From 9276b1bc96a132f4068fdee00983c532f43d3a26 Mon Sep 17 00:00:00 2001 From: Paul Jackson Date: Wed, 6 Dec 2006 20:31:48 -0800 Subject: [PATCH] memory page_alloc zonelist caching speedup Optimize the critical zonelist scanning for free pages in the kernel memory allocator by caching the zones that were found to be full recently, and skipping them. Remembers the zones in a zonelist that were short of free memory in the last second. And it stashes a zone-to-node table in the zonelist struct, to optimize that conversion (minimize its cache footprint.) Recent changes: This differs in a significant way from a similar patch that I posted a week ago. Now, instead of having a nodemask_t of recently full nodes, I have a bitmask of recently full zones. This solves a problem that last weeks patch had, which on systems with multiple zones per node (such as DMA zone) would take seeing any of these zones full as meaning that all zones on that node were full. Also I changed names - from "zonelist faster" to "zonelist cache", as that seemed to better convey what we're doing here - caching some of the key zonelist state (for faster access.) See below for some performance benchmark results. After all that discussion with David on why I didn't need them, I went and got some ;). I wanted to verify that I had not hurt the normal case of memory allocation noticeably. At least for my one little microbenchmark, I found (1) the normal case wasn't affected, and (2) workloads that forced scanning across multiple nodes for memory improved up to 10% fewer System CPU cycles and lower elapsed clock time ('sys' and 'real'). Good. See details, below. I didn't have the logic in get_page_from_freelist() for various full nodes and zone reclaim failures correct. That should be fixed up now - notice the new goto labels zonelist_scan, this_zone_full, and try_next_zone, in get_page_from_freelist(). There are two reasons I persued this alternative, over some earlier proposals that would have focused on optimizing the fake numa emulation case by caching the last useful zone: 1) Contrary to what I said before, we (SGI, on large ia64 sn2 systems) have seen real customer loads where the cost to scan the zonelist was a problem, due to many nodes being full of memory before we got to a node we could use. Or at least, I think we have. This was related to me by another engineer, based on experiences from some time past. So this is not guaranteed. Most likely, though. The following approach should help such real numa systems just as much as it helps fake numa systems, or any combination thereof. 2) The effort to distinguish fake from real numa, using node_distance, so that we could cache a fake numa node and optimize choosing it over equivalent distance fake nodes, while continuing to properly scan all real nodes in distance order, was going to require a nasty blob of zonelist and node distance munging. The following approach has no new dependency on node distances or zone sorting. See comment in the patch below for a description of what it actually does. Technical details of note (or controversy): - See the use of "zlc_active" and "did_zlc_setup" below, to delay adding any work for this new mechanism until we've looked at the first zone in zonelist. I figured the odds of the first zone having the memory we needed were high enough that we should just look there, first, then get fancy only if we need to keep looking. - Some odd hackery was needed to add items to struct zonelist, while not tripping up the custom zonelists built by the mm/mempolicy.c code for MPOL_BIND. My usual wordy comments below explain this. Search for "MPOL_BIND". - Some per-node data in the struct zonelist is now modified frequently, with no locking. Multiple CPU cores on a node could hit and mangle this data. The theory is that this is just performance hint data, and the memory allocator will work just fine despite any such mangling. The fields at risk are the struct 'zonelist_cache' fields 'fullzones' (a bitmask) and 'last_full_zap' (unsigned long jiffies). It should all be self correcting after at most a one second delay. - This still does a linear scan of the same lengths as before. All I've optimized is making the scan faster, not algorithmically shorter. It is now able to scan a compact array of 'unsigned short' in the case of many full nodes, so one cache line should cover quite a few nodes, rather