Re: Helding the Kernel lock while doing IO??? (take 2)

["Juan J. Quintela" <quintela@fi.udc.es>]

>>>>> "juan" == Juan J Quintela <quintela@fi.udc.es> writes:

juan> Hi
juan> In the function m/memory.c()::do_swap_page():

juan> lock_kernel();
juan> swapin_readahead(entry);
juan> page = read_swap_cache(entry);
juan> unlock_kernel();

juan> read_swap_cache is called synchronously, then we can have to wait
juan> until we read the page to liberate the lock kernel.  It is intended?
juan> I am losing some detail?

juan> I have  changed that in the two places that happened.

juan> Thanks in advance for any response.

Sorry for the inconveniences.

First one lacks a wait_on_page:

diff -u -urN --exclude=CVS --exclude=*~ --exclude=.#* --exclude=TAGS pre7-6/ipc/shm.c testing/ipc/shm.c
--- pre7-6/ipc/shm.c	Fri May  5 23:58:56 2000
+++ testing/ipc/shm.c	Sat May  6 03:16:34 2000
@@ -1379,10 +1379,11 @@
 			if (!page) {
 				lock_kernel();
 				swapin_readahead(entry);
-				page = read_swap_cache(entry);
+				page = read_swap_cache_async(entry, 0);
 				unlock_kernel();
 				if (!page)
 					goto oom;
+                                wait_on_page(page);
 			}
 			delete_from_swap_cache(page);
 			page = replace_with_highmem(page);
diff -u -urN --exclude=CVS --exclude=*~ --exclude=.#* --exclude=TAGS pre7-6/mm/memory.c testing/mm/memory.c
--- pre7-6/mm/memory.c	Fri May  5 23:58:56 2000
+++ testing/mm/memory.c	Sat May  6 03:25:47 2000
@@ -1038,11 +1038,11 @@
 	if (!page) {
 		lock_kernel();
 		swapin_readahead(entry);
-		page = read_swap_cache(entry);
+		page = read_swap_cache_async(entry, 0);
 		unlock_kernel();
 		if (!page)
 			return -1;
-
+                wait_on_page(page);
 		flush_page_to_ram(page);
 		flush_icache_page(vma, page);
 	}



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