On Tuesday 17 August 2010 21:55:36 Matt Mackall wrote:
> On Tue, 2010-08-17 at 10:39 +0530, Nikanth Karthikesan wrote:
> > Currently there is no way to find whether a process has locked its pages
> > in memory or not. And which of the memory regions are locked in memory.
> >
> > Add a new field to perms field 'l' to export this information. The
> > information exported via maps file is not changed.
>
> I'm worried that your new 'l' flag will fatally surprise some naive
> parser of this file.
>
So how to proceed? Create another "ssmaps" file or something? :) Or is the
following patch any better? Even the "Yes"/"No" could be changed to "0 kB" or
"x kB", if it would make it better.
Thanks
Nikanth
Currently there is no way to find whether a process has locked its pages in
memory or not. And which of the memory regions are locked in memory.
Add a new field "Locked" to export this information via smaps file.
Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>
---
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index a6aca87..6eafd26 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -373,6 +373,7 @@ Referenced: 892 kB
Swap: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
+Locked: No
The first of these lines shows the same information as is displayed for the
mapping in /proc/PID/maps. The remaining lines show the size of the mapping,
@@ -397,6 +398,8 @@ To clear the bits for the file mapped pages associated with the process
> echo 3 > /proc/PID/clear_refs
Any other value written to /proc/PID/clear_refs will have no effect.
+The "Locked" indicates whether the mapping is locked in memory or not.
+
1.2 Kernel data
---------------
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index aea1d3f..7bafbcf 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -405,7 +405,8 @@ static int show_smap(struct seq_file *m, void *v)
"Referenced: %8lu kB\n"
"Swap: %8lu kB\n"
"KernelPageSize: %8lu kB\n"
- "MMUPageSize: %8lu kB\n",
+ "MMUPageSize: %8lu kB\n"
+ "Locked: %s\n",
(vma->vm_end - vma->vm_start) >> 10,
mss.resident >> 10,
(unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
@@ -416,7 +417,8 @@ static int show_smap(struct seq_file *m, void *v)
mss.referenced >> 10,
mss.swap >> 10,
vma_kernel_pagesize(vma) >> 10,
- vma_mmu_pagesize(vma) >> 10);
+ vma_mmu_pagesize(vma) >> 10,
+ (vma->vm_flags & VM_LOCKED) ? "Yes" : "No");
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;
--
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