than each node hitting another one or two new and distinct cache lines. - If both Andi and Nick don't find this too complicated, I will be (pleasantly) flabbergasted. - I removed the comment claiming we only use one cachline's worth of zonelist. We seem, at least in the fake numa case, to have put the lie to that claim. - I pay no attention to the various watermarks and such in this performance hint. A node could be marked full for one watermark, and then skipped over when searching for a page using a different watermark. I think that's actually quite ok, as it will tend to slightly increase the spreading of memory over other nodes, away from a memory stressed node. =============== Performance - some benchmark results and analysis: This benchmark runs a memory hog program that uses multiple threads to touch alot of memory as quickly as it can. Multiple runs were made, touching 12, 38, 64 or 90 GBytes out of the total 96 GBytes on the system, and using 1, 19, 37, or 55 threads (on a 56 CPU system.) System, user and real (elapsed) timings were recorded for each run, shown in units of seconds, in the table below. Two kernels were tested - 2.6.18-mm3 and the same kernel with this zonelist caching patch added. The table also shows the percentage improvement the zonelist caching sys time is over (lower than) the stock *-mm kernel. number 2.6.18-mm3 zonelist-cache delta (< 0 good) percent GBs N ------------ -------------- ---------------- systime mem threads sys user real sys user real sys user real better 12 1 153 24 177 151 24 176 -2 0 -1 1% 12 19 99 22 8 99 22 8 0 0 0 0% 12 37 111 25 6 112 25 6 1 0 0 -0% 12 55 115 25 5 110 23 5 -5 -2 0 4% 38 1 502 74 576 497 73 570 -5 -1 -6 0% 38 19 426 78 48 373 76 39 -53 -2 -9 12% 38 37 544 83 36 547 82 36 3 -1 0 -0% 38 55 501 77 23 511 80 24 10 3 1 -1% 64 1 917 125 1042 890 124 1014 -27 -1 -28 2% 64 19 1118 138 119 965 141 103 -153 3 -16 13% 64 37 1202 151 94 1136 150 81 -66 -1 -13 5% 64 55 1118 141 61 1072 140 58 -46 -1 -3 4% 90 1 1342 177 1519 1275 174 1450 -67 -3 -69 4% 90 19 2392 199 192 2116 189 176 -276 -10 -16 11% 90 37 3313 238 175 2972 225 145 -341 -13 -30 10% 90 55 1948 210 104 1843 213 100 -105 3 -4 5% Notes: 1) This test ran a memory hog program that started a specified number N of threads, and had each thread allocate and touch 1/N'th of the total memory to be used in the test run in a single loop, writing a constant word to memory, one store every 4096 bytes. Watching this test during some earlier trial runs, I would see each of these threads sit down on one CPU and stay there, for the remainder of the pass, a different CPU for each thread. 2) The 'real' column is not comparable to the 'sys' or 'user' columns. The 'real' column is seconds wall clock time elapsed, from beginning to end of that test pass. The 'sys' and 'user' columns are total CPU seconds spent on that test pass. For a 19 thread test run, for example, the sum of 'sys' and 'user' could be up to 19 times the number of 'real' elapsed wall clock seconds. 3) Tests were run on a fresh, single-user boot, to minimize the amount of memory already in use at the start of the test, and to minimize the amount of background activity that might interfere. 4) Tests were done on a 56 CPU, 28 Node system with 96 GBytes of RAM. 5) Notice that the 'real' time gets large for the single thread runs, even though the measured 'sys' and 'user' times are modest. I'm not sure what that means - probably something to do with it being slow for one thread to be accessing memory along ways away. Perhaps the fake numa system, running ostensibly the same workload, would not show this substantial degradation of 'real' time for one thread on many nodes -- lets hope not. 6) The high thread count passes (one thread per CPU - on 55 of 56 CPUs) ran quite efficiently, as one might expect. Each pair of threads needed to allocate and touch the memory on the node the two threads shared, a pleasantly parallizable workload. 