// $Header$
// Kernel Version:
// VERSION = 2
// PATCHLEVEL = 5
// SUBLEVEL = 1
// EXTRAVERSION =
--- 2.5/arch/i386/kernel/process.c Thu Oct 11 15:19:41 2001
+++ build-2.5/arch/i386/kernel/process.c Thu Dec 13 21:04:36 2001
@@ -465,23 +465,6 @@
}
/*
- * No need to lock the MM as we are the last user
- */
-void release_segments(struct mm_struct *mm)
-{
- void * ldt = mm->context.segments;
-
- /*
- * free the LDT
- */
- if (ldt) {
- mm->context.segments = NULL;
- clear_LDT();
- vfree(ldt);
- }
-}
-
-/*
* Create a kernel thread
*/
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
@@ -533,40 +516,15 @@
void release_thread(struct task_struct *dead_task)
{
if (dead_task->mm) {
- void * ldt = dead_task->mm->context.segments;
-
// temporary debugging check
- if (ldt) {
- printk("WARNING: dead process %8s still has LDT? <%p>\n",
- dead_task->comm, ldt);
+ if (dead_task->mm->context.size) {
+ printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
+ dead_task->comm,
+ dead_task->mm->context.ldt,
+ dead_task->mm->context.size);
BUG();
}
}
-}
-
-/*
- * we do not have to muck with descriptors here, that is
- * done in switch_mm() as needed.
- */
-void copy_segments(struct task_struct *p, struct mm_struct *new_mm)
-{
- struct mm_struct * old_mm;
- void *old_ldt, *ldt;
-
- ldt = NULL;
- old_mm = current->mm;
- if (old_mm && (old_ldt = old_mm->context.segments) != NULL) {
- /*
- * Completely new LDT, we initialize it from the parent:
- */
- ldt = vmalloc(LDT_ENTRIES*LDT_ENTRY_SIZE);
- if (!ldt)
- printk(KERN_WARNING "ldt allocation failed\n");
- else
- memcpy(ldt, old_ldt, LDT_ENTRIES*LDT_ENTRY_SIZE);
- }
- new_mm->context.segments = ldt;
- new_mm->context.cpuvalid = ~0UL; /* valid on all CPU's - they can't have stale data */
}
/*
--- 2.5/arch/i386/kernel/ldt.c Fri Oct 26 17:02:55 2001
+++ build-2.5/arch/i386/kernel/ldt.c Thu Dec 13 21:19:57 2001
@@ -12,37 +12,137 @@
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/vmalloc.h>
+#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/ldt.h>
#include <asm/desc.h>
+#ifdef CONFIG_SMP /* avoids "defined but not used" warnig */
+static void flush_ldt(void *mm)
+{
+ if (current->mm)
+ load_LDT(¤t->mm->context);
+}
+#endif
+
+static int alloc_ldt(mm_context_t *pc, int mincount, int reload)
+{
+ void *oldldt;
+ void *newldt;
+ int oldsize;
+
+ if (mincount <= pc->size)
+ return 0;
+ oldsize = pc->size;
+ mincount = (mincount+511)&(~511);
+ if (mincount*LDT_ENTRY_SIZE > PAGE_SIZE)
+ newldt = vmalloc(mincount*LDT_ENTRY_SIZE);
+ else
+ newldt = kmalloc(mincount*LDT_ENTRY_SIZE, GFP_KERNEL);
+
+ if (!newldt)
+ return -ENOMEM;
+
+ if (oldsize)
+ memcpy(newldt, pc->ldt, oldsize*LDT_ENTRY_SIZE);
+ oldldt = pc->ldt;
+ memset(newldt+oldsize*LDT_ENTRY_SIZE, 0, (mincount-oldsize)*LDT_ENTRY_SIZE);
+ wmb();
+ pc->ldt = newldt;
+ pc->size = mincount;
+ if (reload) {
+ load_LDT(pc);
+#ifdef CONFIG_SMP
+ if (current->mm->cpu_vm_mask != (1<<smp_processor_id()))
+ smp_call_function(flush_ldt, 0, 1, 1);
+#endif
+ }
+ wmb();
+ if (oldsize) {
+ if (oldsize*LDT_ENTRY_SIZE > PAGE_SIZE)
+ vfree(oldldt);
+ else
+ kfree(oldldt);
+ }
+ return 0;
+}
+
+static inline int copy_ldt(mm_context_t *new, mm_context_t *old)
+{
+ int err = alloc_ldt(new, old->size, 0);
+ if (err < 0) {
+ printk(KERN_WARNING "ldt allocation failed\n");
+ new->size = 0;
+ return err;
+ }
+ memcpy(new->ldt, old->ldt, old->size*LDT_ENTRY_SIZE);
+ return 0;
+}
+
/*
- * read_ldt() is not really atomic - this is not a problem since
- * synchronization of reads and writes done to the LDT has to be
- * assured by user-space anyway. Writes are atomic, to protect
- * the security checks done on new descriptors.
