69
    • Oleg Nesterov's avatar
      Suggested by Roland. · 57ef3511
      Oleg Nesterov authored
      Change tracehook_report_syscall_exit() to look at step flag and send the
      trap signal if needed.
      
      This change affects ia64, microblaze, parisc, powerpc, sh.  They pass
      nonzero "step" argument to tracehook but since it was ignored the tracee
      reports via ptrace_notify(), this is not right and not consistent.
      
      	- PTRACE_SETSIGINFO doesn't work
      
      	- if the tracer resumes the tracee with signr != 0 the new signal
      	  is generated rather than delivering it
      
      	- If PT_TRACESYSGOOD is set the tracee reports the wrong exit_code
      
      I don't have a powerpc machine, but I think this test-case should see the
      difference:
      
      	#include <unistd.h>
      	#include <sys/ptrace.h>
      	#include <sys/wait.h>
      	#include <assert.h>
      	#include <stdio.h>
      
      	int main(void)
      	{
      		int pid, status;
      
      		if (!(pid = fork())) {
      			assert(ptrace(PTRACE_TRACEME) == 0);
      			kill(getpid(), SIGSTOP);
      
      			getppid();
      
      			return 0;
      		}
      
      		assert(pid == wait(&status));
      		assert(ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD) == 0);
      
      		assert(ptrace(PTRACE_SYSCALL, pid, 0,0) == 0);
      		assert(pid == wait(&status));
      
      		assert(ptrace(PTRACE_SINGLESTEP, pid, 0,0) == 0);
      		assert(pid == wait(&status));
      
      		if (status == 0x57F)
      			return 0;
      
      		printf("kernel bug: status=%X shouldn't have 0x80\n", status);
      		return 1;
      	}
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: <linux-arch@vger.kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      57ef3511
    • Oleg Nesterov's avatar
      Suggested by Roland. · 237c61f2
      Oleg Nesterov authored
      Implement user_single_step_siginfo() for powerpc.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: <linux-arch@vger.kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      237c61f2
    • Oleg Nesterov's avatar
      Suggested by Roland. · f0b97703
      Oleg Nesterov authored
      Currently there is no way to synthesize a single-stepping trap in the
      arch-independent manner.  This patch adds the default helper which fills
      siginfo_t, arch/ can can override it.
      
      Architetures which implement user_enable_single_step() should add
      user_single_step_siginfo() also.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: <linux-arch@vger.kernel.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      f0b97703
  8. 11 Nov, 2009 1 commit
    • Oleg Nesterov's avatar
      If the tracee calls fork() after PTRACE_SINGLESTEP, the forked child · ee205f64
      Oleg Nesterov authored
      starts with TIF_SINGLESTEP/X86_EFLAGS_TF bits copied from ptraced parent. 
      This is not right, especially when the new child is not auto-attaced: in
      this case it is killed by SIGTRAP.
      
      Change copy_process() to call user_disable_single_step(). Tested on x86.
      
      Test-case:
      
      	#include <stdio.h>
      	#include <unistd.h>
      	#include <signal.h>
      	#include <sys/ptrace.h>
      	#include <sys/wait.h>
      	#include <assert.h>
      
      	int main(void)
      	{
      		int pid, status;
      
      		if (!(pid = fork())) {
      			assert(ptrace(PTRACE_TRACEME) == 0);
      			kill(getpid(), SIGSTOP);
      
      			if (!fork()) {
      				/* kernel bug: this child will be killed by SIGTRAP */
      				printf("Hello world\n");
      				return 43;
      			}
      
      			wait(&status);
      			return WEXITSTATUS(status);
      		}
      
      		for (;;) {
      			assert(pid == wait(&status));
      			if (WIFEXITED(status))
      				break;
      			assert(ptrace(PTRACE_SINGLESTEP, pid, 0,0) == 0);
      		}
      
      		assert(WEXITSTATUS(status) == 43);
      		return 0;
      	}
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarRoland McGrath <roland@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      ee205f64
  9. 30 Oct, 2009 1 commit
  10. 12 Nov, 2009 3 commits
  11. 09 Nov, 2009 1 commit
  12. 16 Oct, 2009 1 commit
  13. 10 Oct, 2009 2 commits
    • Andrew Morton's avatar
      tweak comments · 085eb3ce
      Andrew Morton authored
      Cc: Balbir Singh <balbir@in.ibm.com>
      Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      085eb3ce
    • KAMEZAWA Hiroyuki's avatar
      This is a patch for coalescing access to res_counter at charging by percpu · 7c97f8db
      KAMEZAWA Hiroyuki authored
      caching.  At charge, memcg charges 64pages and remember it in percpu
      cache.  Because it's cache, drain/flush if necessary.
      
      This version uses public percpu area.
       2 benefits for using public percpu area.
       1. Sum of stocked charge in the system is limited to # of cpus
          not to the number of memcg. This shows better synchonization.
       2. drain code for flush/cpuhotplug is very easy (and quick)
      
      The most important point of this patch is that we never touch res_counter
      in fast path. The res_counter is system-wide shared counter which is modified
      very frequently. We shouldn't touch it as far as we can for avoiding
      false sharing.
      
      On x86-64 8cpu server, I tested overheads of memcg at page fault by
      running a program which does map/fault/unmap in a loop. Running
      a task per a cpu by taskset and see sum of the number of page faults
      in 60secs.
      