7) The intermediate thread count passes, when asking for alot of memory forcing them to go to a few neighboring nodes, improved the most with this zonelist caching patch. Conclusions: * This zonelist cache patch probably makes little difference one way or the other for most workloads on real numa hardware, if those workloads avoid heavy off node allocations. * For memory intensive workloads requiring substantial off-node allocations on real numa hardware, this patch improves both kernel and elapsed timings up to ten per-cent. * For fake numa systems, I'm optimistic, but will have to leave that up to Rohit Seth to actually test (once I get him a 2.6.18 backport.) Signed-off-by: Paul Jackson Cc: Rohit Seth Cc: Christoph Lameter Cc: David Rientjes Cc: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 85 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 80 insertions(+), 5 deletions(-) (limited to 'include/linux/mmzone.h') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e06683e2bea3..09bf9d8d7b72 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -288,19 +288,94 @@ struct zone { */ #define DEF_PRIORITY 12 +/* Maximum number of zones on a zonelist */ +#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES) + +#ifdef CONFIG_NUMA +/* + * We cache key information from each zonelist for smaller cache + * footprint when scanning for free pages in get_page_from_freelist(). + * + * 1) The BITMAP fullzones tracks which zones in a zonelist have come + * up short of free memory since the last time (last_fullzone_zap) + * we zero'd fullzones. + * 2) The array z_to_n[] maps each zone in the zonelist to its node + * id, so that we can efficiently evaluate whether that node is + * set in the current tasks mems_allowed. + * + * Both fullzones and z_to_n[] are one-to-one with the zonelist, + * indexed by a zones offset in the zonelist zones[] array. + * + * The get_page_from_freelist() routine does two scans. During the + * first scan, we skip zones whose corresponding bit in 'fullzones' + * is set or whose corresponding node in current->mems_allowed (which + * comes from cpusets) is not set. During the second scan, we bypass + * this zonelist_cache, to ensure we look methodically at each zone. + * + * Once per second, we zero out (zap) fullzones, forcing us to + * reconsider nodes that might have regained more free memory. + * The field last_full_zap is the time we last zapped fullzones. + * + * This mechanism reduces the amount of time we waste repeatedly + * reexaming zones for free memory when they just came up low on + * memory momentarilly ago. + * + * The zonelist_cache struct members logically belong in struct + * zonelist. However, the mempolicy zonelists constructed for + * MPOL_BIND are intentionally variable length (and usually much + * shorter). A general purpose mechanism for handling structs with + * multiple variable length members is more mechanism than we want + * here. We resort to some special case hackery instead. + * + * The MPOL_BIND zonelists don't need this zonelist_cache (in good + * part because they are shorter), so we put the fixed length stuff + * at the front of the zonelist struct, ending in a variable length + * zones[], as is needed by MPOL_BIND. + * + * Then we put the optional zonelist cache on the end of the zonelist + * struct. This optional stuff is found by a 'zlcache_ptr' pointer in + * the fixed length portion at the front of the struct. This pointer + * both enables us to find the zonelist cache, and in the case of + * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL) + * to know that the zonelist cache is not there. + * + * The end result is that struct zonelists come in two flavors: + * 1) The full, fixed length version, shown below, and + * 2) The custom zonelists for MPOL_BIND. + * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache. + * + * Even though there may be multiple CPU cores on a node modifying + * fullzones or last_full_zap in the same zonelist_cache at the same + * time, we don't lock it. This is just hint data - if it is wrong now + * and then, the allocator will still function, perhaps a bit slower. + */ + + +struct zonelist_cache { + DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ + unsigned short z_to_n[MAX_ZONES_PER_ZONELIST]; /* zone->nid */ + unsigned long last_full_zap; /* when last zap'd (jiffies) */ +}; +#else +struct zonelist_cache; +#endif + /* * One allocation request operates on a zonelist. A zonelist * is a list of zones, the first one is the 'goal' of the * allocation, the other zones are fallback zones, in decreasing * priority. * - * Right now a zonelist takes up less than a cacheline. We never - * modify it apart from boot-up, and only a few indices are used, - * so despite the zonelist table being relatively big, the cache - * footprint of this construct is