On Wed, Aug 18, 2010 at 12:19:51PM +0530, Nikanth Karthikesan wrote: > On Wednesday 18 August 2010 11:22:53 Balbir Singh wrote: > > * Nikanth Karthikesan <knikanth@xxxxxxx> [2010-08-18 10:23:41]: > > > 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"); > > > > Why not show the Locked as kB as well? I know that the entire VMA is > > locked, but ideally if we can show mss.pss as locked, one can write > > a simple script to accumulate locked memory for the process. NOTE: > > One could choose RSS or PSS, but I'd prefer PSS (even though the > > value is not stable across the system) since it is more accurate > > representation of the truly locked memory. > > > > Agreed. Attached patch does this, i.e, uses PSS as amount of locked memory. Maybe it's only me, but I as an end user instinctively take "Locked" as the plain number of locked pages. How about renaming to "PSSLocked" to avoid such misconceptions? Otherwise Acked-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>