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<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>LKML: Paul Jackson: [PATCH 05/10] Cpuset: combine refresh_mems and update_mems</title><link href="/css/message.css" rel="stylesheet" type="text/css" /><link href="/css/wrap.css" rel="alternate stylesheet" type="text/css" title="wrap" /><link href="/css/nowrap.css" rel="stylesheet" type="text/css" title="nowrap" /><link href="/favicon.ico" rel="shortcut icon" /><script src="/js/simple-calendar.js" type="text/javascript"></script><script src="/js/styleswitcher.js" type="text/javascript"></script><link rel="alternate" type="application/rss+xml" title="lkml.org : last 100 messages" href="/rss.php" /><link rel="alternate" type="application/rss+xml" title="lkml.org : last messages by Paul Jackson" href="/groupie.php?aid=5266" /><script> var _paq = window._paq = window._paq || []; /* tracker methods like "setCustomDimension" should be called before "trackPageView" */ _paq.push(["setDoNotTrack", true]); _paq.push(["disableCookies"]); _paq.push(['trackPageView']); _paq.push(['enableLinkTracking']); (function() { var u="//m.lkml.org/"; _paq.push(['setTrackerUrl', u+'matomo.php']); _paq.push(['setSiteId', '1']); var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s); })(); </script></head><body onload="es.jasper.simpleCalendar.init();" itemscope="itemscope" itemtype="http://schema.org/BlogPosting"><table border="0" cellpadding="0" cellspacing="0"><tr><td width="180" align="center"><a href="/"><img style="border:0;width:135px;height:32px" src="/images/toprowlk.gif" alt="lkml.org" /></a></td><td width="32">聽</td><td class="nb"><div><a class="nb" href="/lkml"> [lkml]</a> 聽 <a class="nb" href="/lkml/2005"> [2005]</a> 聽 <a class="nb" href="/lkml/2005/12"> [Dec]</a> 聽 <a class="nb" href="/lkml/2005/12/10"> [10]</a> 聽 <a class="nb" href="/lkml/last100"> [last100]</a> 聽 <a href="/rss.php"><img src="/images/rss-or.gif" border="0" alt="RSS Feed" /></a></div><div>Views: <a href="#" class="nowrap" onclick="setActiveStyleSheet('wrap');return false;">[wrap]</a><a href="#" class="wrap" onclick="setActiveStyleSheet('nowrap');return false;">[no wrap]</a> 聽 <a class="nb" href="/lkml/mheaders/2005/12/10/31" onclick="this.href='/lkml/headers'+'/2005/12/10/31';">[headers]</a>聽 <a href="/lkml/bounce/2005/12/10/31">[forward]</a>聽 </div></td><td width="32">聽</td></tr><tr><td valign="top"><div class="es-jasper-simpleCalendar" baseurl="/lkml/"></div><div class="threadlist">Messages in this thread</div><ul class="threadlist"><li class="root"><a href="/lkml/2005/12/10/28">First message in thread</a></li><li><a href="/lkml/2005/12/10/28">Paul Jackson</a><ul><li><a href="/lkml/2005/12/10/29">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/30">Paul Jackson</a></li><li class="origin"><a href="">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/32">Paul Jackson</a><ul><li><a href="/lkml/2005/12/10/48">Paul Jackson</a></li></ul></li><li><a href="/lkml/2005/12/10/33">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/34">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/35">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/36">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/37">Paul Jackson</a></li><li><a href="/lkml/2005/12/10/39">Paul Jackson</a></li></ul></li></ul><div class="threadlist">Patch in this message</div><ul class="threadlist"><li><a href="/lkml/diff/2005/12/10/31/1">Get diff 1</a></li></ul></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerl.gif" width="32" height="32" alt="/" /></td><td class="c" rowspan="2" valign="top" style="padding-top: 1em"><table><tr><td><table><tr><td class="lp">Date</td><td class="rp" itemprop="datePublished">Sat, 10 Dec 2005 00:19:11 -0800 (PST)</td></tr><tr><td class="lp">From</td><td class="rp" itemprop="author">Paul Jackson <></td></tr><tr><td class="lp">Subject</td><td class="rp" itemprop="name">[PATCH 05/10] Cpuset: combine refresh_mems and update_mems</td></tr></table></td><td></td></tr></table><pre itemprop="articleBody">The important code paths through alloc_pages_current() and alloc_page_vma(), by which most kernel page allocations go, both called cpuset_update_current_mems_allowed(), which in turn called refresh_mems(). -Both- of these latter two routines did a tasklock, got the tasks cpuset pointer, and checked for out of date cpuset->mems_generation. That was a silly duplication of code and waste of CPU cycles on an important code path. Consolidated those two routines into a single routine, called