Viewing: cl_page.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2011, 2017, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
*
* Client Lustre Page.
*
* Author: Nikita Danilov <nikita.danilov@sun.com>
* Author: Jinshan Xiong <jinshan.xiong@intel.com>
*/
#define DEBUG_SUBSYSTEM S_CLASS
#include <linux/list.h>
#include <lustre_compat/linux/uio.h>
#include <obd_class.h>
#include <obd_support.h>
#include <cl_object.h>
#include "cl_internal.h"
static void __cl_page_delete(const struct lu_env *env, struct cl_page *pg);
static DEFINE_MUTEX(cl_page_kmem_mutex);
#ifdef LIBCFS_DEBUG
# define PASSERT(env, page, expr) \
do { \
if (unlikely(!(expr))) { \
CL_PAGE_DEBUG(D_ERROR, (env), (page), #expr "\n"); \
LASSERT(0); \
} \
} while (0)
#else /* !LIBCFS_DEBUG */
#define PASSERT(env, page, exp) \
((void)sizeof(env), (void)sizeof(page), (void)sizeof !!(exp))
#endif /* !LIBCFS_DEBUG */
#ifdef CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK
# define PINVRNT(env, page, expr) \
do { \
if (unlikely(!(expr))) { \
CL_PAGE_DEBUG(D_ERROR, (env), (page), #expr "\n"); \
LINVRNT(0); \
} \
} while (0)
#else /* !CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK */
# define PINVRNT(env, page, exp) \
((void)sizeof(env), (void)sizeof(page), (void)sizeof !!(exp))
#endif /* !CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK */
/* Disable page statistic by default due to huge performance penalty. */
static void cs_page_inc(const struct cl_object *obj,
enum cache_stats_item item)
{
#ifdef CONFIG_DEBUG_PAGESTATE_TRACKING
atomic_inc(&cl_object_site(obj)->cs_pages.cs_stats[item]);
#endif
}
static void cs_page_dec(const struct cl_object *obj,
enum cache_stats_item item)
{
#ifdef CONFIG_DEBUG_PAGESTATE_TRACKING
atomic_dec(&cl_object_site(obj)->cs_pages.cs_stats[item]);
#endif
}
static void cs_pagestate_inc(const struct cl_object *obj,
enum cl_page_state state)
{
#ifdef CONFIG_DEBUG_PAGESTATE_TRACKING
atomic_inc(&cl_object_site(obj)->cs_pages_state[state]);
#endif
}
static void cs_pagestate_dec(const struct cl_object *obj,
enum cl_page_state state)
{
#ifdef CONFIG_DEBUG_PAGESTATE_TRACKING
atomic_dec(&cl_object_site(obj)->cs_pages_state[state]);
#endif
}
/*
* Internal version of cl_page_get().
*
* This function can be used to obtain initial reference to previously
* unreferenced cached object. It can be called only if concurrent page
* reclamation is somehow prevented, e.g., by keeping a lock on a VM page,
* associated with \a page.
*
* Use with care! Not exported.
*/
static void cl_page_get_trust(struct cl_page *page)
{
LASSERT(refcount_read(&page->cp_ref) > 0);
refcount_inc(&page->cp_ref);
}
static struct cl_page_slice *
cl_page_slice_get(const struct cl_page *cl_page, int index)
{
if (index < 0 || index >= cl_page->cp_layer_count)
return NULL;
/* To get the cp_layer_offset values fit under 256 bytes, we
* use the offset beyond the end of struct cl_page.
*/
return (struct cl_page_slice *)((char *)cl_page + sizeof(*cl_page) +
cl_page->cp_layer_offset[index]);
}
#define cl_page_slice_for_each(cl_page, slice, i) \
for (i = 0, slice = cl_page_slice_get(cl_page, 0); \
i < (cl_page)->cp_layer_count; \
slice = cl_page_slice_get(cl_page, ++i))
#define cl_page_slice_for_each_reverse(cl_page, slice, i) \
for (i = (cl_page)->cp_layer_count - 1, \
slice = cl_page_slice_get(cl_page, i); i >= 0; \
slice = cl_page_slice_get(cl_page, --i))
/* does the work required to access the pages in the iov, be they userspace
* or kernel
*
* returns number of bytes
*/
static ssize_t ll_get_iov_memory(int rw, struct iov_iter *iter,
struct cl_dio_pages *cdp,
size_t maxsize)
{
ssize_t bytes;
size_t start;
bytes = iov_iter_get_pages_alloc2(iter, &cdp->cdp_pages, maxsize,
&start);
if (bytes > 0) {
cdp->cdp_page_count = DIV_ROUND_UP(bytes + start, PAGE_SIZE);
if (user_backed_iter(iter))
iov_iter_revert(iter, bytes);
}
return bytes;
}
ssize_t cl_dio_pages_init(const struct lu_env *env, struct cl_object *obj,
struct cl_dio_pages *cdp, struct iov_iter *iter,
int rw, size_t bytes, loff_t offset, bool unaligned)
{
struct cl_object *head = obj;
pgoff_t index = offset >> PAGE_SHIFT;
ssize_t result = 0;
ENTRY;
cdp->cdp_file_offset = offset;
cdp->cdp_from = offset & ~PAGE_MASK;
cdp->cdp_to = ((offset + bytes - 1) & ~PAGE_MASK);
/* these set cdp->page_count, which is used in coo_dio_pages_init */
if (!unaligned) {
result = ll_get_iov_memory(rw, iter, cdp, bytes);