very small. + * If zlcache_ptr is not NULL, then it is just the address of zlcache, + * as explained above. If zlcache_ptr is NULL, there is no zlcache. */ + struct zonelist { - struct zone *zones[MAX_NUMNODES * MAX_NR_ZONES + 1]; // NULL delimited + struct zonelist_cache *zlcache_ptr; // NULL or &zlcache + struct zone *zones[MAX_ZONES_PER_ZONELIST + 1]; // NULL delimited +#ifdef CONFIG_NUMA + struct zonelist_cache zlcache; // optional ... +#endif }; #ifdef CONFIG_ARCH_POPULATES_NODE_MAP -- cgit v1.2.3 From 7253f4ef04b1cd138baf2b29a95473743ac0a307 Mon Sep 17 00:00:00 2001 From: Paul Jackson Date: Wed, 6 Dec 2006 20:31:49 -0800 Subject: [PATCH] memory page_alloc zonelist caching reorder structure Rearrange the struct members in the 'struct zonelist_cache' structure, so as to put the readonly (once initialized) z_to_n[] array first, where it will come right after the zones[] array in struct zonelist. This pretty much eliminates the chance that the two frequently written elements of 'struct zonelist_cache', the fullzones bitmap and last_full_zap times, will end up on the same cache line as the performance sensitive, frequently read, never (after init) written zones[] array. Keeping frequently written data off frequently read cache lines is good for performance. Thanks to Rohit Seth for the suggestion. Signed-off-by: Paul Jackson Cc: Rohit Seth Cc: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mmzone.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/mmzone.h') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 09bf9d8d7b72..da6002dec205 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -352,8 +352,8 @@ struct zone { struct zonelist_cache { - DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ unsigned short z_to_n[MAX_ZONES_PER_ZONELIST]; /* zone->nid */ + DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ unsigned long last_full_zap; /* when last zap'd (jiffies) */ }; #else -- cgit v1.2.3 From 15ad7cdcfd76450d4beebc789ec646664238184d Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Wed, 6 Dec 2006 20:40:36 -0800 Subject: [PATCH] struct seq_operations and struct file_operations constification - move some file_operations structs into the .rodata section - move static strings from policy_types[] array into the .rodata section - fix generic seq_operations usages, so that those structs may be defined as "const" as well [akpm@osdl.org: couple of fixes] Signed-off-by: Helge Deller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/seq_file.c | 4 ++-- include/linux/cpuset.h | 2 +- include/linux/mmzone.h | 2 +- include/linux/relay.h | 2 +- include/linux/sched.h | 2 +- include/linux/seq_file.h | 4 ++-- kernel/configs.c | 2 +- kernel/cpuset.c | 4 ++-- kernel/dma.c | 2 +- kernel/futex.c | 2 +- kernel/kallsyms.c | 4 ++-- kernel/lockdep_proc.c | 6 +++--- kernel/module.c | 2 +- kernel/power/user.c | 2 +- kernel/profile.c | 2 +- kernel/relay.c | 2 +- kernel/resource.c | 6 +++--- kernel/sched.c | 2 +- kernel/sysctl.c | 2 +- mm/mempolicy.c | 4 ++-- mm/page_alloc.c | 2 +- mm/shmem.c | 4 ++-- mm/slab.c | 4 ++-- mm/swapfile.c | 4 ++-- mm/vmstat.c | 8 ++++---- 25 files changed, 40 insertions(+), 40 deletions(-) (limited to 'include/linux/mmzone.h') diff --git a/fs/seq_file.c b/fs/seq_file.c index 555b9ac04c25..10690aa401c7 100644 --- a/fs/seq_file.c +++ b/fs/seq_file.c @@ -26,7 +26,7 @@ * ERR_PTR(error). In the end of sequence they return %NULL. ->show() * returns 0 in case of success and negative number in case of error. */ -int seq_open(struct file *file, struct seq_operations *op) +int seq_open(struct file *file, const struct seq_operations *op) { struct seq_file *p = file->private_data; @@ -408,7 +408,7 @@ EXPORT_SYMBOL(single_open); int single_release(struct inode *inode, struct file *file) { - struct seq_operations *op = ((struct seq_file *)file->private_data)->op; + const struct seq_operations *op = ((struct seq_file *)file->private_data)->op; int res = seq_release(inode, file); kfree(op); return res; diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index 748d2c996631..8821e1f75b44 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -46,7 +46,7 @@ extern int cpuset_excl_nodes_overlap(const struct task_struct *p); extern int cpuset_memory_pressure_enabled; extern void __cpuset_memory_pressure_bump(void); -extern struct file_operations proc_cpuset_operations; +extern const struct file_operations