cpuset_update_task_memory_state(), since it updates more than just mems_allowed. Changed all callers of either routine to call the new consolidated routine. Signed-off-by: Paul Jackson <pj@sgi.com> --- include/linux/cpuset.h | 4 +- kernel/cpuset.c | 95 +++++++++++++++++++++---------------------------- mm/mempolicy.c | 10 ++--- 3 files changed, 48 insertions(+), 61 deletions(-) --- 2.6.15-rc3-mm1.orig/include/linux/cpuset.h 2005-12-07 22:00:40.525006978 -0800 +++ 2.6.15-rc3-mm1/include/linux/cpuset.h 2005-12-07 23:48:54.860211028 -0800 @@ -20,7 +20,7 @@ extern void cpuset_fork(struct task_stru extern void cpuset_exit(struct task_struct *p); extern cpumask_t cpuset_cpus_allowed(const struct task_struct *p); void cpuset_init_current_mems_allowed(void); -void cpuset_update_current_mems_allowed(void); +void cpuset_update_task_memory_state(void); #define cpuset_nodes_subset_current_mems_allowed(nodes) \ nodes_subset((nodes), current->mems_allowed) int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl); @@ -51,7 +51,7 @@ static inline cpumask_t cpuset_cpus_allo } static inline void cpuset_init_current_mems_allowed(void) {} -static inline void cpuset_update_current_mems_allowed(void) {} +static inline void cpuset_update_task_memory_state(void) {} #define cpuset_nodes_subset_current_mems_allowed(nodes) (1) static inline int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl) --- 2.6.15-rc3-mm1.orig/kernel/cpuset.c 2005-12-07 22:12:08.509137821 -0800 +++ 2.6.15-rc3-mm1/kernel/cpuset.c 2005-12-07 23:52:21.746290572 -0800 @@ -584,13 +584,26 @@ static void guarantee_online_mems(const BUG_ON(!nodes_intersects(*pmask, node_online_map)); } -/* - * Refresh current tasks mems_allowed and mems_generation from current - * tasks cpuset. +/** + * cpuset_update_task_memory_state - update task memory placement * - * Call without callback_sem or task_lock() held. May be called with - * or without manage_sem held. Will acquire task_lock() and might - * acquire callback_sem during call. + * If the current tasks cpusets mems_allowed changed behind our + * backs, update current->mems_allowed, mems_generation and task NUMA + * mempolicy to the new value. + * + * Task mempolicy is updated by rebinding it relative to the + * current->cpuset if a task has its memory placement changed. + * Do not call this routine if in_interrupt(). + * + * Call without callback_sem or task_lock() held. May be called + * with or without manage_sem held. Except in early boot or + * an exiting task, when tsk->cpuset is NULL, this routine will + * acquire task_lock(). We don't need to use task_lock to guard + * against another task changing a non-NULL cpuset pointer to NULL, + * as that is only done by a task on itself, and if the current task + * is here, it is not simultaneously in the exit code NULL'ing its + * cpuset pointer. This routine also might acquire callback_sem and + * current->mm->mmap_sem during call. * * The task_lock() is required to dereference current->cpuset safely. * Without it, we could pick up the pointer value of current->cpuset @@ -605,32 +618,36 @@ static void guarantee_online_mems(const * task has been modifying its cpuset. */ -static void refresh_mems(void) +void cpuset_update_task_memory_state() { int my_cpusets_mem_gen; + struct task_struct *tsk = current; + struct cpuset *cs = tsk->cpuset; - task_lock(current); - my_cpusets_mem_gen = current->cpuset->mems_generation; - task_unlock(current); + if (unlikely(!cs)) + return; + + task_lock(tsk); + my_cpusets_mem_gen = cs->mems_generation; + task_unlock(tsk); - if (current->cpuset_mems_generation != my_cpusets_mem_gen) { - struct cpuset *cs; - nodemask_t oldmem = current->mems_allowed; + if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) { + nodemask_t oldmem = tsk->mems_allowed; int migrate; down(&callback_sem); - task_lock(current); - cs = current->cpuset; + task_lock(tsk); + cs = tsk->cpuset; /* Maybe changed when task not locked */ migrate = is_memory_migrate(cs); - guarantee_online_mems(cs, &current->mems_allowed); - current->cpuset_mems_generation = cs->mems_generation; - task_unlock(current); + guarantee_online_mems(cs, &tsk->mems_allowed); + tsk->cpuset_mems_generation = cs->mems_generation; + task_unlock(tsk); up(&callback_sem); - if (!nodes_equal(oldmem, current->mems_allowed)) { - numa_policy_rebind(&oldmem, &current->mems_allowed); + numa_policy_rebind(&oldmem, &tsk->mems_allowed); + if (!nodes_equal(oldmem, tsk->mems_allowed)) { if (migrate) { - do_migrate_pages(current->mm, &oldmem, - &current->mems_allowed, + do_migrate_pages(tsk->mm, &oldmem, + &tsk->mems_allowed, MPOL_MF_MOVE_ALL); } } @@ -1630,7 +1647,7 @@ static long cpuset_create(struct cpuset return -ENOMEM; down(&manage_sem); - refresh_mems(); + cpuset_update_task_memory_state(); cs->flags = 0; if (notify_on_release(parent)) set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags); @@ -1688,7 +1705,7 @@ static int cpuset_rmdir(struct inode *un /* the vfs holds both inode->i_sem already */ down(&manage_sem); - refresh_mems(); + cpuset_update_task_memory_state(); if (atomic_read(&cs->count) > 0) { up(&manage_sem); return -EBUSY; @@ -1873,36 +1890,6 @@ void cpuset_init_current_mems_allowed(vo } /** - * cpuset_update_current_mems_allowed - update mems parameters to new values - * - * If the current tasks cpusets mems_allowed changed behind our backs, - * update current->mems_allowed and mems_generation to the new value. - * Do not call this routine if in_interrupt(). - * - * Call without callback_sem or task_lock() held. May be called - * with or without manage_sem held. Unless exiting, it will acquire - * task_lock(). Also might acquire callback_sem during call to - * refresh_mems(). - */ - -void cpuset_update_current_mems_allowed(void) -{ - struct cpuset *cs; - int need_to_refresh = 0; - - task_lock(current); - cs = current->cpuset; - if (!cs) - goto done; - if (current->cpuset_mems_generation != cs->mems_generation) - need_to_refresh = 1; -done: - task_unlock(current); - if (need_to_refresh) - refresh_mems(); -} - -/** * cpuset_zonelist_valid_mems_allowed - check zonelist vs. curremt mems_allowed * @zl: the zonelist to be checked * --- 2.6.15-rc3-mm1.orig/mm/mempolicy.c 2005-12-07 22:00:40.525983551 -0800 +++ 2.6.15-rc3-mm1/mm/mempolicy.c 2005-12-07 23:48:54.994978144 -0800 @@ -389,7 +389,7 @@ static int contextualize_policy(int mode if (!nodes) return 0; - cpuset_update_current_mems_allowed(); + cpuset_update_task_memory_state(); if (!cpuset_nodes_subset_current_mems_allowed(*nodes)) return -EINVAL; return mpol_check_policy(mode, nodes); @@ -463,7 +463,7 @@ long do_get_mempolicy(int *policy, nodem struct vm_area_struct *vma = NULL; struct mempolicy *pol = current->mempolicy; - cpuset_update_current_mems_allowed(); + cpuset_update_task_memory_state(); if (flags & ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR)) return -EINVAL; if (flags & MPOL_F_ADDR) { @@ -1118,7 +1118,7 @@ alloc_page_vma(gfp_t gfp, struct vm_area { struct mempolicy *pol = get_vma_policy(current, vma, addr); - cpuset_update_current_mems_allowed(); + cpuset_update_task_memory_state(); if (unlikely(pol->policy == MPOL_INTERLEAVE)) { unsigned nid; @@ -1144,7 +1144,7 @@ alloc_page_vma(gfp_t gfp, struct vm_area * interrupt context and apply the current process NUMA policy. * Returns NULL when no page can be allocated. * - * Don't call cpuset_update_current_mems_allowed() unless + * Don't call cpuset_update_task_memory_state() unless * 1) it's ok to take cpuset_sem (can WAIT), and * 2) allocating for current task (not interrupt). */ @@ -1153,7 +1153,7 @@ struct page *alloc_pages_current(gfp_t g struct mempolicy *pol = current->mempolicy; if ((gfp & __GFP_WAIT) && !in_interrupt()) - cpuset_update_current_mems_allowed(); + cpuset_update_task_memory_state(); if (!pol || in_interrupt()) pol = &default_policy; if (pol->policy == MPOL_INTERLEAVE) -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson <pj@sgi.com> 1.650.933.1373 - 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 <a href="http://vger.kernel.org/majordomo-info.html">http://vger.kernel.org/majordomo-info.html</a> Please read the FAQ at <a href="http://www.tux.org/lkml/">http://www.tux.org/lkml/</a> </pre></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerr.gif" width="32" height="32" alt="\" /></td></tr><tr><td align="right" valign="bottom"> 聽 </td></tr><tr><td align="right" valign="bottom">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerl.gif" width="32" height="32" alt="\" /></td><td class="c">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerr.gif" width="32" height="32" alt="/" /></td></tr><tr><td align="right" valign="top" colspan="2"> 聽 </td><td class="lm">Last update: 2005-12-10 09:22 聽聽 [from the cache] 漏2003-2020 <a href="http://blog.jasper.es/">Jasper Spaans</a>|hosted at <a href="https://www.digitalocean.com/?refcode=9a8e99d24cf9">Digital Ocean</a> and my Meterkast|<a href="http://blog.jasper.es/categories.html#lkml-ref">Read the blog</a></td><td>聽</td></tr></table><script language="javascript" src="/js/styleswitcher.js" type="text/javascript"></script></body></html>