/* ll_get_iov_memory returns bytes in the IO or error*/
bytes = result;
} else {
/* explictly handle the ubuf() case for el9.4 */
size_t len = iter_is_ubuf(iter) ? iov_iter_count(iter)
: iter_iov(iter)->iov_len;
/* same calculation used in ll_get_user_pages */
bytes = min_t(size_t, bytes, len);
result = ll_allocate_dio_buffer(cdp, bytes);
/* allocate_dio_buffer returns number of pages or
* error, so do not set bytes = result
*/
if (result > 0)
result = 0;
}
if (result < 0)
GOTO(out, result);
LASSERT(cdp->cdp_page_count);
/* this is special temporary allocation which lets us track the
* cl_pages and convert them to a list
*
* this is used in 'pushing down' the conversion to a page queue
*/
OBD_ALLOC_PTR_ARRAY_LARGE(cdp->cdp_cl_pages, cdp->cdp_page_count);
if (!cdp->cdp_cl_pages)
GOTO(out, result = -ENOMEM);
cl_object_for_each(obj, head) {
if (obj->co_ops->coo_dio_pages_init != NULL) {
result = obj->co_ops->coo_dio_pages_init(env, obj,
cdp, index);
if (result != 0) {
LASSERT(result < 0);
GOTO(out, result);
}
}
}
out:
if (result >= 0)
result = bytes;
RETURN(result);
}
EXPORT_SYMBOL(cl_dio_pages_init);
static void __cl_page_free(struct cl_page *cl_page, unsigned short bufsize)
{
if (cl_page->cp_in_kmem_array) {
int index = cl_page->cp_kmem_index;
LASSERT(index < ARRAY_SIZE(cl_page_kmem_array));
LASSERT(cl_page_kmem_size_array[index] == bufsize);
OBD_SLAB_FREE(cl_page, cl_page_kmem_array[index], bufsize);
} else {
OBD_FREE(cl_page, bufsize);
}
}
static void cl_page_free(const struct lu_env *env, struct cl_page *cp,
struct folio_batch *fbatch)
{
struct cl_object *obj = cp->cp_obj;
unsigned short bufsize;
struct page *vmpage;
ENTRY;
PASSERT(env, cp, list_empty(&cp->cp_batch));
if (cp->cp_type == CPT_CACHEABLE) {
PASSERT(env, cp, cp->cp_owner == NULL);
PASSERT(env, cp, cp->cp_state == CPS_FREEING);
/* vmpage->private was already cleared when page was
* moved into CPS_FREEING state.
*/
vmpage = cp->cp_vmpage;
LASSERT(vmpage != NULL);
LASSERT((struct cl_page *)vmpage->private != cp);
if (fbatch != NULL) {
if (!folio_batch_add_page(fbatch, vmpage))
folio_batch_release(fbatch);
} else {
put_page(vmpage);
}
}
cp->cp_layer_count = 0;
cs_page_dec(obj, CS_total);
if (cp->cp_type != CPT_TRANSIENT)
cs_pagestate_dec(obj, cp->cp_state);
if (cp->cp_type != CPT_TRANSIENT)
cl_object_put(env, obj);
if (cp->cp_in_kmem_array)
bufsize = cl_page_kmem_size_array[cp->cp_kmem_index];
else
bufsize = cp->cp_kmem_size;
if (unlikely(bufsize != cl_object_header(obj)->coh_page_bufsize))
CWARN("%s:"DFID" page bufsize %d, object bufsize now %d\n",
obj->co_lu.lo_dev->ld_obd->obd_name,
PFID(&cl_object_header(obj)->coh_lu.loh_fid),
bufsize, cl_object_header(obj)->coh_page_bufsize);
__cl_page_free(cp, bufsize);
EXIT;
}
static struct cl_page *__cl_page_alloc(struct cl_object *o)
{
int i = 0;
struct cl_page *cl_page = NULL;
unsigned short bufsize = cl_object_header(o)->coh_page_bufsize;
if (CFS_FAIL_CHECK(OBD_FAIL_LLITE_PAGE_ALLOC))
return NULL;
check:
/* the number of entries in cl_page_kmem_array is expected to
* only be 2-3 entries, so the lookup overhead should be low.
*/
for ( ; i < ARRAY_SIZE(cl_page_kmem_array); i++) {
if (smp_load_acquire(&cl_page_kmem_size_array[i]) == bufsize) {
OBD_SLAB_ALLOC_GFP(cl_page, cl_page_kmem_array[i],
bufsize, GFP_NOFS);
if (cl_page) {
cl_page->cp_in_kmem_array = 1;
cl_page->cp_kmem_index = i;
}
return cl_page;
}
if (cl_page_kmem_size_array[i] == 0)
break;
}
if (i < ARRAY_SIZE(cl_page_kmem_array)) {
char cache_name[32];
mutex_lock(&cl_page_kmem_mutex);
if (cl_page_kmem_size_array[i]) {
mutex_unlock(&cl_page_kmem_mutex);
goto check;
}
snprintf(cache_name, sizeof(cache_name),
"cl_page_kmem-%u", bufsize);
cl_page_kmem_array[i] =
kmem_cache_create(cache_name, bufsize,
0, 0, NULL);
if (cl_page_kmem_array[i] == NULL) {
mutex_unlock(&cl_page_kmem_mutex);
return NULL;
}
smp_store_release(&cl_page_kmem_size_array[i], bufsize);
mutex_unlock(&cl_page_kmem_mutex);
goto check;
} else {
OBD_ALLOC_GFP(cl_page, bufsize, GFP_NOFS);
if (cl_page) {
cl_page->cp_in_kmem_array = 0;
cl_page->cp_kmem_size = bufsize;
}
}
return cl_page;
}
struct cl_page *cl_page_alloc(const struct lu_env *env, struct cl_object *o,
pgoff_t ind, struct page *vmpage,
enum cl_page_type type)
{
struct cl_page *cl_page;
struct cl_object *head;
ENTRY;
cl_page = __cl_page_alloc(o);
if (cl_page != NULL) {
int result = 0;
/* Please fix cl_page:cp_state/type declaration if
* these assertions fail in the future.