proc_cpuset_operations; extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer); extern void cpuset_lock(void); diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index da6002dec205..e339a7345f25 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -278,7 +278,7 @@ struct zone { /* * rarely used fields: */ - char *name; + const char *name; } ____cacheline_internodealigned_in_smp; /* diff --git a/include/linux/relay.h b/include/linux/relay.h index 0e3d91b76996..c6a48bfc8b14 100644 --- a/include/linux/relay.h +++ b/include/linux/relay.h @@ -274,7 +274,7 @@ static inline void subbuf_start_reserve(struct rchan_buf *buf, /* * exported relay file operations, kernel/relay.c */ -extern struct file_operations relay_file_operations; +extern const struct file_operations relay_file_operations; #endif /* _LINUX_RELAY_H */ diff --git a/include/linux/sched.h b/include/linux/sched.h index 3a767242e72f..dede82c63445 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -573,7 +573,7 @@ struct sched_info { #endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */ #ifdef CONFIG_SCHEDSTATS -extern struct file_operations proc_schedstat_operations; +extern const struct file_operations proc_schedstat_operations; #endif /* CONFIG_SCHEDSTATS */ #ifdef CONFIG_TASK_DELAY_ACCT diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index b95f6eb7254c..3e3cccbb1cac 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -20,7 +20,7 @@ struct seq_file { loff_t index; loff_t version; struct mutex lock; - struct seq_operations *op; + const struct seq_operations *op; void *private; }; @@ -31,7 +31,7 @@ struct seq_operations { int (*show) (struct seq_file *m, void *v); }; -int seq_open(struct file *, struct seq_operations *); +int seq_open(struct file *, const struct seq_operations *); ssize_t seq_read(struct file *, char __user *, size_t, loff_t *); loff_t seq_lseek(struct file *, loff_t, int); int seq_release(struct inode *, struct file *); diff --git a/kernel/configs.c b/kernel/configs.c index f9e31974f4ad..8fa1fb28f8a7 100644 --- a/kernel/configs.c +++ b/kernel/configs.c @@ -75,7 +75,7 @@ ikconfig_read_current(struct file *file, char __user *buf, return count; } -static struct file_operations ikconfig_file_ops = { +static const struct file_operations ikconfig_file_ops = { .owner = THIS_MODULE, .read = ikconfig_read_current, }; diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 9b62b4c03ad0..4ef1d29297ca 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1531,7 +1531,7 @@ static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry, return simple_rename(old_dir, old_dentry, new_dir, new_dentry); } -static struct file_operations cpuset_file_operations = { +static const struct file_operations cpuset_file_operations = { .read = cpuset_file_read, .write = cpuset_file_write, .llseek = generic_file_llseek, @@ -2605,7 +2605,7 @@ static int cpuset_open(struct inode *inode, struct file *file) return single_open(file, proc_cpuset_show, pid); } -struct file_operations proc_cpuset_operations = { +const struct file_operations proc_cpuset_operations = { .open = cpuset_open, .read = seq_read, .llseek = seq_lseek, diff --git a/kernel/dma.c b/kernel/dma.c index 2020644c938a..937b13ca33ba 100644 --- a/kernel/dma.c +++ b/kernel/dma.c @@ -140,7 +140,7 @@ static int proc_dma_open(struct inode *inode, struct file *file) return single_open(file, proc_dma_show, NULL); } -static struct file_operations proc_dma_operations = { +static const struct file_operations proc_dma_operations = { .open = proc_dma_open, .read = seq_read, .llseek = seq_lseek, diff --git a/kernel/futex.c b/kernel/futex.c index a8302a1620ea..95989a3b4168 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1492,7 +1492,7 @@ static unsigned int futex_poll(struct file *filp, return ret; } -static struct file_operations futex_fops = { +static const struct file_operations futex_fops = { .release = futex_close, .poll = futex_poll, }; diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 54befe36ee0b..ab63cfc42992 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -398,7 +398,7 @@ static int s_show(struct seq_file *m, void *p) return 0; } -static struct seq_operations kallsyms_op = { +static const struct seq_operations kallsyms_op = { .start = s_start, .next = s_next, .stop = s_stop, @@ -433,7 +433,7 @@ static int kallsyms_release(struct inode *inode, struct file *file) return seq_release(inode, file); } -static