+ * we do not have to muck with descriptors here, that is
+ * done in switch_mm() as needed.
*/
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+ struct mm_struct * old_mm;
+ int retval = 0;
+
+ init_MUTEX(&mm->context.sem);
+ mm->context.size = 0;
+ old_mm = current->mm;
+ if (old_mm && old_mm->context.size > 0) {
+ down(&old_mm->context.sem);
+ retval = copy_ldt(&mm->context, &old_mm->context);
+ up(&old_mm->context.sem);
+ }
+ return retval;
+}
+
+/*
+ * No need to lock the MM as we are the last user
+ */
+void release_segments(struct mm_struct *mm)
+{
+ if (mm->context.size) {
+ clear_LDT();
+ if (mm->context.size*LDT_ENTRY_SIZE > PAGE_SIZE)
+ vfree(mm->context.ldt);
+ else
+ kfree(mm->context.ldt);
+ mm->context.size = 0;
+ }
+}
+
static int read_ldt(void * ptr, unsigned long bytecount)
{
int err;
unsigned long size;
struct mm_struct * mm = current->mm;
- err = 0;
- if (!mm->context.segments)
- goto out;
+ if (!mm->context.size)
+ return 0;
+ if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES)
+ bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES;
- size = LDT_ENTRIES*LDT_ENTRY_SIZE;
+ down(&mm->context.sem);
+ size = mm->context.size*LDT_ENTRY_SIZE;
if (size > bytecount)
size = bytecount;
- err = size;
- if (copy_to_user(ptr, mm->context.segments, size))
+ err = 0;
+ if (copy_to_user(ptr, mm->context.ldt, size))
err = -EFAULT;
-out:
- return err;
+ up(&mm->context.sem);
+ if (err < 0)
+ return err;
+ if (size != bytecount) {
+ /* zero-fill the rest */
+ clear_user(ptr+size, bytecount-size);
+ }
+ return bytecount;
}
static int read_default_ldt(void * ptr, unsigned long bytecount)
@@ -53,7 +153,7 @@
err = 0;
address = &default_ldt[0];
- size = sizeof(struct desc_struct);
+ size = 5*sizeof(struct desc_struct);
if (size > bytecount)
size = bytecount;
@@ -88,24 +188,14 @@
goto out;
}
- /*
- * the GDT index of the LDT is allocated dynamically, and is
- * limited by MAX_LDT_DESCRIPTORS.