*/
BUILD_BUG_ON((1 << CP_STATE_BITS) < CPS_NR); /* cp_state */
BUILD_BUG_ON((1 << CP_TYPE_BITS) < CPT_NR); /* cp_type */
refcount_set(&cl_page->cp_ref, 1);
cl_page->cp_obj = o;
if (type != CPT_TRANSIENT)
cl_object_get(o);
cl_page->cp_vmpage = vmpage;
if (cl_page->cp_type != CPT_TRANSIENT)
cl_page->cp_state = CPS_CACHED;
cl_page->cp_type = type;
if (type == CPT_TRANSIENT)
/* correct inode to be added in ll_direct_rw_pages */
cl_page->cp_inode = NULL;
else
cl_page->cp_inode = page2inode(vmpage);
INIT_LIST_HEAD(&cl_page->cp_batch);
head = o;
cl_page->cp_page_index = ind;
cl_object_for_each(o, head) {
if (o->co_ops->coo_page_init != NULL) {
result = o->co_ops->coo_page_init(env, o,
cl_page, ind);
if (result != 0) {
__cl_page_delete(env, cl_page);
cl_page_free(env, cl_page, NULL);
cl_page = ERR_PTR(result);
break;
}
}
}
if (result == 0) {
cs_page_inc(o, CS_total);
cs_page_inc(o, CS_create);
cs_pagestate_dec(o, CPS_CACHED);
}
} else {
cl_page = ERR_PTR(-ENOMEM);
}
RETURN(cl_page);
}
/**
* cl_page_find() - Returns a cl_page with index @idx at the object @o, and
* associated with the VM page @vmpage.
* @env: current lustre environment
* @o: layer which is finding the page
* @idx: offset
* @vmpage: pointer to kernel struct page
* @type: IO type (READ/WRITE)
*
* This is the main entry point into the cl_page caching interface. First, a
* cache (implemented as a per-object radix tree) is consulted. If page is
* found there, it is returned immediately. Otherwise new page is allocated
* and returned. In any case, additional reference to page is acquired.
*
* see cl_object_find(), cl_lock_find()
*
* Returns struct cl_page derived from @vmpage on success or NULL on failure
*/
struct cl_page *cl_page_find(const struct lu_env *env,
struct cl_object *o,
pgoff_t idx, struct page *vmpage,
enum cl_page_type type)
{
struct cl_page *page = NULL;
struct cl_object_header *hdr;
LASSERT(type == CPT_CACHEABLE || type == CPT_TRANSIENT);
might_sleep();
ENTRY;
hdr = cl_object_header(o);
cs_page_inc(o, CS_lookup);
CDEBUG(D_PAGE, "%lu@"DFID" %p %lx %d\n",
idx, PFID(&hdr->coh_lu.loh_fid), vmpage, vmpage->private, type);
/* fast path. */
if (type == CPT_CACHEABLE) {
/* vmpage lock used to protect the child/parent relationship */
LASSERT(PageLocked(vmpage));
/*
* cl_vmpage_page() can be called here without any locks as
*
* - "vmpage" is locked (which prevents ->private from
* concurrent updates), and
*
* - "o" cannot be destroyed while current thread holds a
* reference on it.
*/
page = cl_vmpage_page(vmpage, o);
if (page != NULL) {
cs_page_inc(o, CS_hit);
RETURN(page);
}
}
/* allocate and initialize cl_page */
page = cl_page_alloc(env, o, idx, vmpage, type);
RETURN(page);
}
EXPORT_SYMBOL(cl_page_find);
static inline int cl_page_invariant(const struct cl_page *pg)
{
return cl_page_in_use_noref(pg);
}
static void __cl_page_state_set(const struct lu_env *env,
struct cl_page *cl_page,
enum cl_page_state state)
{
enum cl_page_state old;
/* Matrix of allowed state transitions [old][new] for sanity checking */
static const int allowed_transitions[CPS_NR][CPS_NR] = {
[CPS_CACHED] = {
[CPS_CACHED] = 0,
[CPS_OWNED] = 1, /* io finds existing cached page */
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 1, /* write-out from the cache */
[CPS_FREEING] = 1, /* eviction on the memory pressure */
},
[CPS_OWNED] = {
[CPS_CACHED] = 1, /* release to the cache */
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 1, /* start read immediately */
[CPS_PAGEOUT] = 1, /* start write immediately */
[CPS_FREEING] = 1, /* lock invalidation or truncate */
},
[CPS_PAGEIN] = {
[CPS_CACHED] = 1, /* io completion */
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 0,
[CPS_FREEING] = 0,
},
[CPS_PAGEOUT] = {
[CPS_CACHED] = 1, /* io completion */
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 0,
[CPS_FREEING] = 0,
},
[CPS_FREEING] = {
[CPS_CACHED] = 0,
[CPS_OWNED] = 0,
[CPS_PAGEIN] = 0,
[CPS_PAGEOUT] = 0,
[CPS_FREEING] = 0,
}
};
ENTRY;
old = cl_page->cp_state;
PASSERT(env, cl_page, allowed_transitions[old][state]);
CL_PAGE_HEADER(D_TRACE, env, cl_page, "%d -> %d\n", old, state);
PASSERT(env, cl_page, cl_page->cp_state == old);
PASSERT(env, cl_page, equi(state == CPS_OWNED,
cl_page->cp_owner != NULL));
cs_pagestate_dec(cl_page->cp_obj, cl_page->cp_state);
cs_pagestate_inc(cl_page->cp_obj, state);
cl_page->cp_state = state;
EXIT;
}
static void cl_page_state_set(const struct lu_env *env,
struct cl_page *page, enum cl_page_state state)
{
LASSERT(page->cp_type != CPT_TRANSIENT);
__cl_page_state_set(env, page, state);
}
/**
* cl_page_get() - Acquires an additional reference to a page.