struct file_operations kallsyms_operations = { +static const struct file_operations kallsyms_operations = { .open = kallsyms_open, .read = seq_read, .llseek = seq_lseek, diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index f6e72eaab3fa..b554b40a4aa6 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -113,7 +113,7 @@ static int l_show(struct seq_file *m, void *v) return 0; } -static struct seq_operations lockdep_ops = { +static const struct seq_operations lockdep_ops = { .start = l_start, .next = l_next, .stop = l_stop, @@ -135,7 +135,7 @@ static int lockdep_open(struct inode *inode, struct file *file) return res; } -static struct file_operations proc_lockdep_operations = { +static const struct file_operations proc_lockdep_operations = { .open = lockdep_open, .read = seq_read, .llseek = seq_lseek, @@ -319,7 +319,7 @@ static int lockdep_stats_open(struct inode *inode, struct file *file) return single_open(file, lockdep_stats_show, NULL); } -static struct file_operations proc_lockdep_stats_operations = { +static const struct file_operations proc_lockdep_stats_operations = { .open = lockdep_stats_open, .read = seq_read, .llseek = seq_lseek, diff --git a/kernel/module.c b/kernel/module.c index e2d09d604ca0..d9eae45d0145 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2209,7 +2209,7 @@ static int m_show(struct seq_file *m, void *p) Where refcount is a number or -, and deps is a comma-separated list of depends or -. */ -struct seq_operations modules_op = { +const struct seq_operations modules_op = { .start = m_start, .next = m_next, .stop = m_stop, diff --git a/kernel/power/user.c b/kernel/power/user.c index 069732e5695c..89443b85163b 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -383,7 +383,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp, return error; } -static struct file_operations snapshot_fops = { +static const struct file_operations snapshot_fops = { .open = snapshot_open, .release = snapshot_release, .read = snapshot_read, diff --git a/kernel/profile.c b/kernel/profile.c index 0961d93e1d91..fb5e03d57e9d 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -501,7 +501,7 @@ static ssize_t write_profile(struct file *file, const char __user *buf, return count; } -static struct file_operations proc_profile_operations = { +static const struct file_operations proc_profile_operations = { .read = read_profile, .write = write_profile, }; diff --git a/kernel/relay.c b/kernel/relay.c index 2b92e8ece85b..75a3a9a7efc2 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -1013,7 +1013,7 @@ static ssize_t relay_file_sendfile(struct file *filp, actor, &desc); } -struct file_operations relay_file_operations = { +const struct file_operations relay_file_operations = { .open = relay_file_open, .poll = relay_file_poll, .mmap = relay_file_mmap, diff --git a/kernel/resource.c b/kernel/resource.c index 6de60c12143e..7b9a497419d9 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -88,7 +88,7 @@ static int r_show(struct seq_file *m, void *v) return 0; } -static struct seq_operations resource_op = { +static const struct seq_operations resource_op = { .start = r_start, .next = r_next, .stop = r_stop, @@ -115,14 +115,14 @@ static int iomem_open(struct inode *inode, struct file *file) return res; } -static struct file_operations proc_ioports_operations = { +static const struct file_operations proc_ioports_operations = { .open = ioports_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, }; -static struct file_operations proc_iomem_operations = { +static const struct file_operations proc_iomem_operations = { .open = iomem_open, .read = seq_read, .llseek = seq_lseek, diff --git a/kernel/sched.c b/kernel/sched.c index b43cef02ce5b..f385eff4682d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -505,7 +505,7 @@ static int schedstat_open(struct inode *inode, struct file *file) return res; } -struct file_operations proc_schedstat_operations = { +const struct file_operations proc_schedstat_operations = { .open = schedstat_open, .read = seq_read, .llseek = seq_lseek, diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 6d7147cf66bb..758dbbf972a5 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -170,7 +170,7 @@ static ssize_t proc_readsys(struct file *, char __user *, size_t, loff_t *); static ssize_t proc_writesys(struct file *, const char __user *, size_t, loff_t *); static int proc_opensys(struct inode *, struct