      [without memcg config]
        40156968  page-faults              #      0.085 M/sec   ( +-   0.046% )
        27.67 cache-miss/faults
      
      [root cgroup]
        36659599  page-faults              #      0.077 M/sec   ( +-   0.247% )
        31.58 cache miss/faults
      
      [in a child cgroup]
        18444157  page-faults              #      0.039 M/sec   ( +-   0.133% )
        69.96 cache miss/faults
      
      [ + coalescing uncharge patch]
        27133719  page-faults              #      0.057 M/sec   ( +-   0.155% )
        47.16 cache miss/faults
      
      [ + coalescing uncharge patch + this patch ]
        34224709  page-faults              #      0.072 M/sec   ( +-   0.173% )
        34.69 cache miss/faults
      
      Changelog (since Oct/2):
        - updated comments
        - replaced get_cpu_var() with __get_cpu_var() if possible.
        - removed mutex for system-wide drain. adds a counter instead of it.
        - removed CONFIG_HOTPLUG_CPU
      
      Changelog (old):
        - rebased onto the latest mmotm
        - moved charge size check before __GFP_WAIT check for avoiding unnecesary
        - added asynchronous flush routine.
        - fixed bugs pointed out by Nishimura-san.
      Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Balbir Singh <balbir@in.ibm.com>
      Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      7c97f8db
  14. 09 Nov, 2009 1 commit
    • KAMEZAWA Hiroyuki's avatar
      In massive parallel enviroment, res_counter can be a performance · a6404ad7
      KAMEZAWA Hiroyuki authored
      bottleneck.  One strong techinque to reduce lock contention is reducing
      calls by coalescing some amount of calls into one.
      
      Considering charge/uncharge chatacteristic,
      	- charge is done one by one via demand-paging.
      	- uncharge is done by
      		- in chunk at munmap, truncate, exit, execve...
      		- one by one via vmscan/paging.
      
      It seems we have a chance to coalesce uncharges for improving scalability
      at unmap/truncation.
      
      This patch is a for coalescing uncharge.  For avoiding scattering memcg's
      structure to functions under /mm, this patch adds memcg batch uncharge
      information to the task.  A reason for per-task batching is for making use
      of caller's context information.  We do batched uncharge (deleyed
      uncharge) when truncation/unmap occurs but do direct uncharge when
      uncharge is called by memory reclaim (vmscan.c).
      
      The degree of coalescing depends on callers
        - at invalidate/trucate... pagevec size
        - at unmap ....ZAP_BLOCK_SIZE
      (memory itself will be freed in this degree.)
      Then, we'll not coalescing too much.
      
      On x86-64 8cpu server, I tested overheads of memcg at page fault by
      running a program which does map/fault/unmap in a loop. Running
      a task per a cpu by taskset and see sum of the number of page faults
      in 60secs.
      
      [without memcg config]
        40156968  page-faults              #      0.085 M/sec   ( +-   0.046% )
        27.67 cache-miss/faults
      [root cgroup]
        36659599  page-faults              #      0.077 M/sec   ( +-   0.247% )
        31.58 miss/faults
      [in a child cgroup]
        18444157  page-faults              #      0.039 M/sec   ( +-   0.133% )
        69.96 miss/faults
      [child with this patch]
        27133719  page-faults              #      0.057 M/sec   ( +-   0.155% )
        47.16 miss/faults
      
      We can see some amounts of improvement.
      (root cgroup doesn't affected by this patch)
      Another patch for "charge" will follow this and above will be improved more.
      
      Changelog(since 2009/10/02):
       - renamed filed of memcg_batch (as pages to bytes, memsw to memsw_bytes)
       - some clean up and commentary/description updates.
       - added initialize code to copy_process(). (possible bug fix)
      
      Changelog(old):
       - fixed !CONFIG_MEM_CGROUP case.
       - rebased onto the latest mmotm + softlimit fix patches.
       - unified patch for callers
       - added commetns.
       - make ->do_batch as bool.
       - removed css_get() at el. We don't need it.
      Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Balbir Singh <balbir@in.ibm.com>
      Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      a6404ad7
  15. 10 Nov, 2009 1 commit
  16. 03 Nov, 2009 1 commit
  17. 25 Sep, 2009 1 commit
  18. 13 Nov, 2009 1 commit
  19. 09 Nov, 2009 1 commit
  20. 09 Oct, 2009 1 commit
  21. 09 Nov, 2009 1 commit
  22. 10 Nov, 2009 2 commits
  23. 25 Sep, 2009 1 commit
  24. 21 Nov, 2008 1 commit
    • Warren Turkal's avatar
      This is a patchset to change the way that the HFS+ filesystem detects · 0c0a4135
      Warren Turkal authored
      whether a volume has a journal or not.
      
      The code currently mounts an HFS+ volume read-only by default when a
      journal is detected.  One can force a read/write mount by giving the
      "force" mount option.  The current code has this behavior since there is
      no support for the HFS+ journal.
      
      My problem is that the detection of the journal could be better.  The
      current code tests the attribute bit in the volume header that indicates
      there is a journal.  If that bit is set, the code assumes that there is a
      journal.
      
      Unfortunately, this is not enough to really determine if there is a
      journal or not.  When that bit is set, one must also examine the journal
      info block field of the volume header.  If this field is 0, there is no
      journal, and the volume can be mounted read/write.
      
      
      This patch:
      
      The HFS+ support in the kernel currently will mount an HFS+ volume
      read-only if the volume header has the attribute bit set that indicates
      there is a journal.  The kernel does this because there is no support for
      a journalled HFS+ volume.
      
      The problem is that this is only half of what needs to be checked to see
      if there really is a journal.  There is also an entry in the volume header
      that tells you where to find the journal info block.  In the kernel
      version of the kernel, this 4 byte block is labeled reserved.  This patch
      identifies the journal info block in the header.
      Signed-off-by: default avatarWarren Turkal <wt@penguintechs.org>
      Cc: Roman Zippel <zippel@linux-m68k.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      0c0a4135
  25. 03 Nov, 2009 2 commits