* @page: pointer to lustre page which reference is being added
*
* This can be called only by caller already possessing a reference to @page.
* see cl_object_get(), cl_lock_get().
*/
void cl_page_get(struct cl_page *page)
{
ENTRY;
cl_page_get_trust(page);
EXIT;
}
EXPORT_SYMBOL(cl_page_get);
/**
* cl_batch_put() - Releases a reference to a page
* @env: current lustre environment
* @page: cl_page instance to release referance
* @fbatch: pointer to folio_batch
*
* Releases a reference to a page, use the @fbatch to release the pages
* in batch if provided. Users need to do a final folio_batch_release() to
* release any trailing pages. If NULL call put_page() to release @page
* immediately
*/
void cl_batch_put(const struct lu_env *env, struct cl_page *page,
struct folio_batch *fbatch)
{
ENTRY;
CL_PAGE_HEADER(D_TRACE, env, page, "%d\n",
refcount_read(&page->cp_ref));
if (refcount_dec_and_test(&page->cp_ref)) {
if (page->cp_type != CPT_TRANSIENT) {
LASSERT(page->cp_state == CPS_FREEING);
PASSERT(env, page, page->cp_owner == NULL);
}
PASSERT(env, page, list_empty(&page->cp_batch));
/* Page is no longer reachable by other threads. Tear it down */
cl_page_free(env, page, fbatch);
}
EXIT;
}
EXPORT_SYMBOL(cl_batch_put);
/**
* cl_page_put() - Releases a reference to a page, wrapper to cl_batch_put
* @env: current lustre environment
* @page: cl_page instance to release referance
*
* When last reference is released, page is returned to the cache, unless it
* is in cl_page_state::CPS_FREEING state, in which case it is immediately
* destroyed. Last argument passed to cl_batch_put() if NULL means to call
* put_page() to release @page immediately
*
* see cl_object_put(), cl_lock_put().
*/
void cl_page_put(const struct lu_env *env, struct cl_page *page)
{
cl_batch_put(env, page, NULL);
}
EXPORT_SYMBOL(cl_page_put);
/**
* cl_vmpage_page() - Returns a cl_page associated with a VM page, for the
* given @obj
* @vmpage: pointer to kernel struct page
* @obj: cl_object (client side object) to which cl_page is to be returned
*
* Returns pointer to associated cl_page on success
*/
struct cl_page *cl_vmpage_page(struct page *vmpage, struct cl_object *obj)
{
struct cl_page *page;
ENTRY;
LASSERT(PageLocked(vmpage));
/*
* NOTE: absence of races and liveness of data are guaranteed by page
* lock on a "vmpage". That works because object destruction has
* bottom-to-top pass.
*/
page = (struct cl_page *)vmpage->private;
if (page != NULL) {
cl_page_get_trust(page);
LASSERT(page->cp_type == CPT_CACHEABLE);
}
RETURN(page);
}
EXPORT_SYMBOL(cl_vmpage_page);
static void cl_page_owner_clear(struct cl_page *page)
{
ENTRY;
if (page->cp_owner != NULL) {
LASSERT(page->cp_owner->ci_owned_nr > 0);
page->cp_owner->ci_owned_nr--;
page->cp_owner = NULL;
}
EXIT;
}
static void cl_page_owner_set(struct cl_page *page)
{
ENTRY;
LASSERT(page->cp_owner != NULL);
page->cp_owner->ci_owned_nr++;
EXIT;
}
void __cl_page_disown(const struct lu_env *env, struct cl_page *cp)
{
struct page *vmpage;
enum cl_page_state state;
ENTRY;
LASSERT(cp->cp_type != CPT_TRANSIENT);
cl_page_owner_clear(cp);
state = cp->cp_state;
PINVRNT(env, cp, state == CPS_OWNED || state == CPS_FREEING);
PINVRNT(env, cp, cl_page_invariant(cp) || state == CPS_FREEING);
if (state == CPS_OWNED)
cl_page_state_set(env, cp, CPS_CACHED);
vmpage = cp->cp_vmpage;
LASSERT(vmpage != NULL);
LASSERT(PageLocked(vmpage));
unlock_page(vmpage);
EXIT;
}
/* returns true, iff page is owned by the given io. */
int cl_page_is_owned(const struct cl_page *pg, const struct cl_io *io)
{
struct cl_io *top = cl_io_top((struct cl_io *)io);
LINVRNT(cl_object_same(pg->cp_obj, top->ci_obj));
ENTRY;
LASSERT(pg->cp_type != CPT_TRANSIENT);
RETURN(pg->cp_state == CPS_OWNED && pg->cp_owner == top);
}
EXPORT_SYMBOL(cl_page_is_owned);
/*
* Try to own a page by IO.
