linux-kernel - Re: [Patch] Scale pidhash_shift/pidhash_size up based on num_possible

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20080731200835.GK9663@sgi.com>
Date:	Thu, 31 Jul 2008 15:08:35 -0500
From:	Robin Holt <holt@....com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	Robin Holt <holt@....com>, linux-kernel@...r.kernel.org,
	Pavel Emelyanov <xemul@...nvz.org>,
	Oleg Nesterov <oleg@...sign.ru>,
	Sukadev Bhattiprolu <sukadev@...ibm.com>,
	Paul Menage <menage@...gle.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [Patch] Scale pidhash_shift/pidhash_size up based on
	num_possible_cpus().

Like so???

I have not tested this yet.

---

Set the upper limit for the pidhash_shift based upon PID_MAX_LIMIT.

Signed-off-by: Robin Holt <holt@....com>


Index: contention_unroll/kernel/pid.c
===================================================================
--- contention_unroll.orig/kernel/pid.c	2008-07-31 11:59:21.154284073 -0500
+++ contention_unroll/kernel/pid.c	2008-07-31 15:07:21.909158788 -0500
@@ -504,7 +504,7 @@ void __init pidhash_init(void)
 	unsigned long megabytes = nr_kernel_pages >> (20 - PAGE_SHIFT);
 
 	pidhash_shift = max(4, fls(megabytes * 4));
-	pidhash_shift = min(12, pidhash_shift);
+	pidhash_shift = min(fls(PID_MAX_LIMIT) - 6, pidhash_shift);
 	pidhash_size = 1 << pidhash_shift;
 
 	printk("PID hash table entries: %d (order: %d, %Zd bytes)\n",
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/