- */
- down_write(&mm->mmap_sem);
- if (!mm->context.segments) {
- void * segments = vmalloc(LDT_ENTRIES*LDT_ENTRY_SIZE);
- error = -ENOMEM;
- if (!segments)
+ down(&mm->context.sem);
+ if (ldt_info.entry_number >= mm->context.size) {
+ error = alloc_ldt(¤t->mm->context, ldt_info.entry_number+1, 1);
+ if (error < 0)
goto out_unlock;
- memset(segments, 0, LDT_ENTRIES*LDT_ENTRY_SIZE);
- wmb();
- mm->context.segments = segments;
- mm->context.cpuvalid = 1UL << smp_processor_id();
- load_LDT(mm);
}
- lp = (__u32 *) ((ldt_info.entry_number << 3) + (char *) mm->context.segments);
+ lp = (__u32 *) ((ldt_info.entry_number << 3) + (char *) mm->context.ldt);
/* Allow LDTs to be cleared by the user. */
if (ldt_info.base_addr == 0 && ldt_info.limit == 0) {
@@ -143,7 +233,7 @@
error = 0;
out_unlock:
- up_write(&mm->mmap_sem);
+ up(&mm->context.sem);
out:
return error;
}
--- 2.5/include/asm-i386/mmu.h Sat Aug 11 16:15:27 2001
+++ build-2.5/include/asm-i386/mmu.h Thu Dec 13 21:00:48 2001
@@ -4,10 +4,13 @@
/*
* The i386 doesn't have a mmu context, but
* we put the segment information here.
+ *
+ * cpu_vm_mask is used to optimize ldt flushing.
*/
typedef struct {
- void *segments;
- unsigned long cpuvalid;
+ int size;
+ struct semaphore sem;
+ void * ldt;
} mm_context_t;
#endif
--- 2.5/include/asm-i386/desc.h Sat Aug 11 16:15:27 2001
+++ build-2.5/include/asm-i386/desc.h Thu Dec 13 20:54:47 2001
@@ -79,13 +79,13 @@
/*
* load one particular LDT into the current CPU
*/
-static inline void load_LDT (struct mm_struct *mm)
+static inline void load_LDT (mm_context_t *pc)
{
int cpu = smp_processor_id();
- void *segments = mm->context.segments;
- int count = LDT_ENTRIES;
+ void *segments = pc->ldt;
+ int count = pc->size;
- if (!segments) {
+ if (!count) {
segments = &default_ldt[0];
count = 5;
}
--- 2.5/include/asm-i386/mmu_context.h Sat Aug 11 16:15:27 2001
+++ build-2.5/include/asm-i386/mmu_context.h Thu Dec 13 21:05:49 2001
@@ -10,7 +10,7 @@
* possibly do the LDT unload here?
*/
#define destroy_context(mm) do { } while(0)
-#define init_new_context(tsk,mm) 0
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
#ifdef CONFIG_SMP
@@ -30,19 +30,19 @@
if (prev != next) {
/* stop flush ipis for the previous mm */
clear_bit(cpu, &prev->cpu_vm_mask);
- /*
- * Re-load LDT if necessary
- */
- if (prev->context.segments != next->context.segments)
- load_LDT(next);
#ifdef CONFIG_SMP
cpu_tlbstate[cpu].state = TLBSTATE_OK;
cpu_tlbstate[cpu].active_mm = next;
#endif
set_bit(cpu, &next->cpu_vm_mask);
- set_bit(cpu, &next->context.cpuvalid);
+
/* Re-load page tables */
asm volatile("movl %0,%%cr3": :"r" (__pa(next->pgd)));
+ /* load_LDT, if either the previous or next thread
+ * has a non-default LDT.
+ */
+ if (next->context.size+prev->context.size)
+ load_LDT(&next->context);
}
#ifdef CONFIG_SMP
else {
@@ -54,9 +54,8 @@
* tlb flush IPI delivery. We must flush our tlb.
*/
local_flush_tlb();
+ load_LDT(&next->context);
}
- if (!test_and_set_bit(cpu, &next->context.cpuvalid))
- load_LDT(next);
}
#endif
}
--- 2.5/kernel/fork.c Wed Dec 12 20:20:31 2001
+++ build-2.5/kernel/fork.c Thu Dec 13 20:59:44 2001
@@ -340,11 +340,6 @@
if (retval)
goto free_pt;
- /*
- * child gets a private LDT (if there was an LDT in the parent)
- */
- copy_segments(tsk, mm);
-
if (init_new_context(tsk,mm))
goto free_pt;
--- 2.5/include/asm-i386/processor.h Fri Nov 23 20:35:38 2001
+++ build-2.5/include/asm-i386/processor.h Thu Dec 13 21:05:01 2001
@@ -431,8 +431,7 @@
*/
extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
-/* Copy and release all segment info associated with a VM */
-extern void copy_segments(struct task_struct *p, struct mm_struct * mm);
+/* Release all segment info associated with a VM */
extern void release_segments(struct mm_struct * mm);
/*
Manfred Spraul wrote:
| > Do you have an NTFS disk mounted? I had a similar problem which was
| > "fixed" by not having an NTFS vol mounted. Apparently the ntfs code
| > makes a lot of calls to vmalloc which leads to badness.
| >
| Both modify_ldt and NTFS make lots of calls to vmalloc.
|
| AFAICS this limits the number of concurrently running processes that are
| linked to libpthread to less than 2000 on highmem machines, regardless
| of the actual free memory.
|
| Could you try the attached patch?
| It should permit you to keep the NTFS vol mounted - libpthread doesn't
| need a 64 kB LDT. That should reduce the pressure on the vmalloc area.
|
| The patch applies to both 2.4.16 and 2.5.1
Tried your patch against 2.4.16.
After running updatedb with all my vols mounted (including ntfs) I was
able to start up all applications without trouble, so your patch was
good in that regard. However, ntfs isn't happy. A whole lotta this is
in my syslog:
Dec 17 22:36:55 orf kernel: NTFS: ntfs_getdir_unsorted(): Read failed. Returning error code -95.
Dec 17 22:36:55 orf last message repeated 5 times
Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size = 0x1000) failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_getdir_unsorted(): Read failed. Returning error code -95.
Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size = 0x1000) failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_getdir_unsorted(): Read failed. Returning error code -95.
Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size = 0x1000) failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size = 0x1000) failed
Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
Leigh Orf
At 03:40 18/12/01, Leigh Orf wrote:
>Manfred Spraul wrote:
>| > Do you have an NTFS disk mounted? I had a similar problem which was
>| > "fixed" by not having an NTFS vol mounted. Apparently the ntfs code
>| > makes a lot of calls to vmalloc which leads to badness.
>| >
>| Both modify_ldt and NTFS make lots of calls to vmalloc.
>|
>| AFAICS this limits the number of concurrently running processes that are
>| linked to libpthread to less than 2000 on highmem machines, regardless
>| of the actual free memory.
>|
>| Could you try the attached patch?
>| It should permit you to keep the NTFS vol mounted - libpthread doesn't
>| need a 64 kB LDT. That should reduce the pressure on the vmalloc area.
>|
>| The patch applies to both 2.4.16 and 2.5.1
>
>Tried your patch against 2.4.16.
>
>After running updatedb with all my vols mounted (including ntfs) I was
>able to start up all applications without trouble, so your patch was
>good in that regard. However, ntfs isn't happy. A whole lotta this is
>in my syslog:
Hi,
I am going on holiday for two weeks from tomorrow but when I get back I
will backport the new allocator from ntfs tng to the old ntfs driver. This
only uses vmalloc if necessary so will decrease the number of vmalloc()s
dramatically and hopefully this will make your kernel happier.
I will CC: patch to you so you can see if all your problems go away or if
it is not sufficient.
Best regards,
Anton
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_getdir_unsorted(): Read failed.
>Returning error code -95.
>Dec 17 22:36:55 orf last message repeated 5 times
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size =
>0x1000) failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_getdir_unsorted(): Read failed.
>Returning error code -95.
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size =
>0x1000) failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_getdir_unsorted(): Read failed.
>Returning error code -95.
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size =
>0x1000) failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_insert_run: ntfs_vmalloc(new_size =
>0x1000) failed
>Dec 17 22:36:55 orf kernel: NTFS: ntfs_process_runs: ntfs_insert_run failed
>
>Leigh Orf
>
>-
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--
"I've not lost my mind. It's backed up on tape somewhere." - Unknown
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Linux NTFS Maintainer / WWW: http://linux-ntfs.sf.net/
ICQ: 8561279 / WWW: http://www-stu.christs.cam.ac.uk/~aia21/