*
* Waits until page is in cl_page_state::CPS_CACHED state, and then switch it
* into cl_page_state::CPS_OWNED state.
*
* pre !cl_page_is_owned(cl_page, io)
* post result == 0 iff cl_page_is_owned(cl_page, io)
*
* retval 0 success
*
* retval -ve failure, e.g., cl_page was destroyed (and landed in
* cl_page_state::CPS_FREEING instead of cl_page_state::CPS_CACHED).
* or, page was owned by another thread, or in IO.
*
* see cl_page_disown()
* see cl_page_own_try()
* see cl_page_own
*/
static int __cl_page_own(const struct lu_env *env, struct cl_io *io,
struct cl_page *cl_page, int nonblock)
{
struct page *vmpage = cl_page->cp_vmpage;
int result;
ENTRY;
LASSERT(cl_page->cp_type != CPT_TRANSIENT);
PINVRNT(env, cl_page, !cl_page_is_owned(cl_page, io));
if (cl_page->cp_type != CPT_TRANSIENT &&
cl_page->cp_state == CPS_FREEING) {
result = -ENOENT;
goto out;
}
LASSERT(vmpage != NULL);
if (nonblock) {
if (!trylock_page(vmpage)) {
result = -EAGAIN;
goto out;
}
if (unlikely(PageWriteback(vmpage))) {
unlock_page(vmpage);
result = -EAGAIN;
goto out;
}
} else {
lock_page(vmpage);
wait_on_page_writeback(vmpage);
}
PASSERT(env, cl_page, cl_page->cp_owner == NULL);
cl_page->cp_owner = cl_io_top(io);
cl_page_owner_set(cl_page);
if (cl_page->cp_state == CPS_FREEING) {
__cl_page_disown(env, cl_page);
result = -ENOENT;
goto out;
}
cl_page_state_set(env, cl_page, CPS_OWNED);
result = 0;
out:
CDEBUG(D_INFO, "res %d\n", result);
PINVRNT(env, cl_page, ergo(result == 0,
cl_page_invariant(cl_page)));
RETURN(result);
}
/**
* cl_page_own() - Own a page, might be blocked. (see __cl_page_own())
* @env: current lustre environment
* @io: pointer to IO operation which wants to own @pg
* @pg: pointer to cl_page(page) which @io wants to own
*
* Return:
* * %0 on success
* * %negative on failure
*/
int cl_page_own(const struct lu_env *env, struct cl_io *io, struct cl_page *pg)
{
return __cl_page_own(env, io, pg, 0);
}
EXPORT_SYMBOL(cl_page_own);
/**
* cl_page_own_try() - Nonblock version of cl_page_own(). (see __cl_page_own())
* @env: current lustre environment
* @io: pointer to IO operation which wants to own @pg
* @pg: pointer to cl_page(page) which @io wants to own
*
* Return:
* * %0 on success
* * %negative on failure
*/
int cl_page_own_try(const struct lu_env *env, struct cl_io *io,
struct cl_page *pg)
{
return __cl_page_own(env, io, pg, 1);
}
EXPORT_SYMBOL(cl_page_own_try);
/**
* cl_page_assume() - Assume page ownership.
* @env: current lustre environment
* @io: pointer to IO operation which wants to assume @cp
* @cp: pointer to cl_page(page) which @io wants to assume
*
* Called when page is already locked by the hosting VM.
*
* pre !cl_page_is_owned(cp, io)
* post cl_page_is_owned(cp, io)
*/
void cl_page_assume(const struct lu_env *env,
struct cl_io *io, struct cl_page *cp)
{
struct page *vmpage;
ENTRY;
PINVRNT(env, cp, cl_object_same(cp->cp_obj, cl_io_top(io)->ci_obj));
LASSERT(cp->cp_type != CPT_TRANSIENT);
PASSERT(env, cp, cp->cp_owner == NULL);
vmpage = cp->cp_vmpage;
LASSERT(vmpage != NULL);
LASSERT(PageLocked(vmpage));
wait_on_page_writeback(vmpage);
cp->cp_owner = cl_io_top(io);
cl_page_owner_set(cp);
cl_page_state_set(env, cp, CPS_OWNED);
EXIT;
}
EXPORT_SYMBOL(cl_page_assume);
/**
* cl_page_unassume() - Releases page ownership without unlocking the page.
* @env: current lustre environment
* @io: pointer to IO operation which wants to unassume @cp
* @cp: pointer to cl_page(page) which @io wants to unassume
*
* Moves cl_page into cl_page_state::CPS_CACHED without releasing a lock
* on the underlying VM page (as VM is supposed to do this itself).
*
* pre cl_page_is_owned(cp, io)
* post !cl_page_is_owned(cp, io)
*/
void cl_page_unassume(const struct lu_env *env,
struct cl_io *io, struct cl_page *cp)
{
struct page *vmpage;
ENTRY;
LASSERT(cp->cp_type != CPT_TRANSIENT);
PINVRNT(env, cp, cl_page_is_owned(cp, io));
PINVRNT(env, cp, cl_page_invariant(cp));
cl_page_owner_clear(cp);
cl_page_state_set(env, cp, CPS_CACHED);
vmpage = cp->cp_vmpage;
LASSERT(vmpage != NULL);
LASSERT(PageLocked(vmpage));
EXIT;
}
EXPORT_SYMBOL(cl_page_unassume);
/**
* cl_page_disown() - Releases page ownership.
