Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: [PATCH] Provide an interface to limit total page cache. | Date | Thu, 18 Jan 2007 00:56:05 -0700 |
| |
"Roy Huang" <royhuang9@gmail.com> writes:
> A patch provide a interface to limit total page cache in > /proc/sys/vm/pagecache_ratio. The default value is 90 percent. Any > feedback is appreciated.
Anything except a default value of 100% will change the behavior and probably reduce the performance on most systems.
> -Roy > > diff -urp a/include/linux/sysctl.h b/include/linux/sysctl.h > --- a/include/linux/sysctl.h 2007-01-15 17:18:46.000000000 +0800 > +++ b/include/linux/sysctl.h 2007-01-15 17:03:09.000000000 +0800 > @@ -202,6 +202,7 @@ enum > VM_PANIC_ON_OOM=33, /* panic at out-of-memory */ > VM_VDSO_ENABLED=34, /* map VDSO into new processes? */ > VM_MIN_SLAB=35, /* Percent pages ignored by zone reclaim */ > + VM_PAGECACHE_RATIO=36, /* Percent memory is used as page cache */ > }; > > > diff -urp a/kernel/sysctl.c b/kernel/sysctl.c > --- a/kernel/sysctl.c 2007-01-15 17:18:46.000000000 +0800 > +++ b/kernel/sysctl.c 2007-01-15 17:03:09.000000000 +0800 > @@ -1035,6 +1035,15 @@ static ctl_table vm_table[] = { > .extra1 = &zero, > }, > #endif > + { > + .ctl_name = VM_PAGECACHE_RATIO, > + .procname = "pagecache_ratio", > + .data = &pagecache_ratio, > + .maxlen = sizeof(pagecache_ratio), > + .mode = 0644, > + .proc_handler = &pagecache_ratio_sysctl_handler, > + .strategy = &sysctl_intvec, > + }, > { .ctl_name = 0 } > };
This is broken.
You have allocated a binary number for use with sys_sysctl but did not test it.
If you need a special proc_handler to take action when the value is changed you need a special strategy routine.
So since you aren't going to test the binary interface and don't care about it please don't allocate a number for it and just use CTL_UNNUMBERED.
And of course please read the top of linux/sysctl.h
Thank you.
Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |