linux-5.15/isolate_lru_pages()
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開始行:
*参照元 [#w4116c8e]
#backlinks
*説明 [#e45b90b4]
-パス: [[linux-5.15/mm/vmscan.c]]
-FIXME: これは何？
--説明
**引数 [#ncde76d3]
-unsigned long nr_to_scan
--
-struct lruvec *lruvec
--
--[[linux-5.15/lruvec]]
-struct list_head *dst
--
--[[linux-5.15/list_head]]
-unsigned long *nr_scanned
--
-struct scan_control *sc
--
--[[linux-5.15/scan_control]]
-enum lru_list lru
--
--[[linux-5.15/lru_list]]
**返り値 [#g28b4382]
-unsigned long
--
**参考 [#cf2e02fa]
*実装 [#t08d6a17]
/*
* Isolating page from the lruvec to fill in @dst list b...
*
* lruvec->lru_lock is heavily contended. Some of the f...
* shrink the lists perform better by taking out a batch...
* and working on them outside the LRU lock.
*
* For pagecache intensive workloads, this function is t...
* spot in the kernel (apart from copy_*_user functions).
*
* Lru_lock must be held before calling this function.
*
* @nr_to_scan: The number of eligible pages to look thr...
* @lruvec: The LRU vector to pull pages from.
* @dst: The temp list to put pages on to.
* @nr_scanned: The number of pages that were scanned.
* @sc: The scan_control struct for this reclaim session
* @lru: LRU list id for isolating
*
* returns how many pages were moved onto *@dst.
*/
static unsigned long isolate_lru_pages(unsigned long nr_...
struct lruvec *lruvec, struct list_head *dst,
unsigned long *nr_scanned, struct scan_control *sc,
enum lru_list lru)
{
struct list_head *src = &lruvec->lists[lru];
unsigned long nr_taken = 0;
unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
unsigned long skipped = 0;
unsigned long scan, total_scan, nr_pages;
LIST_HEAD(pages_skipped);
isolate_mode_t mode = (sc->may_unmap ? 0 : ISOLATE_UNMA...
-
--[[linux-5.15/list_head]]
--[[linux-5.15/LIST_HEAD()]]
total_scan = 0;
scan = 0;
while (scan < nr_to_scan && !list_empty(src)) {
struct page *page;
page = lru_to_page(src);
prefetchw_prev_lru_page(page, src, flags);
nr_pages = compound_nr(page);
total_scan += nr_pages;
if (page_zonenum(page) > sc->reclaim_idx) {
list_move(&page->lru, &pages_skipped);
nr_skipped[page_zonenum(page)] += nr_pages;
continue;
}
-
--[[linux-5.15/list_empty()]]
--[[linux-5.15/lru_to_page()]]
--[[linux-5.15/prefetchw_prev_lru_page()]]
--[[linux-5.15/page_zonenum()]]
--[[linux-5.15/list_move()]]
/*
* Do not count skipped pages because that makes the f...
* return with no isolated pages if the LRU mostly con...
* ineligible pages. This causes the VM to not reclai...
* pages, triggering a premature OOM.
*
* Account all tail pages of THP. This would not cause
* premature OOM since __isolate_lru_page() returns -E...
* only when the page is being freed somewhere else.
*/
scan += nr_pages;
if (!__isolate_lru_page_prepare(page, mode)) {
/* It is being freed elsewhere */
list_move(&page->lru, src);
continue;
}
-
--[[linux-5.15/isolate_lru_page_prepare()]]
--[[linux-5.15/list_move()]]
/*
* Be careful not to clear PageLRU until after we're
* sure the page is not being freed elsewhere -- the
* page release code relies on it.
*/
if (unlikely(!get_page_unless_zero(page))) {
list_move(&page->lru, src);
continue;
}
-
--[[linux-5.15/unlikely()]]
--[[linux-5.15/get_page_unless_zero()]]
--[[linux-5.15/list_move()]]
if (!TestClearPageLRU(page)) {
/* Another thread is already isolating this page */
put_page(page);
list_move(&page->lru, src);
continue;
}
-
--[[linux-5.15/TestClearPageLRU()]]
--[[linux-5.15/put_page()]]
--[[linux-5.15/list_move()]]
nr_taken += nr_pages;
nr_zone_taken[page_zonenum(page)] += nr_pages;
list_move(&page->lru, dst);
}
-
--[[linux-5.15/list_move()]]
/*
* Splice any skipped pages to the start of the LRU lis...
* this disrupts the LRU order when reclaiming for lowe...
* we cannot splice to the tail. If we did then the SWA...
* scanning would soon rescan the same pages to skip an...
* system at risk of premature OOM.
*/
if (!list_empty(&pages_skipped)) {
int zid;
list_splice(&pages_skipped, src);
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
if (!nr_skipped[zid])
continue;
__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zi...
skipped += nr_skipped[zid];
}
}
*nr_scanned = total_scan;
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order,...
total_scan, skipped, nr_taken, mode, lru);
update_lru_sizes(lruvec, lru, nr_zone_taken);
return nr_taken;
}
-
--[[linux-5.15/list_empty()]]
--[[linux-5.15/list_splice()]]
--[[linux-5.15/__count_zid_vm_events()]]
--[[linux-5.15/trace_mm_vmscan_lru_isolate()]]
--[[linux-5.15/update_lru_sizes()]]
*コメント [#r2c53b57]
終了行:
*参照元 [#w4116c8e]
#backlinks
*説明 [#e45b90b4]
-パス: [[linux-5.15/mm/vmscan.c]]
-FIXME: これは何？
--説明
**引数 [#ncde76d3]
-unsigned long nr_to_scan
--
-struct lruvec *lruvec
--
--[[linux-5.15/lruvec]]
-struct list_head *dst
--
--[[linux-5.15/list_head]]
-unsigned long *nr_scanned
--
-struct scan_control *sc
--
--[[linux-5.15/scan_control]]
-enum lru_list lru
--
--[[linux-5.15/lru_list]]
**返り値 [#g28b4382]
-unsigned long
--
**参考 [#cf2e02fa]
*実装 [#t08d6a17]
/*
* Isolating page from the lruvec to fill in @dst list b...
*
* lruvec->lru_lock is heavily contended. Some of the f...
* shrink the lists perform better by taking out a batch...
* and working on them outside the LRU lock.
*
* For pagecache intensive workloads, this function is t...
* spot in the kernel (apart from copy_*_user functions).
*
* Lru_lock must be held before calling this function.
*
* @nr_to_scan: The number of eligible pages to look thr...
* @lruvec: The LRU vector to pull pages from.
* @dst: The temp list to put pages on to.
* @nr_scanned: The number of pages that were scanned.
* @sc: The scan_control struct for this reclaim session
* @lru: LRU list id for isolating
*
* returns how many pages were moved onto *@dst.
*/
static unsigned long isolate_lru_pages(unsigned long nr_...
struct lruvec *lruvec, struct list_head *dst,
unsigned long *nr_scanned, struct scan_control *sc,
enum lru_list lru)
{
struct list_head *src = &lruvec->lists[lru];
unsigned long nr_taken = 0;
unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
unsigned long skipped = 0;
unsigned long scan, total_scan, nr_pages;
LIST_HEAD(pages_skipped);
isolate_mode_t mode = (sc->may_unmap ? 0 : ISOLATE_UNMA...
-
--[[linux-5.15/list_head]]
--[[linux-5.15/LIST_HEAD()]]
total_scan = 0;
scan = 0;
while (scan < nr_to_scan && !list_empty(src)) {
struct page *page;
page = lru_to_page(src);
prefetchw_prev_lru_page(page, src, flags);
nr_pages = compound_nr(page);
total_scan += nr_pages;
if (page_zonenum(page) > sc->reclaim_idx) {
list_move(&page->lru, &pages_skipped);
nr_skipped[page_zonenum(page)] += nr_pages;
continue;
}
-
--[[linux-5.15/list_empty()]]
--[[linux-5.15/lru_to_page()]]
--[[linux-5.15/prefetchw_prev_lru_page()]]
--[[linux-5.15/page_zonenum()]]
--[[linux-5.15/list_move()]]
/*
* Do not count skipped pages because that makes the f...
* return with no isolated pages if the LRU mostly con...
* ineligible pages. This causes the VM to not reclai...
* pages, triggering a premature OOM.
*
* Account all tail pages of THP. This would not cause
* premature OOM since __isolate_lru_page() returns -E...
* only when the page is being freed somewhere else.
*/
scan += nr_pages;
if (!__isolate_lru_page_prepare(page, mode)) {
/* It is being freed elsewhere */
list_move(&page->lru, src);
continue;
}
-
--[[linux-5.15/isolate_lru_page_prepare()]]
--[[linux-5.15/list_move()]]
/*
* Be careful not to clear PageLRU until after we're
* sure the page is not being freed elsewhere -- the
* page release code relies on it.
*/
if (unlikely(!get_page_unless_zero(page))) {
list_move(&page->lru, src);
continue;
}
-
--[[linux-5.15/unlikely()]]
--[[linux-5.15/get_page_unless_zero()]]
--[[linux-5.15/list_move()]]
if (!TestClearPageLRU(page)) {
/* Another thread is already isolating this page */
put_page(page);
list_move(&page->lru, src);
continue;
}
-
--[[linux-5.15/TestClearPageLRU()]]
--[[linux-5.15/put_page()]]
--[[linux-5.15/list_move()]]
nr_taken += nr_pages;
nr_zone_taken[page_zonenum(page)] += nr_pages;
list_move(&page->lru, dst);
}
-
--[[linux-5.15/list_move()]]
/*
* Splice any skipped pages to the start of the LRU lis...
* this disrupts the LRU order when reclaiming for lowe...
* we cannot splice to the tail. If we did then the SWA...
* scanning would soon rescan the same pages to skip an...
* system at risk of premature OOM.
*/
if (!list_empty(&pages_skipped)) {
int zid;
list_splice(&pages_skipped, src);
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
if (!nr_skipped[zid])
continue;
__count_zid_vm_events(PGSCAN_SKIP, zid, nr_skipped[zi...
skipped += nr_skipped[zid];
}
}
*nr_scanned = total_scan;
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order,...
total_scan, skipped, nr_taken, mode, lru);
update_lru_sizes(lruvec, lru, nr_zone_taken);
return nr_taken;
}
-
--[[linux-5.15/list_empty()]]
--[[linux-5.15/list_splice()]]
--[[linux-5.15/__count_zid_vm_events()]]
--[[linux-5.15/trace_mm_vmscan_lru_isolate()]]
--[[linux-5.15/update_lru_sizes()]]
*コメント [#r2c53b57]
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