* @env: current lustre environment
* @io: pointer to IO operation which wants to release @pg
* @pg: pointer to cl_page(page) which @io wants to release
*
* Moves page into cl_page_state::CPS_CACHED.
*
* pre cl_page_is_owned(pg, io)
* post !cl_page_is_owned(pg, io)
*
* see cl_page_own()
*/
void cl_page_disown(const struct lu_env *env,
struct cl_io *io, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_is_owned(pg, cl_io_top(io)) ||
pg->cp_state == CPS_FREEING);
__cl_page_disown(env, pg);
}
EXPORT_SYMBOL(cl_page_disown);
/**
* cl_page_discard() - Called when cl_page is to be removed from the object
* @env: current lustre environment
* @io: pointer to IO operation which wants to discard @pg
* @cp: pointer to cl_page(page) which @io wants to discard
*
* Called when cl_page is to be removed from the object, e.g.,
* as a result of truncate.
*
* Calls cl_page_operations::cpo_discard() top-to-bottom.
*
* pre cl_page_is_owned(cl_page, io)
*
* see cl_page_operations::cpo_discard()
*/
void cl_page_discard(const struct lu_env *env,
struct cl_io *io, struct cl_page *cp)
{
struct page *vmpage;
const struct cl_page_slice *slice;
int i;
LASSERT(cp->cp_type != CPT_TRANSIENT);
cl_page_slice_for_each(cp, slice, i) {
if (slice->cpl_ops->cpo_discard != NULL)
(*slice->cpl_ops->cpo_discard)(env, slice, io);
}
PINVRNT(env, cp, cl_page_is_owned(cp, io));
PINVRNT(env, cp, cl_page_invariant(cp));
/* remove from radix tree if possible, lest generic_error_remove_page()
* failed to reach folio_invalidate()
*/
cl_page_delete(env, cp);
vmpage = cp->cp_vmpage;
LASSERT(vmpage != NULL);
LASSERT(PageLocked(vmpage));
generic_error_remove_folio(vmpage->mapping, page_folio(vmpage));
}
EXPORT_SYMBOL(cl_page_discard);
/*
* Version of cl_page_delete() that can be called for not fully constructed
* cl_pages, e.g. in an error handling cl_page_find()->__cl_page_delete()
* path. Doesn't check cl_page invariant.
*/
static void __cl_page_delete(const struct lu_env *env, struct cl_page *cp)
{
const struct cl_page_slice *slice;
int i;
ENTRY;
if (cp->cp_type == CPT_TRANSIENT)
EXIT;
/*
* Severe all ways to obtain new pointers to @pg.
* Transient pages already can't be found because they're not in cache.
*/
PASSERT(env, cp, cp->cp_state != CPS_FREEING);
cl_page_owner_clear(cp);
__cl_page_state_set(env, cp, CPS_FREEING);
cl_page_slice_for_each_reverse(cp, slice, i) {
if (slice->cpl_ops->cpo_delete != NULL)
(*slice->cpl_ops->cpo_delete)(env, slice);
}
EXIT;
}
/*
* Called when a decision is made to throw page out of memory.
*
* Notifies all layers about page destruction by calling
* cl_page_operations::cpo_delete() method top-to-bottom.
*
* Moves page into cl_page_state::CPS_FREEING state (this is the only place
* where transition to this state happens).
*
* Eliminates all venues through which new references to the page can be
* obtained:
*
* - removes page from the radix trees,
*
* - breaks linkage from VM page to cl_page.
*
* Once page reaches cl_page_state::CPS_FREEING, all remaining references will
* drain after some time, at which point page will be recycled.
*
* \pre VM page is locked
* \post pg->cp_state == CPS_FREEING
*
* \see cl_page_operations::cpo_delete()
*/
void cl_page_delete(const struct lu_env *env, struct cl_page *pg)
{
PINVRNT(env, pg, cl_page_invariant(pg));
ENTRY;
__cl_page_delete(env, pg);
EXIT;
}
EXPORT_SYMBOL(cl_page_delete);
void cl_page_touch(const struct lu_env *env,
const struct cl_page *cl_page, size_t to)
{
const struct cl_page_slice *slice;
int i;
ENTRY;
cl_page_slice_for_each(cl_page, slice, i) {
if (slice->cpl_ops->cpo_page_touch != NULL)
(*slice->cpl_ops->cpo_page_touch)(env, slice, to);
}
EXIT;
}
EXPORT_SYMBOL(cl_page_touch);
static enum cl_page_state cl_req_type_state(enum cl_req_type crt)
{
ENTRY;
RETURN(crt == CRT_WRITE ? CPS_PAGEOUT : CPS_PAGEIN);
}
static void cl_page_io_start(const struct lu_env *env,
struct cl_page *pg, enum cl_req_type crt)
{
/* Page is queued for IO, change its state. */
ENTRY;
cl_page_owner_clear(pg);
cl_page_state_set(env, pg, cl_req_type_state(crt));
EXIT;
}
/**
* cl_page_prep() - Prepares page for immediate transfer
* @env: current lustre environment
* @io: pointer to IO operation which wants to prep @cp
* @cp: pointer to cl_page(page) which @io wants to prep
* @crt: IO type (READ/WRITE)
*
* Return:
* * %0 on success (Prepares page for immediate transfer)
* * %-EALREADY if page should be omitted from transfer (alreay up-to-date)