file *); -struct file_operations proc_sys_file_operations = { +const struct file_operations proc_sys_file_operations = { .open = proc_opensys, .read = proc_readsys, .write = proc_writesys, diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ad864f8708b0..b917d6fdc1bb 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1707,8 +1707,8 @@ void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new) * Display pages allocated per node and memory policy via /proc. */ -static const char *policy_types[] = { "default", "prefer", "bind", - "interleave" }; +static const char * const policy_types[] = + { "default", "prefer", "bind", "interleave" }; /* * Convert a mempolicy into a string. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 27ec7a1b8022..cace22b3ac25 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -83,7 +83,7 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { EXPORT_SYMBOL(totalram_pages); -static char *zone_names[MAX_NR_ZONES] = { +static char * const zone_names[MAX_NR_ZONES] = { "DMA", #ifdef CONFIG_ZONE_DMA32 "DMA32", diff --git a/mm/shmem.c b/mm/shmem.c index 007653680a75..c820b4f77b8d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -177,7 +177,7 @@ static inline void shmem_unacct_blocks(unsigned long flags, long pages) static struct super_operations shmem_ops; static const struct address_space_operations shmem_aops; -static struct file_operations shmem_file_operations; +static const struct file_operations shmem_file_operations; static struct inode_operations shmem_inode_operations; static struct inode_operations shmem_dir_inode_operations; static struct inode_operations shmem_special_inode_operations; @@ -2319,7 +2319,7 @@ static const struct address_space_operations shmem_aops = { .migratepage = migrate_page, }; -static struct file_operations shmem_file_operations = { +static const struct file_operations shmem_file_operations = { .mmap = shmem_mmap, #ifdef CONFIG_TMPFS .llseek = generic_file_llseek, diff --git a/mm/slab.c b/mm/slab.c index 86f5d6e995bb..068cb4503c15 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4142,7 +4142,7 @@ static int s_show(struct seq_file *m, void *p) * + further values on SMP and with statistics enabled */ -struct seq_operations slabinfo_op = { +const struct seq_operations slabinfo_op = { .start = s_start, .next = s_next, .stop = s_stop, @@ -4340,7 +4340,7 @@ static int leaks_show(struct seq_file *m, void *p) return 0; } -struct seq_operations slabstats_op = { +const struct seq_operations slabstats_op = { .start = leaks_start, .next = s_next, .stop = s_stop, diff --git a/mm/swapfile.c b/mm/swapfile.c index 55242363de64..c5431072f422 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1368,7 +1368,7 @@ static int swap_show(struct seq_file *swap, void *v) return 0; } -static struct seq_operations swaps_op = { +static const struct seq_operations swaps_op = { .start = swap_start, .next = swap_next, .stop = swap_stop, @@ -1380,7 +1380,7 @@ static int swaps_open(struct inode *inode, struct file *file) return seq_open(file, &swaps_op); } -static struct file_operations proc_swaps_operations = { +static const struct file_operations proc_swaps_operations = { .open = swaps_open, .read = seq_read, .llseek = seq_lseek, diff --git a/mm/vmstat.c b/mm/vmstat.c index ef4176843d9e..dc005a0c96ae 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -430,7 +430,7 @@ static int frag_show(struct seq_file *m, void *arg) return 0; } -struct seq_operations fragmentation_op = { +const struct seq_operations fragmentation_op = { .start = frag_start, .next = frag_next, .stop = frag_stop, @@ -452,7 +452,7 @@ struct seq_operations fragmentation_op = { #define TEXTS_FOR_ZONES(xx) xx "_dma", TEXT_FOR_DMA32(xx) xx "_normal", \ TEXT_FOR_HIGHMEM(xx) -static char *vmstat_text[] = { +static const char * const vmstat_text[] = { /* Zoned VM counters */ "nr_anon_pages", "nr_mapped", @@ -597,7 +597,7 @@ static int zoneinfo_show(struct seq_file *m, void *arg) return 0; } -struct seq_operations zoneinfo_op = { +const struct seq_operations zoneinfo_op = { .start = frag_start, /* iterate over all zones. The same as in * fragmentation. */ .next = frag_next, @@ -660,7 +660,7 @@ static void vmstat_stop(struct seq_file *m, void *arg) m->private = NULL; } -struct seq_operations vmstat_op = { +const struct seq_operations vmstat_op = { .start = vmstat_start, .next = vmstat_next, .stop = vmstat_stop, -- cgit v1.2.3