On Thu, 2010-08-19 at 17:25 -0700, Andrew Morton wrote: > On Wed, 18 Aug 2010 12:19:51 +0530 > Nikanth Karthikesan <knikanth@xxxxxxx> 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 "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..17b0ae0 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: 374 kB > > > > 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..58e586c 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: %8lu kB\n", > > (vma->vm_end - vma->vm_start) >> 10, > > mss.resident >> 10, > > (unsigned long)(mss.pss >> (10 + PSS_SHIFT)), > > @@ -416,7 +417,9 @@ 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) ? > > + (unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0); > > What was the rationale for duplicating the Pss value here, rather than > say Rss or whatever? Really, the value is just a boolean due to kernel > internal details but we should try to put something sensible and > meaningful in there if it isn't just "1" or "0". As it stands, people > will look at the /proc/pid/smaps output, then at proc.txt and will come > away all confused. I think RSS is perhaps a better answer here. > btw, we forgot to document Pss (of all things!) in > Documentation/filesystems/proc.txt. There is something there, but it's nearly useless. How about something like this: Improve smaps field documentation Signed-off-by: Matt Mackall <mpm@xxxxxxxxxxx> diff -r ef46bace13e0 Documentation/filesystems/proc.txt --- a/Documentation/filesystems/proc.txt Wed Aug 18 15:45:23 2010 -0700 +++ b/Documentation/filesystems/proc.txt Fri Aug 20 16:55:09 2010 -0500 @@ -374,13 +374,14 @@ KernelPageSize: 4 kB MMUPageSize: 4 kB -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, -the amount of the mapping that is currently resident in RAM, the "proportional -set size” (divide each shared page by the number of processes sharing it), the -number of clean and dirty shared pages in the mapping, and the number of clean -and dirty private pages in the mapping. The "Referenced" indicates the amount -of memory currently marked as referenced or accessed. +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 (size), the amount of the mapping that is currently +resident in RAM (RSS), the process' proportional share of this mapping +(PSS), the number of clean and dirty shared pages in the mapping, and +the number of clean and dirty private pages in the mapping. The +"Referenced" indicates the amount of memory currently marked as +referenced or accessed. This file is only present if the CONFIG_MMU kernel configuration option is enabled. -- Mathematics is the supreme nostalgia of our time. -- 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>