*/
int cl_page_prep(const struct lu_env *env, struct cl_io *io,
struct cl_page *cp, enum cl_req_type crt)
{
struct page *vmpage = cp->cp_vmpage;
int rc;
LASSERT(cp->cp_type != CPT_TRANSIENT);
PASSERT(env, cp, crt < CRT_NR);
PINVRNT(env, cp, cl_page_is_owned(cp, io));
PINVRNT(env, cp, cl_page_invariant(cp));
if (crt == CRT_READ) {
if (PageUptodate(vmpage))
GOTO(out, rc = -EALREADY);
} else {
LASSERT(PageLocked(vmpage));
LASSERT(!PageDirty(vmpage));
/* ll_writepage path is not a sync write, so need to
* set page writeback flag
*/
if (cp->cp_sync_io == NULL)
set_page_writeback(vmpage);
}
cl_page_io_start(env, cp, crt);
rc = 0;
out:
CL_PAGE_HEADER(D_TRACE, env, cp, "%d %d\n", crt, rc);
return rc;
}
EXPORT_SYMBOL(cl_page_prep);
/* this is the equivalent of cl_page_complete for a dio pages struct, but is
* much simpler - in fact, it only needs to note the completion in the sync io
*/
void cl_dio_pages_complete(const struct lu_env *env, struct cl_dio_pages *cdp,
int count, int ioret)
{
struct cl_sub_dio *sdio = container_of(cdp, struct cl_sub_dio,
csd_dio_pages);
ENTRY;
__cl_sync_io_note(env, &sdio->csd_sync, count, ioret);
EXIT;
}
EXPORT_SYMBOL(cl_dio_pages_complete);
/**
* cl_page_complete() - Notify layers about transfer complete.
* @env: current lustre environment
* @cl_page: pointer to cl_page(page) of just completed IO
* @crt: IO type (READ/WRITE)
* @ioret: Returned IO status. %0 on success. %negative on failure
*
* Invoked by transfer sub-system (which is a part of osc) to notify layers
* that a transfer, of which this page is a part of has completed.
*
* Completion call-backs are executed in the bottom-up order, so that
* uppermost layer (llite), responsible for the VFS/VM interaction runs last
* and can release locks safely.
*
* pre cl_page->cp_state == CPS_PAGEIN || cl_page->cp_state == CPS_PAGEOUT
* post cl_page->cl_page_state == CPS_CACHED
*
* see cl_page_operations::cpo_complete()
*/
void cl_page_complete(const struct lu_env *env, struct cl_page *cl_page,
enum cl_req_type crt, int ioret)
{
const struct cl_page_slice *slice;
struct cl_sync_io *anchor = cl_page->cp_sync_io;
int i;
ENTRY;
CL_PAGE_HEADER(D_TRACE, env, cl_page, "%d %d\n", crt, ioret);
PASSERT(env, cl_page, crt < CRT_NR);
if (cl_page->cp_type != CPT_TRANSIENT) {
PASSERT(env, cl_page,
cl_page->cp_state == cl_req_type_state(crt));
cl_page_state_set(env, cl_page, CPS_CACHED);
cl_page_slice_for_each_reverse(cl_page, slice, i) {
if (slice->cpl_ops->io[crt].cpo_complete != NULL)
(*slice->cpl_ops->io[crt].cpo_complete)(env,
slice,
ioret);
}
}
if (anchor != NULL) {
LASSERT(cl_page->cp_sync_io == anchor);
cl_page->cp_sync_io = NULL;
cl_sync_io_note(env, anchor, ioret);
}
EXIT;
}
EXPORT_SYMBOL(cl_page_complete);
/**
* cl_page_make_ready() - Make page ready for IO
* @env: current lustre environment
* @cp: pointer to cl_page(page) which is marked to be ready
* @crt: IO type (READ/WRITE)
*
* Notify layers that transfer formation engine decided to yank this page from
* the cache and to make it a part of a transfer.
*
* \pre cl_page->cp_state == CPS_CACHED
* \post cl_page->cp_state == CPS_PAGEIN || cl_page->cp_state == CPS_PAGEOUT
*/
int cl_page_make_ready(const struct lu_env *env, struct cl_page *cp,
enum cl_req_type crt)
{
struct page *vmpage = cp->cp_vmpage;
bool unlock = false;
int rc = 0;
ENTRY;
PASSERT(env, cp, crt == CRT_WRITE);
LASSERT(cp->cp_type != CPT_TRANSIENT);
lock_page(vmpage);
PASSERT(env, cp, PageUptodate(vmpage));
unlock = true;
if (clear_page_dirty_for_io(vmpage)) {
LASSERT(cp->cp_state == CPS_CACHED);
/* This actually clears the dirty bit in the radix tree */
set_page_writeback(vmpage);
CL_PAGE_HEADER(D_PAGE, env, cp, "readied\n");
rc = 0;
} else if (cp->cp_state == CPS_PAGEOUT) {
/* is it possible for osc_flush_async_page()
* to already make it ready?
*/
rc = -EALREADY;
} else {
CL_PAGE_DEBUG(D_ERROR, env, cp,
"unexpecting page state %d\n",
cp->cp_state);
LBUG();
}
if (rc == 0) {
PASSERT(env, cp, cp->cp_state == CPS_CACHED);
cl_page_io_start(env, cp, crt);
}
if (unlock)
unlock_page(vmpage);
CL_PAGE_HEADER(D_TRACE, env, cp, "%d %d\n", crt, rc);
return rc;
}
EXPORT_SYMBOL(cl_page_make_ready);
/**
* cl_page_clip() - Mark only part(clip) of page for transmission
* @env: current lustre environment
* @cl_page: pointer to cl_page(page) which @io wants clip
* @from: Start of clip
* @to: length to clip
*
* Tells transfer engine that only part of a page is to be transmitted.
