From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Emelyanov Subject: Re: [PATCH 1/3] posix timers: Allocate timer id per process Date: Fri, 15 Feb 2013 09:13:19 +0400 Message-ID: <511DC3EF.60904@parallels.com> References: <511D0E50.7090505@parallels.com> <511D0E77.2090907@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sasha Levin Cc: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Michael Kerrisk , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux Kernel Mailing List List-Id: linux-api@vger.kernel.org On 02/15/2013 12:13 AM, Sasha Levin wrote: > On Thu, Feb 14, 2013 at 11:19 AM, Pavel Emelyanov wrote: >> From: Stanislav Kinsbursky >> >> Patch replaces global idr with global hash table for posix timers and >> makes timer ids unique not globally, but per process. Next free timer id is >> type of integer and stored on signal struct (posix_timer_id). If free timer >> id reaches negative value on timer creation, it will be dropped to zero and >> -EAGAIN will be returned to user. >> >> Hash table has 512 slots. >> Key is constructed as follows: >> key = hash_32(hash_32(current->signal) ^ posix_timer_id)); >> >> Note: with this patch, id, returned to user, is not the minimal free >> amymore. It means, that id, returned to user space in loop, listed below, will >> be increasing on each iteration till INT_MAX and then dropped to zero: >> >> while(1) { >> id = timer_create(...); >> timer_delete(id); >> } >> >> Signed-off-by: Stanislav Kinsbursky >> Signed-off-by: Pavel Emelyanov > > Hi Pavel, > > Why not use linux/hashtable.h? Simply because this patch was just picked from the previous discussions as is :) I will tune it to use hashtable.h in the next iteration. > > Thanks, > Sasha > . >