*
* see cl_page_operations::cpo_clip()
*/
void cl_page_clip(const struct lu_env *env, struct cl_page *cl_page,
int from, int to)
{
const struct cl_page_slice *slice;
int i;
PINVRNT(env, cl_page, cl_page_invariant(cl_page));
CL_PAGE_HEADER(D_TRACE, env, cl_page, "%d %d\n", from, to);
cl_page_slice_for_each(cl_page, slice, i) {
if (slice->cpl_ops->cpo_clip != NULL)
(*slice->cpl_ops->cpo_clip)(env, slice, from, to);
}
}
EXPORT_SYMBOL(cl_page_clip);
/* Prints human readable representation of \a pg to the \a f. */
void cl_page_header_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_page *pg)
{
(*printer)(env, cookie,
"page@%p[%d %p %d %d %p %u %d %lu]\n",
pg, refcount_read(&pg->cp_ref), pg->cp_obj,
pg->cp_state, pg->cp_type, pg->cp_owner,
pg->cp_lov_index, pg->cp_defer_uptodate,
pg->cp_page_index);
}
EXPORT_SYMBOL(cl_page_header_print);
/* Prints human readable representation of \a cl_page to the \a f. */
void cl_page_print(const struct lu_env *env, void *cookie,
lu_printer_t printer, const struct cl_page *cp)
{
struct page *vmpage = cp->cp_vmpage;
const struct cl_page_slice *slice;
int result = 0;
int i;
cl_page_header_print(env, cookie, printer, cp);
(*printer)(env, cookie, "vmpage @%p", vmpage);
if (vmpage != NULL) {
(*printer)(env, cookie, " %lx %d:%d %lx %lu %slru",
PAGE_FLAGS(vmpage), page_count(vmpage),
folio_mapcount_page(vmpage), vmpage->private,
folio_index_page(vmpage),
list_empty(&vmpage->lru) ? "not-" : "");
}
(*printer)(env, cookie, "\n");
cl_page_slice_for_each(cp, slice, i) {
if (slice->cpl_ops->cpo_print != NULL)
result = (*slice->cpl_ops->cpo_print)(env, slice,
cookie, printer);
if (result != 0)
break;
}
(*printer)(env, cookie, "end page@%p\n", cp);
}
EXPORT_SYMBOL(cl_page_print);
/**
* cl_page_slice_add() - Adds page slice to the compound page.
* @cl_page: pointer to cl_page(page) which @slice is being added
* @slice: slice(each layer specific data) which is getting added to @cl_page
* @obj: layer which is adding the slice
* @ops: pointer to cl_page_operations
*
* This is called by cl_object_operations::coo_page_init() methods to add a
* per-layer state to the page. New state is added at the end of
* cl_page::cp_layers list, that is, it is at the bottom of the stack.
*
* see cl_lock_slice_add(), cl_req_slice_add(), cl_io_slice_add()
*/
void cl_page_slice_add(struct cl_page *cl_page, struct cl_page_slice *slice,
struct cl_object *obj,
const struct cl_page_operations *ops)
{
unsigned int offset = (char *)slice -
((char *)cl_page + sizeof(*cl_page));
ENTRY;
LASSERT(cl_page->cp_layer_count < CP_MAX_LAYER);
LASSERT(offset < (1 << sizeof(cl_page->cp_layer_offset[0]) * 8));
cl_page->cp_layer_offset[cl_page->cp_layer_count++] = offset;
slice->cpl_ops = ops;
slice->cpl_page = cl_page;
EXIT;
}
EXPORT_SYMBOL(cl_page_slice_add);
/* Allocate and initialize cl_cache, called by ll_init_sbi(). */
struct cl_client_cache *cl_cache_init(unsigned long lru_page_max)
{
struct cl_client_cache *cache = NULL;
ENTRY;
OBD_ALLOC(cache, sizeof(*cache));
if (cache == NULL)
RETURN(NULL);
/* Initialize cache data */
refcount_set(&cache->ccc_users, 1);
cache->ccc_lru_max = lru_page_max;
atomic_long_set(&cache->ccc_lru_left, lru_page_max);
atomic_long_set(&cache->ccc_unevict_lru_used, 0);
spin_lock_init(&cache->ccc_lru_lock);
INIT_LIST_HEAD(&cache->ccc_lru);
cache->ccc_unstable_check = 1;
atomic_long_set(&cache->ccc_unstable_nr, 0);
mutex_init(&cache->ccc_max_cache_mb_lock);
RETURN(cache);
}
EXPORT_SYMBOL(cl_cache_init);
/* Increase cl_cache refcount */
void cl_cache_incref(struct cl_client_cache *cache)
{
refcount_inc(&cache->ccc_users);
}
EXPORT_SYMBOL(cl_cache_incref);
/*
* Decrease cl_cache refcount and free the cache if refcount=0.
* Since llite, lov and osc all hold cl_cache refcount,
* the free will not cause race. (LU-6173)
*/
void cl_cache_decref(struct cl_client_cache *cache)
{
if (refcount_dec_and_test(&cache->ccc_users))
OBD_FREE(cache, sizeof(*cache));
}
EXPORT_SYMBOL(cl_cache_decref);
